kernel/bpf/btf.c

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This source file includes following definitions.
btf_type_is_modifier
btf_type_is_void
btf_type_is_fwd
btf_type_is_func
btf_type_is_func_proto
btf_type_nosize
btf_type_nosize_or_null
btf_type_is_struct
__btf_type_is_struct
btf_type_is_array
btf_type_is_ptr
btf_type_is_int
btf_type_is_var
btf_type_is_datasec
btf_type_is_resolve_source_only
btf_type_needs_resolve
btf_type_has_size
btf_int_encoding_str
btf_type_vlen
btf_type_kflag
btf_member_bit_offset
btf_member_bitfield_size
btf_type_int
btf_type_array
btf_type_member
btf_type_enum
btf_type_var
btf_type_var_secinfo
btf_type_ops
btf_name_offset_valid
__btf_name_char_ok
__btf_name_valid
btf_name_valid_identifier
btf_name_valid_section
__btf_name_by_offset
btf_name_by_offset
btf_type_by_id
btf_type_int_is_regular
btf_member_is_reg_int
__printf
__printf
__printf
__printf
__printf
btf_verifier_log_hdr
btf_add_type
btf_alloc_id
btf_free_id
btf_free
btf_free_rcu
btf_put
env_resolve_init
btf_verifier_env_free
env_type_is_resolve_sink
env_type_is_resolved
env_stack_push
env_stack_set_next_member
env_stack_pop_resolved
env_stack_peak
btf_type_id_resolve
btf_type_id_size
btf_df_check_member
btf_df_check_kflag_member
btf_generic_check_kflag_member
btf_df_resolve
btf_df_seq_show
btf_int_check_member
btf_int_check_kflag_member
btf_int_check_meta
btf_int_log
btf_int128_print
btf_int128_shift
btf_bitfield_seq_show
btf_int_bits_seq_show
btf_int_seq_show
btf_modifier_check_member
btf_modifier_check_kflag_member
btf_ptr_check_member
btf_ref_type_check_meta
btf_modifier_resolve
btf_var_resolve
btf_ptr_resolve
btf_modifier_seq_show
btf_var_seq_show
btf_ptr_seq_show
btf_ref_type_log
btf_fwd_check_meta
btf_fwd_type_log
btf_array_check_member
btf_array_check_meta
btf_array_resolve
btf_array_log
btf_array_seq_show
btf_struct_check_member
btf_struct_check_meta
btf_struct_resolve
btf_struct_log
btf_find_spin_lock
btf_struct_seq_show
btf_enum_check_member
btf_enum_check_kflag_member
btf_enum_check_meta
btf_enum_log
btf_enum_seq_show
btf_func_proto_check_meta
btf_func_proto_log
btf_func_check_meta
btf_var_check_meta
btf_var_log
btf_datasec_check_meta
btf_datasec_resolve
btf_datasec_log
btf_datasec_seq_show
btf_func_proto_check
btf_func_check
btf_check_meta
btf_check_all_metas
btf_resolve_valid
btf_resolve
btf_check_all_types
btf_parse_type_sec
btf_parse_str_sec
btf_sec_info_cmp
btf_check_sec_info
btf_parse_hdr
btf_parse
btf_type_seq_show
bpf_btf_show_fdinfo
btf_release
__btf_new_fd
btf_new_fd
btf_get_by_fd
btf_get_info_by_fd
btf_get_fd_by_id
btf_id
   1 /* SPDX-License-Identifier: GPL-2.0 */
   2 /* Copyright (c) 2018 Facebook */
   3 
   4 #include <uapi/linux/btf.h>
   5 #include <uapi/linux/types.h>
   6 #include <linux/seq_file.h>
   7 #include <linux/compiler.h>
   8 #include <linux/ctype.h>
   9 #include <linux/errno.h>
  10 #include <linux/slab.h>
  11 #include <linux/anon_inodes.h>
  12 #include <linux/file.h>
  13 #include <linux/uaccess.h>
  14 #include <linux/kernel.h>
  15 #include <linux/idr.h>
  16 #include <linux/sort.h>
  17 #include <linux/bpf_verifier.h>
  18 #include <linux/btf.h>
  19 
  20 /* BTF (BPF Type Format) is the meta data format which describes
  21  * the data types of BPF program/map.  Hence, it basically focus
  22  * on the C programming language which the modern BPF is primary
  23  * using.
  24  *
  25  * ELF Section:
  26  * ~~~~~~~~~~~
  27  * The BTF data is stored under the ".BTF" ELF section
  28  *
  29  * struct btf_type:
  30  * ~~~~~~~~~~~~~~~
  31  * Each 'struct btf_type' object describes a C data type.
  32  * Depending on the type it is describing, a 'struct btf_type'
  33  * object may be followed by more data.  F.e.
  34  * To describe an array, 'struct btf_type' is followed by
  35  * 'struct btf_array'.
  36  *
  37  * 'struct btf_type' and any extra data following it are
  38  * 4 bytes aligned.
  39  *
  40  * Type section:
  41  * ~~~~~~~~~~~~~
  42  * The BTF type section contains a list of 'struct btf_type' objects.
  43  * Each one describes a C type.  Recall from the above section
  44  * that a 'struct btf_type' object could be immediately followed by extra
  45  * data in order to desribe some particular C types.
  46  *
  47  * type_id:
  48  * ~~~~~~~
  49  * Each btf_type object is identified by a type_id.  The type_id
  50  * is implicitly implied by the location of the btf_type object in
  51  * the BTF type section.  The first one has type_id 1.  The second
  52  * one has type_id 2...etc.  Hence, an earlier btf_type has
  53  * a smaller type_id.
  54  *
  55  * A btf_type object may refer to another btf_type object by using
  56  * type_id (i.e. the "type" in the "struct btf_type").
  57  *
  58  * NOTE that we cannot assume any reference-order.
  59  * A btf_type object can refer to an earlier btf_type object
  60  * but it can also refer to a later btf_type object.
  61  *
  62  * For example, to describe "const void *".  A btf_type
  63  * object describing "const" may refer to another btf_type
  64  * object describing "void *".  This type-reference is done
  65  * by specifying type_id:
  66  *
  67  * [1] CONST (anon) type_id=2
  68  * [2] PTR (anon) type_id=0
  69  *
  70  * The above is the btf_verifier debug log:
  71  *   - Each line started with "[?]" is a btf_type object
  72  *   - [?] is the type_id of the btf_type object.
  73  *   - CONST/PTR is the BTF_KIND_XXX
  74  *   - "(anon)" is the name of the type.  It just
  75  *     happens that CONST and PTR has no name.
  76  *   - type_id=XXX is the 'u32 type' in btf_type
  77  *
  78  * NOTE: "void" has type_id 0
  79  *
  80  * String section:
  81  * ~~~~~~~~~~~~~~
  82  * The BTF string section contains the names used by the type section.
  83  * Each string is referred by an "offset" from the beginning of the
  84  * string section.
  85  *
  86  * Each string is '\0' terminated.
  87  *
  88  * The first character in the string section must be '\0'
  89  * which is used to mean 'anonymous'. Some btf_type may not
  90  * have a name.
  91  */
  92 
  93 /* BTF verification:
  94  *
  95  * To verify BTF data, two passes are needed.
  96  *
  97  * Pass #1
  98  * ~~~~~~~
  99  * The first pass is to collect all btf_type objects to
 100  * an array: "btf->types".
 101  *
 102  * Depending on the C type that a btf_type is describing,
 103  * a btf_type may be followed by extra data.  We don't know
 104  * how many btf_type is there, and more importantly we don't
 105  * know where each btf_type is located in the type section.
 106  *
 107  * Without knowing the location of each type_id, most verifications
 108  * cannot be done.  e.g. an earlier btf_type may refer to a later
 109  * btf_type (recall the "const void *" above), so we cannot
 110  * check this type-reference in the first pass.
 111  *
 112  * In the first pass, it still does some verifications (e.g.
 113  * checking the name is a valid offset to the string section).
 114  *
 115  * Pass #2
 116  * ~~~~~~~
 117  * The main focus is to resolve a btf_type that is referring
 118  * to another type.
 119  *
 120  * We have to ensure the referring type:
 121  * 1) does exist in the BTF (i.e. in btf->types[])
 122  * 2) does not cause a loop:
 123  *      struct A {
 124  *              struct B b;
 125  *      };
 126  *
 127  *      struct B {
 128  *              struct A a;
 129  *      };
 130  *
 131  * btf_type_needs_resolve() decides if a btf_type needs
 132  * to be resolved.
 133  *
 134  * The needs_resolve type implements the "resolve()" ops which
 135  * essentially does a DFS and detects backedge.
 136  *
 137  * During resolve (or DFS), different C types have different
 138  * "RESOLVED" conditions.
 139  *
 140  * When resolving a BTF_KIND_STRUCT, we need to resolve all its
 141  * members because a member is always referring to another
 142  * type.  A struct's member can be treated as "RESOLVED" if
 143  * it is referring to a BTF_KIND_PTR.  Otherwise, the
 144  * following valid C struct would be rejected:
 145  *
 146  *      struct A {
 147  *              int m;
 148  *              struct A *a;
 149  *      };
 150  *
 151  * When resolving a BTF_KIND_PTR, it needs to keep resolving if
 152  * it is referring to another BTF_KIND_PTR.  Otherwise, we cannot
 153  * detect a pointer loop, e.g.:
 154  * BTF_KIND_CONST -> BTF_KIND_PTR -> BTF_KIND_CONST -> BTF_KIND_PTR +
 155  *                        ^                                         |
 156  *                        +-----------------------------------------+
 157  *
 158  */
 159 
 160 #define BITS_PER_U128 (sizeof(u64) * BITS_PER_BYTE * 2)
 161 #define BITS_PER_BYTE_MASK (BITS_PER_BYTE - 1)
 162 #define BITS_PER_BYTE_MASKED(bits) ((bits) & BITS_PER_BYTE_MASK)
 163 #define BITS_ROUNDDOWN_BYTES(bits) ((bits) >> 3)
 164 #define BITS_ROUNDUP_BYTES(bits) \
 165         (BITS_ROUNDDOWN_BYTES(bits) + !!BITS_PER_BYTE_MASKED(bits))
 166 
 167 #define BTF_INFO_MASK 0x8f00ffff
 168 #define BTF_INT_MASK 0x0fffffff
 169 #define BTF_TYPE_ID_VALID(type_id) ((type_id) <= BTF_MAX_TYPE)
 170 #define BTF_STR_OFFSET_VALID(name_off) ((name_off) <= BTF_MAX_NAME_OFFSET)
 171 
 172 /* 16MB for 64k structs and each has 16 members and
 173  * a few MB spaces for the string section.
 174  * The hard limit is S32_MAX.
 175  */
 176 #define BTF_MAX_SIZE (16 * 1024 * 1024)
 177 
 178 #define for_each_member(i, struct_type, member)                 \
 179         for (i = 0, member = btf_type_member(struct_type);      \
 180              i < btf_type_vlen(struct_type);                    \
 181              i++, member++)
 182 
 183 #define for_each_member_from(i, from, struct_type, member)              \
 184         for (i = from, member = btf_type_member(struct_type) + from;    \
 185              i < btf_type_vlen(struct_type);                            \
 186              i++, member++)
 187 
 188 #define for_each_vsi(i, struct_type, member)                    \
 189         for (i = 0, member = btf_type_var_secinfo(struct_type); \
 190              i < btf_type_vlen(struct_type);                    \
 191              i++, member++)
 192 
 193 #define for_each_vsi_from(i, from, struct_type, member)                         \
 194         for (i = from, member = btf_type_var_secinfo(struct_type) + from;       \
 195              i < btf_type_vlen(struct_type);                                    \
 196              i++, member++)
 197 
 198 DEFINE_IDR(btf_idr);
 199 DEFINE_SPINLOCK(btf_idr_lock);
 200 
 201 struct btf {
 202         void *data;
 203         struct btf_type **types;
 204         u32 *resolved_ids;
 205         u32 *resolved_sizes;
 206         const char *strings;
 207         void *nohdr_data;
 208         struct btf_header hdr;
 209         u32 nr_types;
 210         u32 types_size;
 211         u32 data_size;
 212         refcount_t refcnt;
 213         u32 id;
 214         struct rcu_head rcu;
 215 };
 216 
 217 enum verifier_phase {
 218         CHECK_META,
 219         CHECK_TYPE,
 220 };
 221 
 222 struct resolve_vertex {
 223         const struct btf_type *t;
 224         u32 type_id;
 225         u16 next_member;
 226 };
 227 
 228 enum visit_state {
 229         NOT_VISITED,
 230         VISITED,
 231         RESOLVED,
 232 };
 233 
 234 enum resolve_mode {
 235         RESOLVE_TBD,    /* To Be Determined */
 236         RESOLVE_PTR,    /* Resolving for Pointer */
 237         RESOLVE_STRUCT_OR_ARRAY,        /* Resolving for struct/union
 238                                          * or array
 239                                          */
 240 };
 241 
 242 #define MAX_RESOLVE_DEPTH 32
 243 
 244 struct btf_sec_info {
 245         u32 off;
 246         u32 len;
 247 };
 248 
 249 struct btf_verifier_env {
 250         struct btf *btf;
 251         u8 *visit_states;
 252         struct resolve_vertex stack[MAX_RESOLVE_DEPTH];
 253         struct bpf_verifier_log log;
 254         u32 log_type_id;
 255         u32 top_stack;
 256         enum verifier_phase phase;
 257         enum resolve_mode resolve_mode;
 258 };
 259 
 260 static const char * const btf_kind_str[NR_BTF_KINDS] = {
 261         [BTF_KIND_UNKN]         = "UNKNOWN",
 262         [BTF_KIND_INT]          = "INT",
 263         [BTF_KIND_PTR]          = "PTR",
 264         [BTF_KIND_ARRAY]        = "ARRAY",
 265         [BTF_KIND_STRUCT]       = "STRUCT",
 266         [BTF_KIND_UNION]        = "UNION",
 267         [BTF_KIND_ENUM]         = "ENUM",
 268         [BTF_KIND_FWD]          = "FWD",
 269         [BTF_KIND_TYPEDEF]      = "TYPEDEF",
 270         [BTF_KIND_VOLATILE]     = "VOLATILE",
 271         [BTF_KIND_CONST]        = "CONST",
 272         [BTF_KIND_RESTRICT]     = "RESTRICT",
 273         [BTF_KIND_FUNC]         = "FUNC",
 274         [BTF_KIND_FUNC_PROTO]   = "FUNC_PROTO",
 275         [BTF_KIND_VAR]          = "VAR",
 276         [BTF_KIND_DATASEC]      = "DATASEC",
 277 };
 278 
 279 struct btf_kind_operations {
 280         s32 (*check_meta)(struct btf_verifier_env *env,
 281                           const struct btf_type *t,
 282                           u32 meta_left);
 283         int (*resolve)(struct btf_verifier_env *env,
 284                        const struct resolve_vertex *v);
 285         int (*check_member)(struct btf_verifier_env *env,
 286                             const struct btf_type *struct_type,
 287                             const struct btf_member *member,
 288                             const struct btf_type *member_type);
 289         int (*check_kflag_member)(struct btf_verifier_env *env,
 290                                   const struct btf_type *struct_type,
 291                                   const struct btf_member *member,
 292                                   const struct btf_type *member_type);
 293         void (*log_details)(struct btf_verifier_env *env,
 294                             const struct btf_type *t);
 295         void (*seq_show)(const struct btf *btf, const struct btf_type *t,
 296                          u32 type_id, void *data, u8 bits_offsets,
 297                          struct seq_file *m);
 298 };
 299 
 300 static const struct btf_kind_operations * const kind_ops[NR_BTF_KINDS];
 301 static struct btf_type btf_void;
 302 
 303 static int btf_resolve(struct btf_verifier_env *env,
 304                        const struct btf_type *t, u32 type_id);
 305 
 306 static bool btf_type_is_modifier(const struct btf_type *t)
 307 {
 308         /* Some of them is not strictly a C modifier
 309          * but they are grouped into the same bucket
 310          * for BTF concern:
 311          *   A type (t) that refers to another
 312          *   type through t->type AND its size cannot
 313          *   be determined without following the t->type.
 314          *
 315          * ptr does not fall into this bucket
 316          * because its size is always sizeof(void *).
 317          */
 318         switch (BTF_INFO_KIND(t->info)) {
 319         case BTF_KIND_TYPEDEF:
 320         case BTF_KIND_VOLATILE:
 321         case BTF_KIND_CONST:
 322         case BTF_KIND_RESTRICT:
 323                 return true;
 324         }
 325 
 326         return false;
 327 }
 328 
 329 bool btf_type_is_void(const struct btf_type *t)
 330 {
 331         return t == &btf_void;
 332 }
 333 
 334 static bool btf_type_is_fwd(const struct btf_type *t)
 335 {
 336         return BTF_INFO_KIND(t->info) == BTF_KIND_FWD;
 337 }
 338 
 339 static bool btf_type_is_func(const struct btf_type *t)
 340 {
 341         return BTF_INFO_KIND(t->info) == BTF_KIND_FUNC;
 342 }
 343 
 344 static bool btf_type_is_func_proto(const struct btf_type *t)
 345 {
 346         return BTF_INFO_KIND(t->info) == BTF_KIND_FUNC_PROTO;
 347 }
 348 
 349 static bool btf_type_nosize(const struct btf_type *t)
 350 {
 351         return btf_type_is_void(t) || btf_type_is_fwd(t) ||
 352                btf_type_is_func(t) || btf_type_is_func_proto(t);
 353 }
 354 
 355 static bool btf_type_nosize_or_null(const struct btf_type *t)
 356 {
 357         return !t || btf_type_nosize(t);
 358 }
 359 
 360 /* union is only a special case of struct:
 361  * all its offsetof(member) == 0
 362  */
 363 static bool btf_type_is_struct(const struct btf_type *t)
 364 {
 365         u8 kind = BTF_INFO_KIND(t->info);
 366 
 367         return kind == BTF_KIND_STRUCT || kind == BTF_KIND_UNION;
 368 }
 369 
 370 static bool __btf_type_is_struct(const struct btf_type *t)
 371 {
 372         return BTF_INFO_KIND(t->info) == BTF_KIND_STRUCT;
 373 }
 374 
 375 static bool btf_type_is_array(const struct btf_type *t)
 376 {
 377         return BTF_INFO_KIND(t->info) == BTF_KIND_ARRAY;
 378 }
 379 
 380 static bool btf_type_is_ptr(const struct btf_type *t)
 381 {
 382         return BTF_INFO_KIND(t->info) == BTF_KIND_PTR;
 383 }
 384 
 385 static bool btf_type_is_int(const struct btf_type *t)
 386 {
 387         return BTF_INFO_KIND(t->info) == BTF_KIND_INT;
 388 }
 389 
 390 static bool btf_type_is_var(const struct btf_type *t)
 391 {
 392         return BTF_INFO_KIND(t->info) == BTF_KIND_VAR;
 393 }
 394 
 395 static bool btf_type_is_datasec(const struct btf_type *t)
 396 {
 397         return BTF_INFO_KIND(t->info) == BTF_KIND_DATASEC;
 398 }
 399 
 400 /* Types that act only as a source, not sink or intermediate
 401  * type when resolving.
 402  */
 403 static bool btf_type_is_resolve_source_only(const struct btf_type *t)
 404 {
 405         return btf_type_is_var(t) ||
 406                btf_type_is_datasec(t);
 407 }
 408 
 409 /* What types need to be resolved?
 410  *
 411  * btf_type_is_modifier() is an obvious one.
 412  *
 413  * btf_type_is_struct() because its member refers to
 414  * another type (through member->type).
 415  *
 416  * btf_type_is_var() because the variable refers to
 417  * another type. btf_type_is_datasec() holds multiple
 418  * btf_type_is_var() types that need resolving.
 419  *
 420  * btf_type_is_array() because its element (array->type)
 421  * refers to another type.  Array can be thought of a
 422  * special case of struct while array just has the same
 423  * member-type repeated by array->nelems of times.
 424  */
 425 static bool btf_type_needs_resolve(const struct btf_type *t)
 426 {
 427         return btf_type_is_modifier(t) ||
 428                btf_type_is_ptr(t) ||
 429                btf_type_is_struct(t) ||
 430                btf_type_is_array(t) ||
 431                btf_type_is_var(t) ||
 432                btf_type_is_datasec(t);
 433 }
 434 
 435 /* t->size can be used */
 436 static bool btf_type_has_size(const struct btf_type *t)
 437 {
 438         switch (BTF_INFO_KIND(t->info)) {
 439         case BTF_KIND_INT:
 440         case BTF_KIND_STRUCT:
 441         case BTF_KIND_UNION:
 442         case BTF_KIND_ENUM:
 443         case BTF_KIND_DATASEC:
 444                 return true;
 445         }
 446 
 447         return false;
 448 }
 449 
 450 static const char *btf_int_encoding_str(u8 encoding)
 451 {
 452         if (encoding == 0)
 453                 return "(none)";
 454         else if (encoding == BTF_INT_SIGNED)
 455                 return "SIGNED";
 456         else if (encoding == BTF_INT_CHAR)
 457                 return "CHAR";
 458         else if (encoding == BTF_INT_BOOL)
 459                 return "BOOL";
 460         else
 461                 return "UNKN";
 462 }
 463 
 464 static u16 btf_type_vlen(const struct btf_type *t)
 465 {
 466         return BTF_INFO_VLEN(t->info);
 467 }
 468 
 469 static bool btf_type_kflag(const struct btf_type *t)
 470 {
 471         return BTF_INFO_KFLAG(t->info);
 472 }
 473 
 474 static u32 btf_member_bit_offset(const struct btf_type *struct_type,
 475                              const struct btf_member *member)
 476 {
 477         return btf_type_kflag(struct_type) ? BTF_MEMBER_BIT_OFFSET(member->offset)
 478                                            : member->offset;
 479 }
 480 
 481 static u32 btf_member_bitfield_size(const struct btf_type *struct_type,
 482                                     const struct btf_member *member)
 483 {
 484         return btf_type_kflag(struct_type) ? BTF_MEMBER_BITFIELD_SIZE(member->offset)
 485                                            : 0;
 486 }
 487 
 488 static u32 btf_type_int(const struct btf_type *t)
 489 {
 490         return *(u32 *)(t + 1);
 491 }
 492 
 493 static const struct btf_array *btf_type_array(const struct btf_type *t)
 494 {
 495         return (const struct btf_array *)(t + 1);
 496 }
 497 
 498 static const struct btf_member *btf_type_member(const struct btf_type *t)
 499 {
 500         return (const struct btf_member *)(t + 1);
 501 }
 502 
 503 static const struct btf_enum *btf_type_enum(const struct btf_type *t)
 504 {
 505         return (const struct btf_enum *)(t + 1);
 506 }
 507 
 508 static const struct btf_var *btf_type_var(const struct btf_type *t)
 509 {
 510         return (const struct btf_var *)(t + 1);
 511 }
 512 
 513 static const struct btf_var_secinfo *btf_type_var_secinfo(const struct btf_type *t)
 514 {
 515         return (const struct btf_var_secinfo *)(t + 1);
 516 }
 517 
 518 static const struct btf_kind_operations *btf_type_ops(const struct btf_type *t)
 519 {
 520         return kind_ops[BTF_INFO_KIND(t->info)];
 521 }
 522 
 523 static bool btf_name_offset_valid(const struct btf *btf, u32 offset)
 524 {
 525         return BTF_STR_OFFSET_VALID(offset) &&
 526                 offset < btf->hdr.str_len;
 527 }
 528 
 529 static bool __btf_name_char_ok(char c, bool first, bool dot_ok)
 530 {
 531         if ((first ? !isalpha(c) :
 532                      !isalnum(c)) &&
 533             c != '_' &&
 534             ((c == '.' && !dot_ok) ||
 535               c != '.'))
 536                 return false;
 537         return true;
 538 }
 539 
 540 static bool __btf_name_valid(const struct btf *btf, u32 offset, bool dot_ok)
 541 {
 542         /* offset must be valid */
 543         const char *src = &btf->strings[offset];
 544         const char *src_limit;
 545 
 546         if (!__btf_name_char_ok(*src, true, dot_ok))
 547                 return false;
 548 
 549         /* set a limit on identifier length */
 550         src_limit = src + KSYM_NAME_LEN;
 551         src++;
 552         while (*src && src < src_limit) {
 553                 if (!__btf_name_char_ok(*src, false, dot_ok))
 554                         return false;
 555                 src++;
 556         }
 557 
 558         return !*src;
 559 }
 560 
 561 /* Only C-style identifier is permitted. This can be relaxed if
 562  * necessary.
 563  */
 564 static bool btf_name_valid_identifier(const struct btf *btf, u32 offset)
 565 {
 566         return __btf_name_valid(btf, offset, false);
 567 }
 568 
 569 static bool btf_name_valid_section(const struct btf *btf, u32 offset)
 570 {
 571         return __btf_name_valid(btf, offset, true);
 572 }
 573 
 574 static const char *__btf_name_by_offset(const struct btf *btf, u32 offset)
 575 {
 576         if (!offset)
 577                 return "(anon)";
 578         else if (offset < btf->hdr.str_len)
 579                 return &btf->strings[offset];
 580         else
 581                 return "(invalid-name-offset)";
 582 }
 583 
 584 const char *btf_name_by_offset(const struct btf *btf, u32 offset)
 585 {
 586         if (offset < btf->hdr.str_len)
 587                 return &btf->strings[offset];
 588 
 589         return NULL;
 590 }
 591 
 592 const struct btf_type *btf_type_by_id(const struct btf *btf, u32 type_id)
 593 {
 594         if (type_id > btf->nr_types)
 595                 return NULL;
 596 
 597         return btf->types[type_id];
 598 }
 599 
 600 /*
 601  * Regular int is not a bit field and it must be either
 602  * u8/u16/u32/u64 or __int128.
 603  */
 604 static bool btf_type_int_is_regular(const struct btf_type *t)
 605 {
 606         u8 nr_bits, nr_bytes;
 607         u32 int_data;
 608 
 609         int_data = btf_type_int(t);
 610         nr_bits = BTF_INT_BITS(int_data);
 611         nr_bytes = BITS_ROUNDUP_BYTES(nr_bits);
 612         if (BITS_PER_BYTE_MASKED(nr_bits) ||
 613             BTF_INT_OFFSET(int_data) ||
 614             (nr_bytes != sizeof(u8) && nr_bytes != sizeof(u16) &&
 615              nr_bytes != sizeof(u32) && nr_bytes != sizeof(u64) &&
 616              nr_bytes != (2 * sizeof(u64)))) {
 617                 return false;
 618         }
 619 
 620         return true;
 621 }
 622 
 623 /*
 624  * Check that given struct member is a regular int with expected
 625  * offset and size.
 626  */
 627 bool btf_member_is_reg_int(const struct btf *btf, const struct btf_type *s,
 628                            const struct btf_member *m,
 629                            u32 expected_offset, u32 expected_size)
 630 {
 631         const struct btf_type *t;
 632         u32 id, int_data;
 633         u8 nr_bits;
 634 
 635         id = m->type;
 636         t = btf_type_id_size(btf, &id, NULL);
 637         if (!t || !btf_type_is_int(t))
 638                 return false;
 639 
 640         int_data = btf_type_int(t);
 641         nr_bits = BTF_INT_BITS(int_data);
 642         if (btf_type_kflag(s)) {
 643                 u32 bitfield_size = BTF_MEMBER_BITFIELD_SIZE(m->offset);
 644                 u32 bit_offset = BTF_MEMBER_BIT_OFFSET(m->offset);
 645 
 646                 /* if kflag set, int should be a regular int and
 647                  * bit offset should be at byte boundary.
 648                  */
 649                 return !bitfield_size &&
 650                        BITS_ROUNDUP_BYTES(bit_offset) == expected_offset &&
 651                        BITS_ROUNDUP_BYTES(nr_bits) == expected_size;
 652         }
 653 
 654         if (BTF_INT_OFFSET(int_data) ||
 655             BITS_PER_BYTE_MASKED(m->offset) ||
 656             BITS_ROUNDUP_BYTES(m->offset) != expected_offset ||
 657             BITS_PER_BYTE_MASKED(nr_bits) ||
 658             BITS_ROUNDUP_BYTES(nr_bits) != expected_size)
 659                 return false;
 660 
 661         return true;
 662 }
 663 
 664 __printf(2, 3) static void __btf_verifier_log(struct bpf_verifier_log *log,
 665                                               const char *fmt, ...)
 666 {
 667         va_list args;
 668 
 669         va_start(args, fmt);
 670         bpf_verifier_vlog(log, fmt, args);
 671         va_end(args);
 672 }
 673 
 674 __printf(2, 3) static void btf_verifier_log(struct btf_verifier_env *env,
 675                                             const char *fmt, ...)
 676 {
 677         struct bpf_verifier_log *log = &env->log;
 678         va_list args;
 679 
 680         if (!bpf_verifier_log_needed(log))
 681                 return;
 682 
 683         va_start(args, fmt);
 684         bpf_verifier_vlog(log, fmt, args);
 685         va_end(args);
 686 }
 687 
 688 __printf(4, 5) static void __btf_verifier_log_type(struct btf_verifier_env *env,
 689                                                    const struct btf_type *t,
 690                                                    bool log_details,
 691                                                    const char *fmt, ...)
 692 {
 693         struct bpf_verifier_log *log = &env->log;
 694         u8 kind = BTF_INFO_KIND(t->info);
 695         struct btf *btf = env->btf;
 696         va_list args;
 697 
 698         if (!bpf_verifier_log_needed(log))
 699                 return;
 700 
 701         __btf_verifier_log(log, "[%u] %s %s%s",
 702                            env->log_type_id,
 703                            btf_kind_str[kind],
 704                            __btf_name_by_offset(btf, t->name_off),
 705                            log_details ? " " : "");
 706 
 707         if (log_details)
 708                 btf_type_ops(t)->log_details(env, t);
 709 
 710         if (fmt && *fmt) {
 711                 __btf_verifier_log(log, " ");
 712                 va_start(args, fmt);
 713                 bpf_verifier_vlog(log, fmt, args);
 714                 va_end(args);
 715         }
 716 
 717         __btf_verifier_log(log, "\n");
 718 }
 719 
 720 #define btf_verifier_log_type(env, t, ...) \
 721         __btf_verifier_log_type((env), (t), true, __VA_ARGS__)
 722 #define btf_verifier_log_basic(env, t, ...) \
 723         __btf_verifier_log_type((env), (t), false, __VA_ARGS__)
 724 
 725 __printf(4, 5)
 726 static void btf_verifier_log_member(struct btf_verifier_env *env,
 727                                     const struct btf_type *struct_type,
 728                                     const struct btf_member *member,
 729                                     const char *fmt, ...)
 730 {
 731         struct bpf_verifier_log *log = &env->log;
 732         struct btf *btf = env->btf;
 733         va_list args;
 734 
 735         if (!bpf_verifier_log_needed(log))
 736                 return;
 737 
 738         /* The CHECK_META phase already did a btf dump.
 739          *
 740          * If member is logged again, it must hit an error in
 741          * parsing this member.  It is useful to print out which
 742          * struct this member belongs to.
 743          */
 744         if (env->phase != CHECK_META)
 745                 btf_verifier_log_type(env, struct_type, NULL);
 746 
 747         if (btf_type_kflag(struct_type))
 748                 __btf_verifier_log(log,
 749                                    "\t%s type_id=%u bitfield_size=%u bits_offset=%u",
 750                                    __btf_name_by_offset(btf, member->name_off),
 751                                    member->type,
 752                                    BTF_MEMBER_BITFIELD_SIZE(member->offset),
 753                                    BTF_MEMBER_BIT_OFFSET(member->offset));
 754         else
 755                 __btf_verifier_log(log, "\t%s type_id=%u bits_offset=%u",
 756                                    __btf_name_by_offset(btf, member->name_off),
 757                                    member->type, member->offset);
 758 
 759         if (fmt && *fmt) {
 760                 __btf_verifier_log(log, " ");
 761                 va_start(args, fmt);
 762                 bpf_verifier_vlog(log, fmt, args);
 763                 va_end(args);
 764         }
 765 
 766         __btf_verifier_log(log, "\n");
 767 }
 768 
 769 __printf(4, 5)
 770 static void btf_verifier_log_vsi(struct btf_verifier_env *env,
 771                                  const struct btf_type *datasec_type,
 772                                  const struct btf_var_secinfo *vsi,
 773                                  const char *fmt, ...)
 774 {
 775         struct bpf_verifier_log *log = &env->log;
 776         va_list args;
 777 
 778         if (!bpf_verifier_log_needed(log))
 779                 return;
 780         if (env->phase != CHECK_META)
 781                 btf_verifier_log_type(env, datasec_type, NULL);
 782 
 783         __btf_verifier_log(log, "\t type_id=%u offset=%u size=%u",
 784                            vsi->type, vsi->offset, vsi->size);
 785         if (fmt && *fmt) {
 786                 __btf_verifier_log(log, " ");
 787                 va_start(args, fmt);
 788                 bpf_verifier_vlog(log, fmt, args);
 789                 va_end(args);
 790         }
 791 
 792         __btf_verifier_log(log, "\n");
 793 }
 794 
 795 static void btf_verifier_log_hdr(struct btf_verifier_env *env,
 796                                  u32 btf_data_size)
 797 {
 798         struct bpf_verifier_log *log = &env->log;
 799         const struct btf *btf = env->btf;
 800         const struct btf_header *hdr;
 801 
 802         if (!bpf_verifier_log_needed(log))
 803                 return;
 804 
 805         hdr = &btf->hdr;
 806         __btf_verifier_log(log, "magic: 0x%x\n", hdr->magic);
 807         __btf_verifier_log(log, "version: %u\n", hdr->version);
 808         __btf_verifier_log(log, "flags: 0x%x\n", hdr->flags);
 809         __btf_verifier_log(log, "hdr_len: %u\n", hdr->hdr_len);
 810         __btf_verifier_log(log, "type_off: %u\n", hdr->type_off);
 811         __btf_verifier_log(log, "type_len: %u\n", hdr->type_len);
 812         __btf_verifier_log(log, "str_off: %u\n", hdr->str_off);
 813         __btf_verifier_log(log, "str_len: %u\n", hdr->str_len);
 814         __btf_verifier_log(log, "btf_total_size: %u\n", btf_data_size);
 815 }
 816 
 817 static int btf_add_type(struct btf_verifier_env *env, struct btf_type *t)
 818 {
 819         struct btf *btf = env->btf;
 820 
 821         /* < 2 because +1 for btf_void which is always in btf->types[0].
 822          * btf_void is not accounted in btf->nr_types because btf_void
 823          * does not come from the BTF file.
 824          */
 825         if (btf->types_size - btf->nr_types < 2) {
 826                 /* Expand 'types' array */
 827 
 828                 struct btf_type **new_types;
 829                 u32 expand_by, new_size;
 830 
 831                 if (btf->types_size == BTF_MAX_TYPE) {
 832                         btf_verifier_log(env, "Exceeded max num of types");
 833                         return -E2BIG;
 834                 }
 835 
 836                 expand_by = max_t(u32, btf->types_size >> 2, 16);
 837                 new_size = min_t(u32, BTF_MAX_TYPE,
 838                                  btf->types_size + expand_by);
 839 
 840                 new_types = kvcalloc(new_size, sizeof(*new_types),
 841                                      GFP_KERNEL | __GFP_NOWARN);
 842                 if (!new_types)
 843                         return -ENOMEM;
 844 
 845                 if (btf->nr_types == 0)
 846                         new_types[0] = &btf_void;
 847                 else
 848                         memcpy(new_types, btf->types,
 849                                sizeof(*btf->types) * (btf->nr_types + 1));
 850 
 851                 kvfree(btf->types);
 852                 btf->types = new_types;
 853                 btf->types_size = new_size;
 854         }
 855 
 856         btf->types[++(btf->nr_types)] = t;
 857 
 858         return 0;
 859 }
 860 
 861 static int btf_alloc_id(struct btf *btf)
 862 {
 863         int id;
 864 
 865         idr_preload(GFP_KERNEL);
 866         spin_lock_bh(&btf_idr_lock);
 867         id = idr_alloc_cyclic(&btf_idr, btf, 1, INT_MAX, GFP_ATOMIC);
 868         if (id > 0)
 869                 btf->id = id;
 870         spin_unlock_bh(&btf_idr_lock);
 871         idr_preload_end();
 872 
 873         if (WARN_ON_ONCE(!id))
 874                 return -ENOSPC;
 875 
 876         return id > 0 ? 0 : id;
 877 }
 878 
 879 static void btf_free_id(struct btf *btf)
 880 {
 881         unsigned long flags;
 882 
 883         /*
 884          * In map-in-map, calling map_delete_elem() on outer
 885          * map will call bpf_map_put on the inner map.
 886          * It will then eventually call btf_free_id()
 887          * on the inner map.  Some of the map_delete_elem()
 888          * implementation may have irq disabled, so
 889          * we need to use the _irqsave() version instead
 890          * of the _bh() version.
 891          */
 892         spin_lock_irqsave(&btf_idr_lock, flags);
 893         idr_remove(&btf_idr, btf->id);
 894         spin_unlock_irqrestore(&btf_idr_lock, flags);
 895 }
 896 
 897 static void btf_free(struct btf *btf)
 898 {
 899         kvfree(btf->types);
 900         kvfree(btf->resolved_sizes);
 901         kvfree(btf->resolved_ids);
 902         kvfree(btf->data);
 903         kfree(btf);
 904 }
 905 
 906 static void btf_free_rcu(struct rcu_head *rcu)
 907 {
 908         struct btf *btf = container_of(rcu, struct btf, rcu);
 909 
 910         btf_free(btf);
 911 }
 912 
 913 void btf_put(struct btf *btf)
 914 {
 915         if (btf && refcount_dec_and_test(&btf->refcnt)) {
 916                 btf_free_id(btf);
 917                 call_rcu(&btf->rcu, btf_free_rcu);
 918         }
 919 }
 920 
 921 static int env_resolve_init(struct btf_verifier_env *env)
 922 {
 923         struct btf *btf = env->btf;
 924         u32 nr_types = btf->nr_types;
 925         u32 *resolved_sizes = NULL;
 926         u32 *resolved_ids = NULL;
 927         u8 *visit_states = NULL;
 928 
 929         /* +1 for btf_void */
 930         resolved_sizes = kvcalloc(nr_types + 1, sizeof(*resolved_sizes),
 931                                   GFP_KERNEL | __GFP_NOWARN);
 932         if (!resolved_sizes)
 933                 goto nomem;
 934 
 935         resolved_ids = kvcalloc(nr_types + 1, sizeof(*resolved_ids),
 936                                 GFP_KERNEL | __GFP_NOWARN);
 937         if (!resolved_ids)
 938                 goto nomem;
 939 
 940         visit_states = kvcalloc(nr_types + 1, sizeof(*visit_states),
 941                                 GFP_KERNEL | __GFP_NOWARN);
 942         if (!visit_states)
 943                 goto nomem;
 944 
 945         btf->resolved_sizes = resolved_sizes;
 946         btf->resolved_ids = resolved_ids;
 947         env->visit_states = visit_states;
 948 
 949         return 0;
 950 
 951 nomem:
 952         kvfree(resolved_sizes);
 953         kvfree(resolved_ids);
 954         kvfree(visit_states);
 955         return -ENOMEM;
 956 }
 957 
 958 static void btf_verifier_env_free(struct btf_verifier_env *env)
 959 {
 960         kvfree(env->visit_states);
 961         kfree(env);
 962 }
 963 
 964 static bool env_type_is_resolve_sink(const struct btf_verifier_env *env,
 965                                      const struct btf_type *next_type)
 966 {
 967         switch (env->resolve_mode) {
 968         case RESOLVE_TBD:
 969                 /* int, enum or void is a sink */
 970                 return !btf_type_needs_resolve(next_type);
 971         case RESOLVE_PTR:
 972                 /* int, enum, void, struct, array, func or func_proto is a sink
 973                  * for ptr
 974                  */
 975                 return !btf_type_is_modifier(next_type) &&
 976                         !btf_type_is_ptr(next_type);
 977         case RESOLVE_STRUCT_OR_ARRAY:
 978                 /* int, enum, void, ptr, func or func_proto is a sink
 979                  * for struct and array
 980                  */
 981                 return !btf_type_is_modifier(next_type) &&
 982                         !btf_type_is_array(next_type) &&
 983                         !btf_type_is_struct(next_type);
 984         default:
 985                 BUG();
 986         }
 987 }
 988 
 989 static bool env_type_is_resolved(const struct btf_verifier_env *env,
 990                                  u32 type_id)
 991 {
 992         return env->visit_states[type_id] == RESOLVED;
 993 }
 994 
 995 static int env_stack_push(struct btf_verifier_env *env,
 996                           const struct btf_type *t, u32 type_id)
 997 {
 998         struct resolve_vertex *v;
 999 
1000         if (env->top_stack == MAX_RESOLVE_DEPTH)
1001                 return -E2BIG;
1002 
1003         if (env->visit_states[type_id] != NOT_VISITED)
1004                 return -EEXIST;
1005 
1006         env->visit_states[type_id] = VISITED;
1007 
1008         v = &env->stack[env->top_stack++];
1009         v->t = t;
1010         v->type_id = type_id;
1011         v->next_member = 0;
1012 
1013         if (env->resolve_mode == RESOLVE_TBD) {
1014                 if (btf_type_is_ptr(t))
1015                         env->resolve_mode = RESOLVE_PTR;
1016                 else if (btf_type_is_struct(t) || btf_type_is_array(t))
1017                         env->resolve_mode = RESOLVE_STRUCT_OR_ARRAY;
1018         }
1019 
1020         return 0;
1021 }
1022 
1023 static void env_stack_set_next_member(struct btf_verifier_env *env,
1024                                       u16 next_member)
1025 {
1026         env->stack[env->top_stack - 1].next_member = next_member;
1027 }
1028 
1029 static void env_stack_pop_resolved(struct btf_verifier_env *env,
1030                                    u32 resolved_type_id,
1031                                    u32 resolved_size)
1032 {
1033         u32 type_id = env->stack[--(env->top_stack)].type_id;
1034         struct btf *btf = env->btf;
1035 
1036         btf->resolved_sizes[type_id] = resolved_size;
1037         btf->resolved_ids[type_id] = resolved_type_id;
1038         env->visit_states[type_id] = RESOLVED;
1039 }
1040 
1041 static const struct resolve_vertex *env_stack_peak(struct btf_verifier_env *env)
1042 {
1043         return env->top_stack ? &env->stack[env->top_stack - 1] : NULL;
1044 }
1045 
1046 /* The input param "type_id" must point to a needs_resolve type */
1047 static const struct btf_type *btf_type_id_resolve(const struct btf *btf,
1048                                                   u32 *type_id)
1049 {
1050         *type_id = btf->resolved_ids[*type_id];
1051         return btf_type_by_id(btf, *type_id);
1052 }
1053 
1054 const struct btf_type *btf_type_id_size(const struct btf *btf,
1055                                         u32 *type_id, u32 *ret_size)
1056 {
1057         const struct btf_type *size_type;
1058         u32 size_type_id = *type_id;
1059         u32 size = 0;
1060 
1061         size_type = btf_type_by_id(btf, size_type_id);
1062         if (btf_type_nosize_or_null(size_type))
1063                 return NULL;
1064 
1065         if (btf_type_has_size(size_type)) {
1066                 size = size_type->size;
1067         } else if (btf_type_is_array(size_type)) {
1068                 size = btf->resolved_sizes[size_type_id];
1069         } else if (btf_type_is_ptr(size_type)) {
1070                 size = sizeof(void *);
1071         } else {
1072                 if (WARN_ON_ONCE(!btf_type_is_modifier(size_type) &&
1073                                  !btf_type_is_var(size_type)))
1074                         return NULL;
1075 
1076                 size_type_id = btf->resolved_ids[size_type_id];
1077                 size_type = btf_type_by_id(btf, size_type_id);
1078                 if (btf_type_nosize_or_null(size_type))
1079                         return NULL;
1080                 else if (btf_type_has_size(size_type))
1081                         size = size_type->size;
1082                 else if (btf_type_is_array(size_type))
1083                         size = btf->resolved_sizes[size_type_id];
1084                 else if (btf_type_is_ptr(size_type))
1085                         size = sizeof(void *);
1086                 else
1087                         return NULL;
1088         }
1089 
1090         *type_id = size_type_id;
1091         if (ret_size)
1092                 *ret_size = size;
1093 
1094         return size_type;
1095 }
1096 
1097 static int btf_df_check_member(struct btf_verifier_env *env,
1098                                const struct btf_type *struct_type,
1099                                const struct btf_member *member,
1100                                const struct btf_type *member_type)
1101 {
1102         btf_verifier_log_basic(env, struct_type,
1103                                "Unsupported check_member");
1104         return -EINVAL;
1105 }
1106 
1107 static int btf_df_check_kflag_member(struct btf_verifier_env *env,
1108                                      const struct btf_type *struct_type,
1109                                      const struct btf_member *member,
1110                                      const struct btf_type *member_type)
1111 {
1112         btf_verifier_log_basic(env, struct_type,
1113                                "Unsupported check_kflag_member");
1114         return -EINVAL;
1115 }
1116 
1117 /* Used for ptr, array and struct/union type members.
1118  * int, enum and modifier types have their specific callback functions.
1119  */
1120 static int btf_generic_check_kflag_member(struct btf_verifier_env *env,
1121                                           const struct btf_type *struct_type,
1122                                           const struct btf_member *member,
1123                                           const struct btf_type *member_type)
1124 {
1125         if (BTF_MEMBER_BITFIELD_SIZE(member->offset)) {
1126                 btf_verifier_log_member(env, struct_type, member,
1127                                         "Invalid member bitfield_size");
1128                 return -EINVAL;
1129         }
1130 
1131         /* bitfield size is 0, so member->offset represents bit offset only.
1132          * It is safe to call non kflag check_member variants.
1133          */
1134         return btf_type_ops(member_type)->check_member(env, struct_type,
1135                                                        member,
1136                                                        member_type);
1137 }
1138 
1139 static int btf_df_resolve(struct btf_verifier_env *env,
1140                           const struct resolve_vertex *v)
1141 {
1142         btf_verifier_log_basic(env, v->t, "Unsupported resolve");
1143         return -EINVAL;
1144 }
1145 
1146 static void btf_df_seq_show(const struct btf *btf, const struct btf_type *t,
1147                             u32 type_id, void *data, u8 bits_offsets,
1148                             struct seq_file *m)
1149 {
1150         seq_printf(m, "<unsupported kind:%u>", BTF_INFO_KIND(t->info));
1151 }
1152 
1153 static int btf_int_check_member(struct btf_verifier_env *env,
1154                                 const struct btf_type *struct_type,
1155                                 const struct btf_member *member,
1156                                 const struct btf_type *member_type)
1157 {
1158         u32 int_data = btf_type_int(member_type);
1159         u32 struct_bits_off = member->offset;
1160         u32 struct_size = struct_type->size;
1161         u32 nr_copy_bits;
1162         u32 bytes_offset;
1163 
1164         if (U32_MAX - struct_bits_off < BTF_INT_OFFSET(int_data)) {
1165                 btf_verifier_log_member(env, struct_type, member,
1166                                         "bits_offset exceeds U32_MAX");
1167                 return -EINVAL;
1168         }
1169 
1170         struct_bits_off += BTF_INT_OFFSET(int_data);
1171         bytes_offset = BITS_ROUNDDOWN_BYTES(struct_bits_off);
1172         nr_copy_bits = BTF_INT_BITS(int_data) +
1173                 BITS_PER_BYTE_MASKED(struct_bits_off);
1174 
1175         if (nr_copy_bits > BITS_PER_U128) {
1176                 btf_verifier_log_member(env, struct_type, member,
1177                                         "nr_copy_bits exceeds 128");
1178                 return -EINVAL;
1179         }
1180 
1181         if (struct_size < bytes_offset ||
1182             struct_size - bytes_offset < BITS_ROUNDUP_BYTES(nr_copy_bits)) {
1183                 btf_verifier_log_member(env, struct_type, member,
1184                                         "Member exceeds struct_size");
1185                 return -EINVAL;
1186         }
1187 
1188         return 0;
1189 }
1190 
1191 static int btf_int_check_kflag_member(struct btf_verifier_env *env,
1192                                       const struct btf_type *struct_type,
1193                                       const struct btf_member *member,
1194                                       const struct btf_type *member_type)
1195 {
1196         u32 struct_bits_off, nr_bits, nr_int_data_bits, bytes_offset;
1197         u32 int_data = btf_type_int(member_type);
1198         u32 struct_size = struct_type->size;
1199         u32 nr_copy_bits;
1200 
1201         /* a regular int type is required for the kflag int member */
1202         if (!btf_type_int_is_regular(member_type)) {
1203                 btf_verifier_log_member(env, struct_type, member,
1204                                         "Invalid member base type");
1205                 return -EINVAL;
1206         }
1207 
1208         /* check sanity of bitfield size */
1209         nr_bits = BTF_MEMBER_BITFIELD_SIZE(member->offset);
1210         struct_bits_off = BTF_MEMBER_BIT_OFFSET(member->offset);
1211         nr_int_data_bits = BTF_INT_BITS(int_data);
1212         if (!nr_bits) {
1213                 /* Not a bitfield member, member offset must be at byte
1214                  * boundary.
1215                  */
1216                 if (BITS_PER_BYTE_MASKED(struct_bits_off)) {
1217                         btf_verifier_log_member(env, struct_type, member,
1218                                                 "Invalid member offset");
1219                         return -EINVAL;
1220                 }
1221 
1222                 nr_bits = nr_int_data_bits;
1223         } else if (nr_bits > nr_int_data_bits) {
1224                 btf_verifier_log_member(env, struct_type, member,
1225                                         "Invalid member bitfield_size");
1226                 return -EINVAL;
1227         }
1228 
1229         bytes_offset = BITS_ROUNDDOWN_BYTES(struct_bits_off);
1230         nr_copy_bits = nr_bits + BITS_PER_BYTE_MASKED(struct_bits_off);
1231         if (nr_copy_bits > BITS_PER_U128) {
1232                 btf_verifier_log_member(env, struct_type, member,
1233                                         "nr_copy_bits exceeds 128");
1234                 return -EINVAL;
1235         }
1236 
1237         if (struct_size < bytes_offset ||
1238             struct_size - bytes_offset < BITS_ROUNDUP_BYTES(nr_copy_bits)) {
1239                 btf_verifier_log_member(env, struct_type, member,
1240                                         "Member exceeds struct_size");
1241                 return -EINVAL;
1242         }
1243 
1244         return 0;
1245 }
1246 
1247 static s32 btf_int_check_meta(struct btf_verifier_env *env,
1248                               const struct btf_type *t,
1249                               u32 meta_left)
1250 {
1251         u32 int_data, nr_bits, meta_needed = sizeof(int_data);
1252         u16 encoding;
1253 
1254         if (meta_left < meta_needed) {
1255                 btf_verifier_log_basic(env, t,
1256                                        "meta_left:%u meta_needed:%u",
1257                                        meta_left, meta_needed);
1258                 return -EINVAL;
1259         }
1260 
1261         if (btf_type_vlen(t)) {
1262                 btf_verifier_log_type(env, t, "vlen != 0");
1263                 return -EINVAL;
1264         }
1265 
1266         if (btf_type_kflag(t)) {
1267                 btf_verifier_log_type(env, t, "Invalid btf_info kind_flag");
1268                 return -EINVAL;
1269         }
1270 
1271         int_data = btf_type_int(t);
1272         if (int_data & ~BTF_INT_MASK) {
1273                 btf_verifier_log_basic(env, t, "Invalid int_data:%x",
1274                                        int_data);
1275                 return -EINVAL;
1276         }
1277 
1278         nr_bits = BTF_INT_BITS(int_data) + BTF_INT_OFFSET(int_data);
1279 
1280         if (nr_bits > BITS_PER_U128) {
1281                 btf_verifier_log_type(env, t, "nr_bits exceeds %zu",
1282                                       BITS_PER_U128);
1283                 return -EINVAL;
1284         }
1285 
1286         if (BITS_ROUNDUP_BYTES(nr_bits) > t->size) {
1287                 btf_verifier_log_type(env, t, "nr_bits exceeds type_size");
1288                 return -EINVAL;
1289         }
1290 
1291         /*
1292          * Only one of the encoding bits is allowed and it
1293          * should be sufficient for the pretty print purpose (i.e. decoding).
1294          * Multiple bits can be allowed later if it is found
1295          * to be insufficient.
1296          */
1297         encoding = BTF_INT_ENCODING(int_data);
1298         if (encoding &&
1299             encoding != BTF_INT_SIGNED &&
1300             encoding != BTF_INT_CHAR &&
1301             encoding != BTF_INT_BOOL) {
1302                 btf_verifier_log_type(env, t, "Unsupported encoding");
1303                 return -ENOTSUPP;
1304         }
1305 
1306         btf_verifier_log_type(env, t, NULL);
1307 
1308         return meta_needed;
1309 }
1310 
1311 static void btf_int_log(struct btf_verifier_env *env,
1312                         const struct btf_type *t)
1313 {
1314         int int_data = btf_type_int(t);
1315 
1316         btf_verifier_log(env,
1317                          "size=%u bits_offset=%u nr_bits=%u encoding=%s",
1318                          t->size, BTF_INT_OFFSET(int_data),
1319                          BTF_INT_BITS(int_data),
1320                          btf_int_encoding_str(BTF_INT_ENCODING(int_data)));
1321 }
1322 
1323 static void btf_int128_print(struct seq_file *m, void *data)
1324 {
1325         /* data points to a __int128 number.
1326          * Suppose
1327          *     int128_num = *(__int128 *)data;
1328          * The below formulas shows what upper_num and lower_num represents:
1329          *     upper_num = int128_num >> 64;
1330          *     lower_num = int128_num & 0xffffffffFFFFFFFFULL;
1331          */
1332         u64 upper_num, lower_num;
1333 
1334 #ifdef __BIG_ENDIAN_BITFIELD
1335         upper_num = *(u64 *)data;
1336         lower_num = *(u64 *)(data + 8);
1337 #else
1338         upper_num = *(u64 *)(data + 8);
1339         lower_num = *(u64 *)data;
1340 #endif
1341         if (upper_num == 0)
1342                 seq_printf(m, "0x%llx", lower_num);
1343         else
1344                 seq_printf(m, "0x%llx%016llx", upper_num, lower_num);
1345 }
1346 
1347 static void btf_int128_shift(u64 *print_num, u16 left_shift_bits,
1348                              u16 right_shift_bits)
1349 {
1350         u64 upper_num, lower_num;
1351 
1352 #ifdef __BIG_ENDIAN_BITFIELD
1353         upper_num = print_num[0];
1354         lower_num = print_num[1];
1355 #else
1356         upper_num = print_num[1];
1357         lower_num = print_num[0];
1358 #endif
1359 
1360         /* shake out un-needed bits by shift/or operations */
1361         if (left_shift_bits >= 64) {
1362                 upper_num = lower_num << (left_shift_bits - 64);
1363                 lower_num = 0;
1364         } else {
1365                 upper_num = (upper_num << left_shift_bits) |
1366                             (lower_num >> (64 - left_shift_bits));
1367                 lower_num = lower_num << left_shift_bits;
1368         }
1369 
1370         if (right_shift_bits >= 64) {
1371                 lower_num = upper_num >> (right_shift_bits - 64);
1372                 upper_num = 0;
1373         } else {
1374                 lower_num = (lower_num >> right_shift_bits) |
1375                             (upper_num << (64 - right_shift_bits));
1376                 upper_num = upper_num >> right_shift_bits;
1377         }
1378 
1379 #ifdef __BIG_ENDIAN_BITFIELD
1380         print_num[0] = upper_num;
1381         print_num[1] = lower_num;
1382 #else
1383         print_num[0] = lower_num;
1384         print_num[1] = upper_num;
1385 #endif
1386 }
1387 
1388 static void btf_bitfield_seq_show(void *data, u8 bits_offset,
1389                                   u8 nr_bits, struct seq_file *m)
1390 {
1391         u16 left_shift_bits, right_shift_bits;
1392         u8 nr_copy_bytes;
1393         u8 nr_copy_bits;
1394         u64 print_num[2] = {};
1395 
1396         nr_copy_bits = nr_bits + bits_offset;
1397         nr_copy_bytes = BITS_ROUNDUP_BYTES(nr_copy_bits);
1398 
1399         memcpy(print_num, data, nr_copy_bytes);
1400 
1401 #ifdef __BIG_ENDIAN_BITFIELD
1402         left_shift_bits = bits_offset;
1403 #else
1404         left_shift_bits = BITS_PER_U128 - nr_copy_bits;
1405 #endif
1406         right_shift_bits = BITS_PER_U128 - nr_bits;
1407 
1408         btf_int128_shift(print_num, left_shift_bits, right_shift_bits);
1409         btf_int128_print(m, print_num);
1410 }
1411 
1412 
1413 static void btf_int_bits_seq_show(const struct btf *btf,
1414                                   const struct btf_type *t,
1415                                   void *data, u8 bits_offset,
1416                                   struct seq_file *m)
1417 {
1418         u32 int_data = btf_type_int(t);
1419         u8 nr_bits = BTF_INT_BITS(int_data);
1420         u8 total_bits_offset;
1421 
1422         /*
1423          * bits_offset is at most 7.
1424          * BTF_INT_OFFSET() cannot exceed 128 bits.
1425          */
1426         total_bits_offset = bits_offset + BTF_INT_OFFSET(int_data);
1427         data += BITS_ROUNDDOWN_BYTES(total_bits_offset);
1428         bits_offset = BITS_PER_BYTE_MASKED(total_bits_offset);
1429         btf_bitfield_seq_show(data, bits_offset, nr_bits, m);
1430 }
1431 
1432 static void btf_int_seq_show(const struct btf *btf, const struct btf_type *t,
1433                              u32 type_id, void *data, u8 bits_offset,
1434                              struct seq_file *m)
1435 {
1436         u32 int_data = btf_type_int(t);
1437         u8 encoding = BTF_INT_ENCODING(int_data);
1438         bool sign = encoding & BTF_INT_SIGNED;
1439         u8 nr_bits = BTF_INT_BITS(int_data);
1440 
1441         if (bits_offset || BTF_INT_OFFSET(int_data) ||
1442             BITS_PER_BYTE_MASKED(nr_bits)) {
1443                 btf_int_bits_seq_show(btf, t, data, bits_offset, m);
1444                 return;
1445         }
1446 
1447         switch (nr_bits) {
1448         case 128:
1449                 btf_int128_print(m, data);
1450                 break;
1451         case 64:
1452                 if (sign)
1453                         seq_printf(m, "%lld", *(s64 *)data);
1454                 else
1455                         seq_printf(m, "%llu", *(u64 *)data);
1456                 break;
1457         case 32:
1458                 if (sign)
1459                         seq_printf(m, "%d", *(s32 *)data);
1460                 else
1461                         seq_printf(m, "%u", *(u32 *)data);
1462                 break;
1463         case 16:
1464                 if (sign)
1465                         seq_printf(m, "%d", *(s16 *)data);
1466                 else
1467                         seq_printf(m, "%u", *(u16 *)data);
1468                 break;
1469         case 8:
1470                 if (sign)
1471                         seq_printf(m, "%d", *(s8 *)data);
1472                 else
1473                         seq_printf(m, "%u", *(u8 *)data);
1474                 break;
1475         default:
1476                 btf_int_bits_seq_show(btf, t, data, bits_offset, m);
1477         }
1478 }
1479 
1480 static const struct btf_kind_operations int_ops = {
1481         .check_meta = btf_int_check_meta,
1482         .resolve = btf_df_resolve,
1483         .check_member = btf_int_check_member,
1484         .check_kflag_member = btf_int_check_kflag_member,
1485         .log_details = btf_int_log,
1486         .seq_show = btf_int_seq_show,
1487 };
1488 
1489 static int btf_modifier_check_member(struct btf_verifier_env *env,
1490                                      const struct btf_type *struct_type,
1491                                      const struct btf_member *member,
1492                                      const struct btf_type *member_type)
1493 {
1494         const struct btf_type *resolved_type;
1495         u32 resolved_type_id = member->type;
1496         struct btf_member resolved_member;
1497         struct btf *btf = env->btf;
1498 
1499         resolved_type = btf_type_id_size(btf, &resolved_type_id, NULL);
1500         if (!resolved_type) {
1501                 btf_verifier_log_member(env, struct_type, member,
1502                                         "Invalid member");
1503                 return -EINVAL;
1504         }
1505 
1506         resolved_member = *member;
1507         resolved_member.type = resolved_type_id;
1508 
1509         return btf_type_ops(resolved_type)->check_member(env, struct_type,
1510                                                          &resolved_member,
1511                                                          resolved_type);
1512 }
1513 
1514 static int btf_modifier_check_kflag_member(struct btf_verifier_env *env,
1515                                            const struct btf_type *struct_type,
1516                                            const struct btf_member *member,
1517                                            const struct btf_type *member_type)
1518 {
1519         const struct btf_type *resolved_type;
1520         u32 resolved_type_id = member->type;
1521         struct btf_member resolved_member;
1522         struct btf *btf = env->btf;
1523 
1524         resolved_type = btf_type_id_size(btf, &resolved_type_id, NULL);
1525         if (!resolved_type) {
1526                 btf_verifier_log_member(env, struct_type, member,
1527                                         "Invalid member");
1528                 return -EINVAL;
1529         }
1530 
1531         resolved_member = *member;
1532         resolved_member.type = resolved_type_id;
1533 
1534         return btf_type_ops(resolved_type)->check_kflag_member(env, struct_type,
1535                                                                &resolved_member,
1536                                                                resolved_type);
1537 }
1538 
1539 static int btf_ptr_check_member(struct btf_verifier_env *env,
1540                                 const struct btf_type *struct_type,
1541                                 const struct btf_member *member,
1542                                 const struct btf_type *member_type)
1543 {
1544         u32 struct_size, struct_bits_off, bytes_offset;
1545 
1546         struct_size = struct_type->size;
1547         struct_bits_off = member->offset;
1548         bytes_offset = BITS_ROUNDDOWN_BYTES(struct_bits_off);
1549 
1550         if (BITS_PER_BYTE_MASKED(struct_bits_off)) {
1551                 btf_verifier_log_member(env, struct_type, member,
1552                                         "Member is not byte aligned");
1553                 return -EINVAL;
1554         }
1555 
1556         if (struct_size - bytes_offset < sizeof(void *)) {
1557                 btf_verifier_log_member(env, struct_type, member,
1558                                         "Member exceeds struct_size");
1559                 return -EINVAL;
1560         }
1561 
1562         return 0;
1563 }
1564 
1565 static int btf_ref_type_check_meta(struct btf_verifier_env *env,
1566                                    const struct btf_type *t,
1567                                    u32 meta_left)
1568 {
1569         if (btf_type_vlen(t)) {
1570                 btf_verifier_log_type(env, t, "vlen != 0");
1571                 return -EINVAL;
1572         }
1573 
1574         if (btf_type_kflag(t)) {
1575                 btf_verifier_log_type(env, t, "Invalid btf_info kind_flag");
1576                 return -EINVAL;
1577         }
1578 
1579         if (!BTF_TYPE_ID_VALID(t->type)) {
1580                 btf_verifier_log_type(env, t, "Invalid type_id");
1581                 return -EINVAL;
1582         }
1583 
1584         /* typedef type must have a valid name, and other ref types,
1585          * volatile, const, restrict, should have a null name.
1586          */
1587         if (BTF_INFO_KIND(t->info) == BTF_KIND_TYPEDEF) {
1588                 if (!t->name_off ||
1589                     !btf_name_valid_identifier(env->btf, t->name_off)) {
1590                         btf_verifier_log_type(env, t, "Invalid name");
1591                         return -EINVAL;
1592                 }
1593         } else {
1594                 if (t->name_off) {
1595                         btf_verifier_log_type(env, t, "Invalid name");
1596                         return -EINVAL;
1597                 }
1598         }
1599 
1600         btf_verifier_log_type(env, t, NULL);
1601 
1602         return 0;
1603 }
1604 
1605 static int btf_modifier_resolve(struct btf_verifier_env *env,
1606                                 const struct resolve_vertex *v)
1607 {
1608         const struct btf_type *t = v->t;
1609         const struct btf_type *next_type;
1610         u32 next_type_id = t->type;
1611         struct btf *btf = env->btf;
1612 
1613         next_type = btf_type_by_id(btf, next_type_id);
1614         if (!next_type || btf_type_is_resolve_source_only(next_type)) {
1615                 btf_verifier_log_type(env, v->t, "Invalid type_id");
1616                 return -EINVAL;
1617         }
1618 
1619         if (!env_type_is_resolve_sink(env, next_type) &&
1620             !env_type_is_resolved(env, next_type_id))
1621                 return env_stack_push(env, next_type, next_type_id);
1622 
1623         /* Figure out the resolved next_type_id with size.
1624          * They will be stored in the current modifier's
1625          * resolved_ids and resolved_sizes such that it can
1626          * save us a few type-following when we use it later (e.g. in
1627          * pretty print).
1628          */
1629         if (!btf_type_id_size(btf, &next_type_id, NULL)) {
1630                 if (env_type_is_resolved(env, next_type_id))
1631                         next_type = btf_type_id_resolve(btf, &next_type_id);
1632 
1633                 /* "typedef void new_void", "const void"...etc */
1634                 if (!btf_type_is_void(next_type) &&
1635                     !btf_type_is_fwd(next_type) &&
1636                     !btf_type_is_func_proto(next_type)) {
1637                         btf_verifier_log_type(env, v->t, "Invalid type_id");
1638                         return -EINVAL;
1639                 }
1640         }
1641 
1642         env_stack_pop_resolved(env, next_type_id, 0);
1643 
1644         return 0;
1645 }
1646 
1647 static int btf_var_resolve(struct btf_verifier_env *env,
1648                            const struct resolve_vertex *v)
1649 {
1650         const struct btf_type *next_type;
1651         const struct btf_type *t = v->t;
1652         u32 next_type_id = t->type;
1653         struct btf *btf = env->btf;
1654 
1655         next_type = btf_type_by_id(btf, next_type_id);
1656         if (!next_type || btf_type_is_resolve_source_only(next_type)) {
1657                 btf_verifier_log_type(env, v->t, "Invalid type_id");
1658                 return -EINVAL;
1659         }
1660 
1661         if (!env_type_is_resolve_sink(env, next_type) &&
1662             !env_type_is_resolved(env, next_type_id))
1663                 return env_stack_push(env, next_type, next_type_id);
1664 
1665         if (btf_type_is_modifier(next_type)) {
1666                 const struct btf_type *resolved_type;
1667                 u32 resolved_type_id;
1668 
1669                 resolved_type_id = next_type_id;
1670                 resolved_type = btf_type_id_resolve(btf, &resolved_type_id);
1671 
1672                 if (btf_type_is_ptr(resolved_type) &&
1673                     !env_type_is_resolve_sink(env, resolved_type) &&
1674                     !env_type_is_resolved(env, resolved_type_id))
1675                         return env_stack_push(env, resolved_type,
1676                                               resolved_type_id);
1677         }
1678 
1679         /* We must resolve to something concrete at this point, no
1680          * forward types or similar that would resolve to size of
1681          * zero is allowed.
1682          */
1683         if (!btf_type_id_size(btf, &next_type_id, NULL)) {
1684                 btf_verifier_log_type(env, v->t, "Invalid type_id");
1685                 return -EINVAL;
1686         }
1687 
1688         env_stack_pop_resolved(env, next_type_id, 0);
1689 
1690         return 0;
1691 }
1692 
1693 static int btf_ptr_resolve(struct btf_verifier_env *env,
1694                            const struct resolve_vertex *v)
1695 {
1696         const struct btf_type *next_type;
1697         const struct btf_type *t = v->t;
1698         u32 next_type_id = t->type;
1699         struct btf *btf = env->btf;
1700 
1701         next_type = btf_type_by_id(btf, next_type_id);
1702         if (!next_type || btf_type_is_resolve_source_only(next_type)) {
1703                 btf_verifier_log_type(env, v->t, "Invalid type_id");
1704                 return -EINVAL;
1705         }
1706 
1707         if (!env_type_is_resolve_sink(env, next_type) &&
1708             !env_type_is_resolved(env, next_type_id))
1709                 return env_stack_push(env, next_type, next_type_id);
1710 
1711         /* If the modifier was RESOLVED during RESOLVE_STRUCT_OR_ARRAY,
1712          * the modifier may have stopped resolving when it was resolved
1713          * to a ptr (last-resolved-ptr).
1714          *
1715          * We now need to continue from the last-resolved-ptr to
1716          * ensure the last-resolved-ptr will not referring back to
1717          * the currenct ptr (t).
1718          */
1719         if (btf_type_is_modifier(next_type)) {
1720                 const struct btf_type *resolved_type;
1721                 u32 resolved_type_id;
1722 
1723                 resolved_type_id = next_type_id;
1724                 resolved_type = btf_type_id_resolve(btf, &resolved_type_id);
1725 
1726                 if (btf_type_is_ptr(resolved_type) &&
1727                     !env_type_is_resolve_sink(env, resolved_type) &&
1728                     !env_type_is_resolved(env, resolved_type_id))
1729                         return env_stack_push(env, resolved_type,
1730                                               resolved_type_id);
1731         }
1732 
1733         if (!btf_type_id_size(btf, &next_type_id, NULL)) {
1734                 if (env_type_is_resolved(env, next_type_id))
1735                         next_type = btf_type_id_resolve(btf, &next_type_id);
1736 
1737                 if (!btf_type_is_void(next_type) &&
1738                     !btf_type_is_fwd(next_type) &&
1739                     !btf_type_is_func_proto(next_type)) {
1740                         btf_verifier_log_type(env, v->t, "Invalid type_id");
1741                         return -EINVAL;
1742                 }
1743         }
1744 
1745         env_stack_pop_resolved(env, next_type_id, 0);
1746 
1747         return 0;
1748 }
1749 
1750 static void btf_modifier_seq_show(const struct btf *btf,
1751                                   const struct btf_type *t,
1752                                   u32 type_id, void *data,
1753                                   u8 bits_offset, struct seq_file *m)
1754 {
1755         t = btf_type_id_resolve(btf, &type_id);
1756 
1757         btf_type_ops(t)->seq_show(btf, t, type_id, data, bits_offset, m);
1758 }
1759 
1760 static void btf_var_seq_show(const struct btf *btf, const struct btf_type *t,
1761                              u32 type_id, void *data, u8 bits_offset,
1762                              struct seq_file *m)
1763 {
1764         t = btf_type_id_resolve(btf, &type_id);
1765 
1766         btf_type_ops(t)->seq_show(btf, t, type_id, data, bits_offset, m);
1767 }
1768 
1769 static void btf_ptr_seq_show(const struct btf *btf, const struct btf_type *t,
1770                              u32 type_id, void *data, u8 bits_offset,
1771                              struct seq_file *m)
1772 {
1773         /* It is a hashed value */
1774         seq_printf(m, "%p", *(void **)data);
1775 }
1776 
1777 static void btf_ref_type_log(struct btf_verifier_env *env,
1778                              const struct btf_type *t)
1779 {
1780         btf_verifier_log(env, "type_id=%u", t->type);
1781 }
1782 
1783 static struct btf_kind_operations modifier_ops = {
1784         .check_meta = btf_ref_type_check_meta,
1785         .resolve = btf_modifier_resolve,
1786         .check_member = btf_modifier_check_member,
1787         .check_kflag_member = btf_modifier_check_kflag_member,
1788         .log_details = btf_ref_type_log,
1789         .seq_show = btf_modifier_seq_show,
1790 };
1791 
1792 static struct btf_kind_operations ptr_ops = {
1793         .check_meta = btf_ref_type_check_meta,
1794         .resolve = btf_ptr_resolve,
1795         .check_member = btf_ptr_check_member,
1796         .check_kflag_member = btf_generic_check_kflag_member,
1797         .log_details = btf_ref_type_log,
1798         .seq_show = btf_ptr_seq_show,
1799 };
1800 
1801 static s32 btf_fwd_check_meta(struct btf_verifier_env *env,
1802                               const struct btf_type *t,
1803                               u32 meta_left)
1804 {
1805         if (btf_type_vlen(t)) {
1806                 btf_verifier_log_type(env, t, "vlen != 0");
1807                 return -EINVAL;
1808         }
1809 
1810         if (t->type) {
1811                 btf_verifier_log_type(env, t, "type != 0");
1812                 return -EINVAL;
1813         }
1814 
1815         /* fwd type must have a valid name */
1816         if (!t->name_off ||
1817             !btf_name_valid_identifier(env->btf, t->name_off)) {
1818                 btf_verifier_log_type(env, t, "Invalid name");
1819                 return -EINVAL;
1820         }
1821 
1822         btf_verifier_log_type(env, t, NULL);
1823 
1824         return 0;
1825 }
1826 
1827 static void btf_fwd_type_log(struct btf_verifier_env *env,
1828                              const struct btf_type *t)
1829 {
1830         btf_verifier_log(env, "%s", btf_type_kflag(t) ? "union" : "struct");
1831 }
1832 
1833 static struct btf_kind_operations fwd_ops = {
1834         .check_meta = btf_fwd_check_meta,
1835         .resolve = btf_df_resolve,
1836         .check_member = btf_df_check_member,
1837         .check_kflag_member = btf_df_check_kflag_member,
1838         .log_details = btf_fwd_type_log,
1839         .seq_show = btf_df_seq_show,
1840 };
1841 
1842 static int btf_array_check_member(struct btf_verifier_env *env,
1843                                   const struct btf_type *struct_type,
1844                                   const struct btf_member *member,
1845                                   const struct btf_type *member_type)
1846 {
1847         u32 struct_bits_off = member->offset;
1848         u32 struct_size, bytes_offset;
1849         u32 array_type_id, array_size;
1850         struct btf *btf = env->btf;
1851 
1852         if (BITS_PER_BYTE_MASKED(struct_bits_off)) {
1853                 btf_verifier_log_member(env, struct_type, member,
1854                                         "Member is not byte aligned");
1855                 return -EINVAL;
1856         }
1857 
1858         array_type_id = member->type;
1859         btf_type_id_size(btf, &array_type_id, &array_size);
1860         struct_size = struct_type->size;
1861         bytes_offset = BITS_ROUNDDOWN_BYTES(struct_bits_off);
1862         if (struct_size - bytes_offset < array_size) {
1863                 btf_verifier_log_member(env, struct_type, member,
1864                                         "Member exceeds struct_size");
1865                 return -EINVAL;
1866         }
1867 
1868         return 0;
1869 }
1870 
1871 static s32 btf_array_check_meta(struct btf_verifier_env *env,
1872                                 const struct btf_type *t,
1873                                 u32 meta_left)
1874 {
1875         const struct btf_array *array = btf_type_array(t);
1876         u32 meta_needed = sizeof(*array);
1877 
1878         if (meta_left < meta_needed) {
1879                 btf_verifier_log_basic(env, t,
1880                                        "meta_left:%u meta_needed:%u",
1881                                        meta_left, meta_needed);
1882                 return -EINVAL;
1883         }
1884 
1885         /* array type should not have a name */
1886         if (t->name_off) {
1887                 btf_verifier_log_type(env, t, "Invalid name");
1888                 return -EINVAL;
1889         }
1890 
1891         if (btf_type_vlen(t)) {
1892                 btf_verifier_log_type(env, t, "vlen != 0");
1893                 return -EINVAL;
1894         }
1895 
1896         if (btf_type_kflag(t)) {
1897                 btf_verifier_log_type(env, t, "Invalid btf_info kind_flag");
1898                 return -EINVAL;
1899         }
1900 
1901         if (t->size) {
1902                 btf_verifier_log_type(env, t, "size != 0");
1903                 return -EINVAL;
1904         }
1905 
1906         /* Array elem type and index type cannot be in type void,
1907          * so !array->type and !array->index_type are not allowed.
1908          */
1909         if (!array->type || !BTF_TYPE_ID_VALID(array->type)) {
1910                 btf_verifier_log_type(env, t, "Invalid elem");
1911                 return -EINVAL;
1912         }
1913 
1914         if (!array->index_type || !BTF_TYPE_ID_VALID(array->index_type)) {
1915                 btf_verifier_log_type(env, t, "Invalid index");
1916                 return -EINVAL;
1917         }
1918 
1919         btf_verifier_log_type(env, t, NULL);
1920 
1921         return meta_needed;
1922 }
1923 
1924 static int btf_array_resolve(struct btf_verifier_env *env,
1925                              const struct resolve_vertex *v)
1926 {
1927         const struct btf_array *array = btf_type_array(v->t);
1928         const struct btf_type *elem_type, *index_type;
1929         u32 elem_type_id, index_type_id;
1930         struct btf *btf = env->btf;
1931         u32 elem_size;
1932 
1933         /* Check array->index_type */
1934         index_type_id = array->index_type;
1935         index_type = btf_type_by_id(btf, index_type_id);
1936         if (btf_type_nosize_or_null(index_type) ||
1937             btf_type_is_resolve_source_only(index_type)) {
1938                 btf_verifier_log_type(env, v->t, "Invalid index");
1939                 return -EINVAL;
1940         }
1941 
1942         if (!env_type_is_resolve_sink(env, index_type) &&
1943             !env_type_is_resolved(env, index_type_id))
1944                 return env_stack_push(env, index_type, index_type_id);
1945 
1946         index_type = btf_type_id_size(btf, &index_type_id, NULL);
1947         if (!index_type || !btf_type_is_int(index_type) ||
1948             !btf_type_int_is_regular(index_type)) {
1949                 btf_verifier_log_type(env, v->t, "Invalid index");
1950                 return -EINVAL;
1951         }
1952 
1953         /* Check array->type */
1954         elem_type_id = array->type;
1955         elem_type = btf_type_by_id(btf, elem_type_id);
1956         if (btf_type_nosize_or_null(elem_type) ||
1957             btf_type_is_resolve_source_only(elem_type)) {
1958                 btf_verifier_log_type(env, v->t,
1959                                       "Invalid elem");
1960                 return -EINVAL;
1961         }
1962 
1963         if (!env_type_is_resolve_sink(env, elem_type) &&
1964             !env_type_is_resolved(env, elem_type_id))
1965                 return env_stack_push(env, elem_type, elem_type_id);
1966 
1967         elem_type = btf_type_id_size(btf, &elem_type_id, &elem_size);
1968         if (!elem_type) {
1969                 btf_verifier_log_type(env, v->t, "Invalid elem");
1970                 return -EINVAL;
1971         }
1972 
1973         if (btf_type_is_int(elem_type) && !btf_type_int_is_regular(elem_type)) {
1974                 btf_verifier_log_type(env, v->t, "Invalid array of int");
1975                 return -EINVAL;
1976         }
1977 
1978         if (array->nelems && elem_size > U32_MAX / array->nelems) {
1979                 btf_verifier_log_type(env, v->t,
1980                                       "Array size overflows U32_MAX");
1981                 return -EINVAL;
1982         }
1983 
1984         env_stack_pop_resolved(env, elem_type_id, elem_size * array->nelems);
1985 
1986         return 0;
1987 }
1988 
1989 static void btf_array_log(struct btf_verifier_env *env,
1990                           const struct btf_type *t)
1991 {
1992         const struct btf_array *array = btf_type_array(t);
1993 
1994         btf_verifier_log(env, "type_id=%u index_type_id=%u nr_elems=%u",
1995                          array->type, array->index_type, array->nelems);
1996 }
1997 
1998 static void btf_array_seq_show(const struct btf *btf, const struct btf_type *t,
1999                                u32 type_id, void *data, u8 bits_offset,
2000                                struct seq_file *m)
2001 {
2002         const struct btf_array *array = btf_type_array(t);
2003         const struct btf_kind_operations *elem_ops;
2004         const struct btf_type *elem_type;
2005         u32 i, elem_size, elem_type_id;
2006 
2007         elem_type_id = array->type;
2008         elem_type = btf_type_id_size(btf, &elem_type_id, &elem_size);
2009         elem_ops = btf_type_ops(elem_type);
2010         seq_puts(m, "[");
2011         for (i = 0; i < array->nelems; i++) {
2012                 if (i)
2013                         seq_puts(m, ",");
2014 
2015                 elem_ops->seq_show(btf, elem_type, elem_type_id, data,
2016                                    bits_offset, m);
2017                 data += elem_size;
2018         }
2019         seq_puts(m, "]");
2020 }
2021 
2022 static struct btf_kind_operations array_ops = {
2023         .check_meta = btf_array_check_meta,
2024         .resolve = btf_array_resolve,
2025         .check_member = btf_array_check_member,
2026         .check_kflag_member = btf_generic_check_kflag_member,
2027         .log_details = btf_array_log,
2028         .seq_show = btf_array_seq_show,
2029 };
2030 
2031 static int btf_struct_check_member(struct btf_verifier_env *env,
2032                                    const struct btf_type *struct_type,
2033                                    const struct btf_member *member,
2034                                    const struct btf_type *member_type)
2035 {
2036         u32 struct_bits_off = member->offset;
2037         u32 struct_size, bytes_offset;
2038 
2039         if (BITS_PER_BYTE_MASKED(struct_bits_off)) {
2040                 btf_verifier_log_member(env, struct_type, member,
2041                                         "Member is not byte aligned");
2042                 return -EINVAL;
2043         }
2044 
2045         struct_size = struct_type->size;
2046         bytes_offset = BITS_ROUNDDOWN_BYTES(struct_bits_off);
2047         if (struct_size - bytes_offset < member_type->size) {
2048                 btf_verifier_log_member(env, struct_type, member,
2049                                         "Member exceeds struct_size");
2050                 return -EINVAL;
2051         }
2052 
2053         return 0;
2054 }
2055 
2056 static s32 btf_struct_check_meta(struct btf_verifier_env *env,
2057                                  const struct btf_type *t,
2058                                  u32 meta_left)
2059 {
2060         bool is_union = BTF_INFO_KIND(t->info) == BTF_KIND_UNION;
2061         const struct btf_member *member;
2062         u32 meta_needed, last_offset;
2063         struct btf *btf = env->btf;
2064         u32 struct_size = t->size;
2065         u32 offset;
2066         u16 i;
2067 
2068         meta_needed = btf_type_vlen(t) * sizeof(*member);
2069         if (meta_left < meta_needed) {
2070                 btf_verifier_log_basic(env, t,
2071                                        "meta_left:%u meta_needed:%u",
2072                                        meta_left, meta_needed);
2073                 return -EINVAL;
2074         }
2075 
2076         /* struct type either no name or a valid one */
2077         if (t->name_off &&
2078             !btf_name_valid_identifier(env->btf, t->name_off)) {
2079                 btf_verifier_log_type(env, t, "Invalid name");
2080                 return -EINVAL;
2081         }
2082 
2083         btf_verifier_log_type(env, t, NULL);
2084 
2085         last_offset = 0;
2086         for_each_member(i, t, member) {
2087                 if (!btf_name_offset_valid(btf, member->name_off)) {
2088                         btf_verifier_log_member(env, t, member,
2089                                                 "Invalid member name_offset:%u",
2090                                                 member->name_off);
2091                         return -EINVAL;
2092                 }
2093 
2094                 /* struct member either no name or a valid one */
2095                 if (member->name_off &&
2096                     !btf_name_valid_identifier(btf, member->name_off)) {
2097                         btf_verifier_log_member(env, t, member, "Invalid name");
2098                         return -EINVAL;
2099                 }
2100                 /* A member cannot be in type void */
2101                 if (!member->type || !BTF_TYPE_ID_VALID(member->type)) {
2102                         btf_verifier_log_member(env, t, member,
2103                                                 "Invalid type_id");
2104                         return -EINVAL;
2105                 }
2106 
2107                 offset = btf_member_bit_offset(t, member);
2108                 if (is_union && offset) {
2109                         btf_verifier_log_member(env, t, member,
2110                                                 "Invalid member bits_offset");
2111                         return -EINVAL;
2112                 }
2113 
2114                 /*
2115                  * ">" instead of ">=" because the last member could be
2116                  * "char a[0];"
2117                  */
2118                 if (last_offset > offset) {
2119                         btf_verifier_log_member(env, t, member,
2120                                                 "Invalid member bits_offset");
2121                         return -EINVAL;
2122                 }
2123 
2124                 if (BITS_ROUNDUP_BYTES(offset) > struct_size) {
2125                         btf_verifier_log_member(env, t, member,
2126                                                 "Member bits_offset exceeds its struct size");
2127                         return -EINVAL;
2128                 }
2129 
2130                 btf_verifier_log_member(env, t, member, NULL);
2131                 last_offset = offset;
2132         }
2133 
2134         return meta_needed;
2135 }
2136 
2137 static int btf_struct_resolve(struct btf_verifier_env *env,
2138                               const struct resolve_vertex *v)
2139 {
2140         const struct btf_member *member;
2141         int err;
2142         u16 i;
2143 
2144         /* Before continue resolving the next_member,
2145          * ensure the last member is indeed resolved to a
2146          * type with size info.
2147          */
2148         if (v->next_member) {
2149                 const struct btf_type *last_member_type;
2150                 const struct btf_member *last_member;
2151                 u16 last_member_type_id;
2152 
2153                 last_member = btf_type_member(v->t) + v->next_member - 1;
2154                 last_member_type_id = last_member->type;
2155                 if (WARN_ON_ONCE(!env_type_is_resolved(env,
2156                                                        last_member_type_id)))
2157                         return -EINVAL;
2158 
2159                 last_member_type = btf_type_by_id(env->btf,
2160                                                   last_member_type_id);
2161                 if (btf_type_kflag(v->t))
2162                         err = btf_type_ops(last_member_type)->check_kflag_member(env, v->t,
2163                                                                 last_member,
2164                                                                 last_member_type);
2165                 else
2166                         err = btf_type_ops(last_member_type)->check_member(env, v->t,
2167                                                                 last_member,
2168                                                                 last_member_type);
2169                 if (err)
2170                         return err;
2171         }
2172 
2173         for_each_member_from(i, v->next_member, v->t, member) {
2174                 u32 member_type_id = member->type;
2175                 const struct btf_type *member_type = btf_type_by_id(env->btf,
2176                                                                 member_type_id);
2177 
2178                 if (btf_type_nosize_or_null(member_type) ||
2179                     btf_type_is_resolve_source_only(member_type)) {
2180                         btf_verifier_log_member(env, v->t, member,
2181                                                 "Invalid member");
2182                         return -EINVAL;
2183                 }
2184 
2185                 if (!env_type_is_resolve_sink(env, member_type) &&
2186                     !env_type_is_resolved(env, member_type_id)) {
2187                         env_stack_set_next_member(env, i + 1);
2188                         return env_stack_push(env, member_type, member_type_id);
2189                 }
2190 
2191                 if (btf_type_kflag(v->t))
2192                         err = btf_type_ops(member_type)->check_kflag_member(env, v->t,
2193                                                                             member,
2194                                                                             member_type);
2195                 else
2196                         err = btf_type_ops(member_type)->check_member(env, v->t,
2197                                                                       member,
2198                                                                       member_type);
2199                 if (err)
2200                         return err;
2201         }
2202 
2203         env_stack_pop_resolved(env, 0, 0);
2204 
2205         return 0;
2206 }
2207 
2208 static void btf_struct_log(struct btf_verifier_env *env,
2209                            const struct btf_type *t)
2210 {
2211         btf_verifier_log(env, "size=%u vlen=%u", t->size, btf_type_vlen(t));
2212 }
2213 
2214 /* find 'struct bpf_spin_lock' in map value.
2215  * return >= 0 offset if found
2216  * and < 0 in case of error
2217  */
2218 int btf_find_spin_lock(const struct btf *btf, const struct btf_type *t)
2219 {
2220         const struct btf_member *member;
2221         u32 i, off = -ENOENT;
2222 
2223         if (!__btf_type_is_struct(t))
2224                 return -EINVAL;
2225 
2226         for_each_member(i, t, member) {
2227                 const struct btf_type *member_type = btf_type_by_id(btf,
2228                                                                     member->type);
2229                 if (!__btf_type_is_struct(member_type))
2230                         continue;
2231                 if (member_type->size != sizeof(struct bpf_spin_lock))
2232                         continue;
2233                 if (strcmp(__btf_name_by_offset(btf, member_type->name_off),
2234                            "bpf_spin_lock"))
2235                         continue;
2236                 if (off != -ENOENT)
2237                         /* only one 'struct bpf_spin_lock' is allowed */
2238                         return -E2BIG;
2239                 off = btf_member_bit_offset(t, member);
2240                 if (off % 8)
2241                         /* valid C code cannot generate such BTF */
2242                         return -EINVAL;
2243                 off /= 8;
2244                 if (off % __alignof__(struct bpf_spin_lock))
2245                         /* valid struct bpf_spin_lock will be 4 byte aligned */
2246                         return -EINVAL;
2247         }
2248         return off;
2249 }
2250 
2251 static void btf_struct_seq_show(const struct btf *btf, const struct btf_type *t,
2252                                 u32 type_id, void *data, u8 bits_offset,
2253                                 struct seq_file *m)
2254 {
2255         const char *seq = BTF_INFO_KIND(t->info) == BTF_KIND_UNION ? "|" : ",";
2256         const struct btf_member *member;
2257         u32 i;
2258 
2259         seq_puts(m, "{");
2260         for_each_member(i, t, member) {
2261                 const struct btf_type *member_type = btf_type_by_id(btf,
2262                                                                 member->type);
2263                 const struct btf_kind_operations *ops;
2264                 u32 member_offset, bitfield_size;
2265                 u32 bytes_offset;
2266                 u8 bits8_offset;
2267 
2268                 if (i)
2269                         seq_puts(m, seq);
2270 
2271                 member_offset = btf_member_bit_offset(t, member);
2272                 bitfield_size = btf_member_bitfield_size(t, member);
2273                 bytes_offset = BITS_ROUNDDOWN_BYTES(member_offset);
2274                 bits8_offset = BITS_PER_BYTE_MASKED(member_offset);
2275                 if (bitfield_size) {
2276                         btf_bitfield_seq_show(data + bytes_offset, bits8_offset,
2277                                               bitfield_size, m);
2278                 } else {
2279                         ops = btf_type_ops(member_type);
2280                         ops->seq_show(btf, member_type, member->type,
2281                                       data + bytes_offset, bits8_offset, m);
2282                 }
2283         }
2284         seq_puts(m, "}");
2285 }
2286 
2287 static struct btf_kind_operations struct_ops = {
2288         .check_meta = btf_struct_check_meta,
2289         .resolve = btf_struct_resolve,
2290         .check_member = btf_struct_check_member,
2291         .check_kflag_member = btf_generic_check_kflag_member,
2292         .log_details = btf_struct_log,
2293         .seq_show = btf_struct_seq_show,
2294 };
2295 
2296 static int btf_enum_check_member(struct btf_verifier_env *env,
2297                                  const struct btf_type *struct_type,
2298                                  const struct btf_member *member,
2299                                  const struct btf_type *member_type)
2300 {
2301         u32 struct_bits_off = member->offset;
2302         u32 struct_size, bytes_offset;
2303 
2304         if (BITS_PER_BYTE_MASKED(struct_bits_off)) {
2305                 btf_verifier_log_member(env, struct_type, member,
2306                                         "Member is not byte aligned");
2307                 return -EINVAL;
2308         }
2309 
2310         struct_size = struct_type->size;
2311         bytes_offset = BITS_ROUNDDOWN_BYTES(struct_bits_off);
2312         if (struct_size - bytes_offset < member_type->size) {
2313                 btf_verifier_log_member(env, struct_type, member,
2314                                         "Member exceeds struct_size");
2315                 return -EINVAL;
2316         }
2317 
2318         return 0;
2319 }
2320 
2321 static int btf_enum_check_kflag_member(struct btf_verifier_env *env,
2322                                        const struct btf_type *struct_type,
2323                                        const struct btf_member *member,
2324                                        const struct btf_type *member_type)
2325 {
2326         u32 struct_bits_off, nr_bits, bytes_end, struct_size;
2327         u32 int_bitsize = sizeof(int) * BITS_PER_BYTE;
2328 
2329         struct_bits_off = BTF_MEMBER_BIT_OFFSET(member->offset);
2330         nr_bits = BTF_MEMBER_BITFIELD_SIZE(member->offset);
2331         if (!nr_bits) {
2332                 if (BITS_PER_BYTE_MASKED(struct_bits_off)) {
2333                         btf_verifier_log_member(env, struct_type, member,
2334                                                 "Member is not byte aligned");
2335                         return -EINVAL;
2336                 }
2337 
2338                 nr_bits = int_bitsize;
2339         } else if (nr_bits > int_bitsize) {
2340                 btf_verifier_log_member(env, struct_type, member,
2341                                         "Invalid member bitfield_size");
2342                 return -EINVAL;
2343         }
2344 
2345         struct_size = struct_type->size;
2346         bytes_end = BITS_ROUNDUP_BYTES(struct_bits_off + nr_bits);
2347         if (struct_size < bytes_end) {
2348                 btf_verifier_log_member(env, struct_type, member,
2349                                         "Member exceeds struct_size");
2350                 return -EINVAL;
2351         }
2352 
2353         return 0;
2354 }
2355 
2356 static s32 btf_enum_check_meta(struct btf_verifier_env *env,
2357                                const struct btf_type *t,
2358                                u32 meta_left)
2359 {
2360         const struct btf_enum *enums = btf_type_enum(t);
2361         struct btf *btf = env->btf;
2362         u16 i, nr_enums;
2363         u32 meta_needed;
2364 
2365         nr_enums = btf_type_vlen(t);
2366         meta_needed = nr_enums * sizeof(*enums);
2367 
2368         if (meta_left < meta_needed) {
2369                 btf_verifier_log_basic(env, t,
2370                                        "meta_left:%u meta_needed:%u",
2371                                        meta_left, meta_needed);
2372                 return -EINVAL;
2373         }
2374 
2375         if (btf_type_kflag(t)) {
2376                 btf_verifier_log_type(env, t, "Invalid btf_info kind_flag");
2377                 return -EINVAL;
2378         }
2379 
2380         if (t->size > 8 || !is_power_of_2(t->size)) {
2381                 btf_verifier_log_type(env, t, "Unexpected size");
2382                 return -EINVAL;
2383         }
2384 
2385         /* enum type either no name or a valid one */
2386         if (t->name_off &&
2387             !btf_name_valid_identifier(env->btf, t->name_off)) {
2388                 btf_verifier_log_type(env, t, "Invalid name");
2389                 return -EINVAL;
2390         }
2391 
2392         btf_verifier_log_type(env, t, NULL);
2393 
2394         for (i = 0; i < nr_enums; i++) {
2395                 if (!btf_name_offset_valid(btf, enums[i].name_off)) {
2396                         btf_verifier_log(env, "\tInvalid name_offset:%u",
2397                                          enums[i].name_off);
2398                         return -EINVAL;
2399                 }
2400 
2401                 /* enum member must have a valid name */
2402                 if (!enums[i].name_off ||
2403                     !btf_name_valid_identifier(btf, enums[i].name_off)) {
2404                         btf_verifier_log_type(env, t, "Invalid name");
2405                         return -EINVAL;
2406                 }
2407 
2408 
2409                 btf_verifier_log(env, "\t%s val=%d\n",
2410                                  __btf_name_by_offset(btf, enums[i].name_off),
2411                                  enums[i].val);
2412         }
2413 
2414         return meta_needed;
2415 }
2416 
2417 static void btf_enum_log(struct btf_verifier_env *env,
2418                          const struct btf_type *t)
2419 {
2420         btf_verifier_log(env, "size=%u vlen=%u", t->size, btf_type_vlen(t));
2421 }
2422 
2423 static void btf_enum_seq_show(const struct btf *btf, const struct btf_type *t,
2424                               u32 type_id, void *data, u8 bits_offset,
2425                               struct seq_file *m)
2426 {
2427         const struct btf_enum *enums = btf_type_enum(t);
2428         u32 i, nr_enums = btf_type_vlen(t);
2429         int v = *(int *)data;
2430 
2431         for (i = 0; i < nr_enums; i++) {
2432                 if (v == enums[i].val) {
2433                         seq_printf(m, "%s",
2434                                    __btf_name_by_offset(btf,
2435                                                         enums[i].name_off));
2436                         return;
2437                 }
2438         }
2439 
2440         seq_printf(m, "%d", v);
2441 }
2442 
2443 static struct btf_kind_operations enum_ops = {
2444         .check_meta = btf_enum_check_meta,
2445         .resolve = btf_df_resolve,
2446         .check_member = btf_enum_check_member,
2447         .check_kflag_member = btf_enum_check_kflag_member,
2448         .log_details = btf_enum_log,
2449         .seq_show = btf_enum_seq_show,
2450 };
2451 
2452 static s32 btf_func_proto_check_meta(struct btf_verifier_env *env,
2453                                      const struct btf_type *t,
2454                                      u32 meta_left)
2455 {
2456         u32 meta_needed = btf_type_vlen(t) * sizeof(struct btf_param);
2457 
2458         if (meta_left < meta_needed) {
2459                 btf_verifier_log_basic(env, t,
2460                                        "meta_left:%u meta_needed:%u",
2461                                        meta_left, meta_needed);
2462                 return -EINVAL;
2463         }
2464 
2465         if (t->name_off) {
2466                 btf_verifier_log_type(env, t, "Invalid name");
2467                 return -EINVAL;
2468         }
2469 
2470         if (btf_type_kflag(t)) {
2471                 btf_verifier_log_type(env, t, "Invalid btf_info kind_flag");
2472                 return -EINVAL;
2473         }
2474 
2475         btf_verifier_log_type(env, t, NULL);
2476 
2477         return meta_needed;
2478 }
2479 
2480 static void btf_func_proto_log(struct btf_verifier_env *env,
2481                                const struct btf_type *t)
2482 {
2483         const struct btf_param *args = (const struct btf_param *)(t + 1);
2484         u16 nr_args = btf_type_vlen(t), i;
2485 
2486         btf_verifier_log(env, "return=%u args=(", t->type);
2487         if (!nr_args) {
2488                 btf_verifier_log(env, "void");
2489                 goto done;
2490         }
2491 
2492         if (nr_args == 1 && !args[0].type) {
2493                 /* Only one vararg */
2494                 btf_verifier_log(env, "vararg");
2495                 goto done;
2496         }
2497 
2498         btf_verifier_log(env, "%u %s", args[0].type,
2499                          __btf_name_by_offset(env->btf,
2500                                               args[0].name_off));
2501         for (i = 1; i < nr_args - 1; i++)
2502                 btf_verifier_log(env, ", %u %s", args[i].type,
2503                                  __btf_name_by_offset(env->btf,
2504                                                       args[i].name_off));
2505 
2506         if (nr_args > 1) {
2507                 const struct btf_param *last_arg = &args[nr_args - 1];
2508 
2509                 if (last_arg->type)
2510                         btf_verifier_log(env, ", %u %s", last_arg->type,
2511                                          __btf_name_by_offset(env->btf,
2512                                                               last_arg->name_off));
2513                 else
2514                         btf_verifier_log(env, ", vararg");
2515         }
2516 
2517 done:
2518         btf_verifier_log(env, ")");
2519 }
2520 
2521 static struct btf_kind_operations func_proto_ops = {
2522         .check_meta = btf_func_proto_check_meta,
2523         .resolve = btf_df_resolve,
2524         /*
2525          * BTF_KIND_FUNC_PROTO cannot be directly referred by
2526          * a struct's member.
2527          *
2528          * It should be a funciton pointer instead.
2529          * (i.e. struct's member -> BTF_KIND_PTR -> BTF_KIND_FUNC_PROTO)
2530          *
2531          * Hence, there is no btf_func_check_member().
2532          */
2533         .check_member = btf_df_check_member,
2534         .check_kflag_member = btf_df_check_kflag_member,
2535         .log_details = btf_func_proto_log,
2536         .seq_show = btf_df_seq_show,
2537 };
2538 
2539 static s32 btf_func_check_meta(struct btf_verifier_env *env,
2540                                const struct btf_type *t,
2541                                u32 meta_left)
2542 {
2543         if (!t->name_off ||
2544             !btf_name_valid_identifier(env->btf, t->name_off)) {
2545                 btf_verifier_log_type(env, t, "Invalid name");
2546                 return -EINVAL;
2547         }
2548 
2549         if (btf_type_vlen(t)) {
2550                 btf_verifier_log_type(env, t, "vlen != 0");
2551                 return -EINVAL;
2552         }
2553 
2554         if (btf_type_kflag(t)) {
2555                 btf_verifier_log_type(env, t, "Invalid btf_info kind_flag");
2556                 return -EINVAL;
2557         }
2558 
2559         btf_verifier_log_type(env, t, NULL);
2560 
2561         return 0;
2562 }
2563 
2564 static struct btf_kind_operations func_ops = {
2565         .check_meta = btf_func_check_meta,
2566         .resolve = btf_df_resolve,
2567         .check_member = btf_df_check_member,
2568         .check_kflag_member = btf_df_check_kflag_member,
2569         .log_details = btf_ref_type_log,
2570         .seq_show = btf_df_seq_show,
2571 };
2572 
2573 static s32 btf_var_check_meta(struct btf_verifier_env *env,
2574                               const struct btf_type *t,
2575                               u32 meta_left)
2576 {
2577         const struct btf_var *var;
2578         u32 meta_needed = sizeof(*var);
2579 
2580         if (meta_left < meta_needed) {
2581                 btf_verifier_log_basic(env, t,
2582                                        "meta_left:%u meta_needed:%u",
2583                                        meta_left, meta_needed);
2584                 return -EINVAL;
2585         }
2586 
2587         if (btf_type_vlen(t)) {
2588                 btf_verifier_log_type(env, t, "vlen != 0");
2589                 return -EINVAL;
2590         }
2591 
2592         if (btf_type_kflag(t)) {
2593                 btf_verifier_log_type(env, t, "Invalid btf_info kind_flag");
2594                 return -EINVAL;
2595         }
2596 
2597         if (!t->name_off ||
2598             !__btf_name_valid(env->btf, t->name_off, true)) {
2599                 btf_verifier_log_type(env, t, "Invalid name");
2600                 return -EINVAL;
2601         }
2602 
2603         /* A var cannot be in type void */
2604         if (!t->type || !BTF_TYPE_ID_VALID(t->type)) {
2605                 btf_verifier_log_type(env, t, "Invalid type_id");
2606                 return -EINVAL;
2607         }
2608 
2609         var = btf_type_var(t);
2610         if (var->linkage != BTF_VAR_STATIC &&
2611             var->linkage != BTF_VAR_GLOBAL_ALLOCATED) {
2612                 btf_verifier_log_type(env, t, "Linkage not supported");
2613                 return -EINVAL;
2614         }
2615 
2616         btf_verifier_log_type(env, t, NULL);
2617 
2618         return meta_needed;
2619 }
2620 
2621 static void btf_var_log(struct btf_verifier_env *env, const struct btf_type *t)
2622 {
2623         const struct btf_var *var = btf_type_var(t);
2624 
2625         btf_verifier_log(env, "type_id=%u linkage=%u", t->type, var->linkage);
2626 }
2627 
2628 static const struct btf_kind_operations var_ops = {
2629         .check_meta             = btf_var_check_meta,
2630         .resolve                = btf_var_resolve,
2631         .check_member           = btf_df_check_member,
2632         .check_kflag_member     = btf_df_check_kflag_member,
2633         .log_details            = btf_var_log,
2634         .seq_show               = btf_var_seq_show,
2635 };
2636 
2637 static s32 btf_datasec_check_meta(struct btf_verifier_env *env,
2638                                   const struct btf_type *t,
2639                                   u32 meta_left)
2640 {
2641         const struct btf_var_secinfo *vsi;
2642         u64 last_vsi_end_off = 0, sum = 0;
2643         u32 i, meta_needed;
2644 
2645         meta_needed = btf_type_vlen(t) * sizeof(*vsi);
2646         if (meta_left < meta_needed) {
2647                 btf_verifier_log_basic(env, t,
2648                                        "meta_left:%u meta_needed:%u",
2649                                        meta_left, meta_needed);
2650                 return -EINVAL;
2651         }
2652 
2653         if (!btf_type_vlen(t)) {
2654                 btf_verifier_log_type(env, t, "vlen == 0");
2655                 return -EINVAL;
2656         }
2657 
2658         if (!t->size) {
2659                 btf_verifier_log_type(env, t, "size == 0");
2660                 return -EINVAL;
2661         }
2662 
2663         if (btf_type_kflag(t)) {
2664                 btf_verifier_log_type(env, t, "Invalid btf_info kind_flag");
2665                 return -EINVAL;
2666         }
2667 
2668         if (!t->name_off ||
2669             !btf_name_valid_section(env->btf, t->name_off)) {
2670                 btf_verifier_log_type(env, t, "Invalid name");
2671                 return -EINVAL;
2672         }
2673 
2674         btf_verifier_log_type(env, t, NULL);
2675 
2676         for_each_vsi(i, t, vsi) {
2677                 /* A var cannot be in type void */
2678                 if (!vsi->type || !BTF_TYPE_ID_VALID(vsi->type)) {
2679                         btf_verifier_log_vsi(env, t, vsi,
2680                                              "Invalid type_id");
2681                         return -EINVAL;
2682                 }
2683 
2684                 if (vsi->offset < last_vsi_end_off || vsi->offset >= t->size) {
2685                         btf_verifier_log_vsi(env, t, vsi,
2686                                              "Invalid offset");
2687                         return -EINVAL;
2688                 }
2689 
2690                 if (!vsi->size || vsi->size > t->size) {
2691                         btf_verifier_log_vsi(env, t, vsi,
2692                                              "Invalid size");
2693                         return -EINVAL;
2694                 }
2695 
2696                 last_vsi_end_off = vsi->offset + vsi->size;
2697                 if (last_vsi_end_off > t->size) {
2698                         btf_verifier_log_vsi(env, t, vsi,
2699                                              "Invalid offset+size");
2700                         return -EINVAL;
2701                 }
2702 
2703                 btf_verifier_log_vsi(env, t, vsi, NULL);
2704                 sum += vsi->size;
2705         }
2706 
2707         if (t->size < sum) {
2708                 btf_verifier_log_type(env, t, "Invalid btf_info size");
2709                 return -EINVAL;
2710         }
2711 
2712         return meta_needed;
2713 }
2714 
2715 static int btf_datasec_resolve(struct btf_verifier_env *env,
2716                                const struct resolve_vertex *v)
2717 {
2718         const struct btf_var_secinfo *vsi;
2719         struct btf *btf = env->btf;
2720         u16 i;
2721 
2722         for_each_vsi_from(i, v->next_member, v->t, vsi) {
2723                 u32 var_type_id = vsi->type, type_id, type_size = 0;
2724                 const struct btf_type *var_type = btf_type_by_id(env->btf,
2725                                                                  var_type_id);
2726                 if (!var_type || !btf_type_is_var(var_type)) {
2727                         btf_verifier_log_vsi(env, v->t, vsi,
2728                                              "Not a VAR kind member");
2729                         return -EINVAL;
2730                 }
2731 
2732                 if (!env_type_is_resolve_sink(env, var_type) &&
2733                     !env_type_is_resolved(env, var_type_id)) {
2734                         env_stack_set_next_member(env, i + 1);
2735                         return env_stack_push(env, var_type, var_type_id);
2736                 }
2737 
2738                 type_id = var_type->type;
2739                 if (!btf_type_id_size(btf, &type_id, &type_size)) {
2740                         btf_verifier_log_vsi(env, v->t, vsi, "Invalid type");
2741                         return -EINVAL;
2742                 }
2743 
2744                 if (vsi->size < type_size) {
2745                         btf_verifier_log_vsi(env, v->t, vsi, "Invalid size");
2746                         return -EINVAL;
2747                 }
2748         }
2749 
2750         env_stack_pop_resolved(env, 0, 0);
2751         return 0;
2752 }
2753 
2754 static void btf_datasec_log(struct btf_verifier_env *env,
2755                             const struct btf_type *t)
2756 {
2757         btf_verifier_log(env, "size=%u vlen=%u", t->size, btf_type_vlen(t));
2758 }
2759 
2760 static void btf_datasec_seq_show(const struct btf *btf,
2761                                  const struct btf_type *t, u32 type_id,
2762                                  void *data, u8 bits_offset,
2763                                  struct seq_file *m)
2764 {
2765         const struct btf_var_secinfo *vsi;
2766         const struct btf_type *var;
2767         u32 i;
2768 
2769         seq_printf(m, "section (\"%s\") = {", __btf_name_by_offset(btf, t->name_off));
2770         for_each_vsi(i, t, vsi) {
2771                 var = btf_type_by_id(btf, vsi->type);
2772                 if (i)
2773                         seq_puts(m, ",");
2774                 btf_type_ops(var)->seq_show(btf, var, vsi->type,
2775                                             data + vsi->offset, bits_offset, m);
2776         }
2777         seq_puts(m, "}");
2778 }
2779 
2780 static const struct btf_kind_operations datasec_ops = {
2781         .check_meta             = btf_datasec_check_meta,
2782         .resolve                = btf_datasec_resolve,
2783         .check_member           = btf_df_check_member,
2784         .check_kflag_member     = btf_df_check_kflag_member,
2785         .log_details            = btf_datasec_log,
2786         .seq_show               = btf_datasec_seq_show,
2787 };
2788 
2789 static int btf_func_proto_check(struct btf_verifier_env *env,
2790                                 const struct btf_type *t)
2791 {
2792         const struct btf_type *ret_type;
2793         const struct btf_param *args;
2794         const struct btf *btf;
2795         u16 nr_args, i;
2796         int err;
2797 
2798         btf = env->btf;
2799         args = (const struct btf_param *)(t + 1);
2800         nr_args = btf_type_vlen(t);
2801 
2802         /* Check func return type which could be "void" (t->type == 0) */
2803         if (t->type) {
2804                 u32 ret_type_id = t->type;
2805 
2806                 ret_type = btf_type_by_id(btf, ret_type_id);
2807                 if (!ret_type) {
2808                         btf_verifier_log_type(env, t, "Invalid return type");
2809                         return -EINVAL;
2810                 }
2811 
2812                 if (btf_type_needs_resolve(ret_type) &&
2813                     !env_type_is_resolved(env, ret_type_id)) {
2814                         err = btf_resolve(env, ret_type, ret_type_id);
2815                         if (err)
2816                                 return err;
2817                 }
2818 
2819                 /* Ensure the return type is a type that has a size */
2820                 if (!btf_type_id_size(btf, &ret_type_id, NULL)) {
2821                         btf_verifier_log_type(env, t, "Invalid return type");
2822                         return -EINVAL;
2823                 }
2824         }
2825 
2826         if (!nr_args)
2827                 return 0;
2828 
2829         /* Last func arg type_id could be 0 if it is a vararg */
2830         if (!args[nr_args - 1].type) {
2831                 if (args[nr_args - 1].name_off) {
2832                         btf_verifier_log_type(env, t, "Invalid arg#%u",
2833                                               nr_args);
2834                         return -EINVAL;
2835                 }
2836                 nr_args--;
2837         }
2838 
2839         err = 0;
2840         for (i = 0; i < nr_args; i++) {
2841                 const struct btf_type *arg_type;
2842                 u32 arg_type_id;
2843 
2844                 arg_type_id = args[i].type;
2845                 arg_type = btf_type_by_id(btf, arg_type_id);
2846                 if (!arg_type) {
2847                         btf_verifier_log_type(env, t, "Invalid arg#%u", i + 1);
2848                         err = -EINVAL;
2849                         break;
2850                 }
2851 
2852                 if (args[i].name_off &&
2853                     (!btf_name_offset_valid(btf, args[i].name_off) ||
2854                      !btf_name_valid_identifier(btf, args[i].name_off))) {
2855                         btf_verifier_log_type(env, t,
2856                                               "Invalid arg#%u", i + 1);
2857                         err = -EINVAL;
2858                         break;
2859                 }
2860 
2861                 if (btf_type_needs_resolve(arg_type) &&
2862                     !env_type_is_resolved(env, arg_type_id)) {
2863                         err = btf_resolve(env, arg_type, arg_type_id);
2864                         if (err)
2865                                 break;
2866                 }
2867 
2868                 if (!btf_type_id_size(btf, &arg_type_id, NULL)) {
2869                         btf_verifier_log_type(env, t, "Invalid arg#%u", i + 1);
2870                         err = -EINVAL;
2871                         break;
2872                 }
2873         }
2874 
2875         return err;
2876 }
2877 
2878 static int btf_func_check(struct btf_verifier_env *env,
2879                           const struct btf_type *t)
2880 {
2881         const struct btf_type *proto_type;
2882         const struct btf_param *args;
2883         const struct btf *btf;
2884         u16 nr_args, i;
2885 
2886         btf = env->btf;
2887         proto_type = btf_type_by_id(btf, t->type);
2888 
2889         if (!proto_type || !btf_type_is_func_proto(proto_type)) {
2890                 btf_verifier_log_type(env, t, "Invalid type_id");
2891                 return -EINVAL;
2892         }
2893 
2894         args = (const struct btf_param *)(proto_type + 1);
2895         nr_args = btf_type_vlen(proto_type);
2896         for (i = 0; i < nr_args; i++) {
2897                 if (!args[i].name_off && args[i].type) {
2898                         btf_verifier_log_type(env, t, "Invalid arg#%u", i + 1);
2899                         return -EINVAL;
2900                 }
2901         }
2902 
2903         return 0;
2904 }
2905 
2906 static const struct btf_kind_operations * const kind_ops[NR_BTF_KINDS] = {
2907         [BTF_KIND_INT] = &int_ops,
2908         [BTF_KIND_PTR] = &ptr_ops,
2909         [BTF_KIND_ARRAY] = &array_ops,
2910         [BTF_KIND_STRUCT] = &struct_ops,
2911         [BTF_KIND_UNION] = &struct_ops,
2912         [BTF_KIND_ENUM] = &enum_ops,
2913         [BTF_KIND_FWD] = &fwd_ops,
2914         [BTF_KIND_TYPEDEF] = &modifier_ops,
2915         [BTF_KIND_VOLATILE] = &modifier_ops,
2916         [BTF_KIND_CONST] = &modifier_ops,
2917         [BTF_KIND_RESTRICT] = &modifier_ops,
2918         [BTF_KIND_FUNC] = &func_ops,
2919         [BTF_KIND_FUNC_PROTO] = &func_proto_ops,
2920         [BTF_KIND_VAR] = &var_ops,
2921         [BTF_KIND_DATASEC] = &datasec_ops,
2922 };
2923 
2924 static s32 btf_check_meta(struct btf_verifier_env *env,
2925                           const struct btf_type *t,
2926                           u32 meta_left)
2927 {
2928         u32 saved_meta_left = meta_left;
2929         s32 var_meta_size;
2930 
2931         if (meta_left < sizeof(*t)) {
2932                 btf_verifier_log(env, "[%u] meta_left:%u meta_needed:%zu",
2933                                  env->log_type_id, meta_left, sizeof(*t));
2934                 return -EINVAL;
2935         }
2936         meta_left -= sizeof(*t);
2937 
2938         if (t->info & ~BTF_INFO_MASK) {
2939                 btf_verifier_log(env, "[%u] Invalid btf_info:%x",
2940                                  env->log_type_id, t->info);
2941                 return -EINVAL;
2942         }
2943 
2944         if (BTF_INFO_KIND(t->info) > BTF_KIND_MAX ||
2945             BTF_INFO_KIND(t->info) == BTF_KIND_UNKN) {
2946                 btf_verifier_log(env, "[%u] Invalid kind:%u",
2947                                  env->log_type_id, BTF_INFO_KIND(t->info));
2948                 return -EINVAL;
2949         }
2950 
2951         if (!btf_name_offset_valid(env->btf, t->name_off)) {
2952                 btf_verifier_log(env, "[%u] Invalid name_offset:%u",
2953                                  env->log_type_id, t->name_off);
2954                 return -EINVAL;
2955         }
2956 
2957         var_meta_size = btf_type_ops(t)->check_meta(env, t, meta_left);
2958         if (var_meta_size < 0)
2959                 return var_meta_size;
2960 
2961         meta_left -= var_meta_size;
2962 
2963         return saved_meta_left - meta_left;
2964 }
2965 
2966 static int btf_check_all_metas(struct btf_verifier_env *env)
2967 {
2968         struct btf *btf = env->btf;
2969         struct btf_header *hdr;
2970         void *cur, *end;
2971 
2972         hdr = &btf->hdr;
2973         cur = btf->nohdr_data + hdr->type_off;
2974         end = cur + hdr->type_len;
2975 
2976         env->log_type_id = 1;
2977         while (cur < end) {
2978                 struct btf_type *t = cur;
2979                 s32 meta_size;
2980 
2981                 meta_size = btf_check_meta(env, t, end - cur);
2982                 if (meta_size < 0)
2983                         return meta_size;
2984 
2985                 btf_add_type(env, t);
2986                 cur += meta_size;
2987                 env->log_type_id++;
2988         }
2989 
2990         return 0;
2991 }
2992 
2993 static bool btf_resolve_valid(struct btf_verifier_env *env,
2994                               const struct btf_type *t,
2995                               u32 type_id)
2996 {
2997         struct btf *btf = env->btf;
2998 
2999         if (!env_type_is_resolved(env, type_id))
3000                 return false;
3001 
3002         if (btf_type_is_struct(t) || btf_type_is_datasec(t))
3003                 return !btf->resolved_ids[type_id] &&
3004                        !btf->resolved_sizes[type_id];
3005 
3006         if (btf_type_is_modifier(t) || btf_type_is_ptr(t) ||
3007             btf_type_is_var(t)) {
3008                 t = btf_type_id_resolve(btf, &type_id);
3009                 return t &&
3010                        !btf_type_is_modifier(t) &&
3011                        !btf_type_is_var(t) &&
3012                        !btf_type_is_datasec(t);
3013         }
3014 
3015         if (btf_type_is_array(t)) {
3016                 const struct btf_array *array = btf_type_array(t);
3017                 const struct btf_type *elem_type;
3018                 u32 elem_type_id = array->type;
3019                 u32 elem_size;
3020 
3021                 elem_type = btf_type_id_size(btf, &elem_type_id, &elem_size);
3022                 return elem_type && !btf_type_is_modifier(elem_type) &&
3023                         (array->nelems * elem_size ==
3024                          btf->resolved_sizes[type_id]);
3025         }
3026 
3027         return false;
3028 }
3029 
3030 static int btf_resolve(struct btf_verifier_env *env,
3031                        const struct btf_type *t, u32 type_id)
3032 {
3033         u32 save_log_type_id = env->log_type_id;
3034         const struct resolve_vertex *v;
3035         int err = 0;
3036 
3037         env->resolve_mode = RESOLVE_TBD;
3038         env_stack_push(env, t, type_id);
3039         while (!err && (v = env_stack_peak(env))) {
3040                 env->log_type_id = v->type_id;
3041                 err = btf_type_ops(v->t)->resolve(env, v);
3042         }
3043 
3044         env->log_type_id = type_id;
3045         if (err == -E2BIG) {
3046                 btf_verifier_log_type(env, t,
3047                                       "Exceeded max resolving depth:%u",
3048                                       MAX_RESOLVE_DEPTH);
3049         } else if (err == -EEXIST) {
3050                 btf_verifier_log_type(env, t, "Loop detected");
3051         }
3052 
3053         /* Final sanity check */
3054         if (!err && !btf_resolve_valid(env, t, type_id)) {
3055                 btf_verifier_log_type(env, t, "Invalid resolve state");
3056                 err = -EINVAL;
3057         }
3058 
3059         env->log_type_id = save_log_type_id;
3060         return err;
3061 }
3062 
3063 static int btf_check_all_types(struct btf_verifier_env *env)
3064 {
3065         struct btf *btf = env->btf;
3066         u32 type_id;
3067         int err;
3068 
3069         err = env_resolve_init(env);
3070         if (err)
3071                 return err;
3072 
3073         env->phase++;
3074         for (type_id = 1; type_id <= btf->nr_types; type_id++) {
3075                 const struct btf_type *t = btf_type_by_id(btf, type_id);
3076 
3077                 env->log_type_id = type_id;
3078                 if (btf_type_needs_resolve(t) &&
3079                     !env_type_is_resolved(env, type_id)) {
3080                         err = btf_resolve(env, t, type_id);
3081                         if (err)
3082                                 return err;
3083                 }
3084 
3085                 if (btf_type_is_func_proto(t)) {
3086                         err = btf_func_proto_check(env, t);
3087                         if (err)
3088                                 return err;
3089                 }
3090 
3091                 if (btf_type_is_func(t)) {
3092                         err = btf_func_check(env, t);
3093                         if (err)
3094                                 return err;
3095                 }
3096         }
3097 
3098         return 0;
3099 }
3100 
3101 static int btf_parse_type_sec(struct btf_verifier_env *env)
3102 {
3103         const struct btf_header *hdr = &env->btf->hdr;
3104         int err;
3105 
3106         /* Type section must align to 4 bytes */
3107         if (hdr->type_off & (sizeof(u32) - 1)) {
3108                 btf_verifier_log(env, "Unaligned type_off");
3109                 return -EINVAL;
3110         }
3111 
3112         if (!hdr->type_len) {
3113                 btf_verifier_log(env, "No type found");
3114                 return -EINVAL;
3115         }
3116 
3117         err = btf_check_all_metas(env);
3118         if (err)
3119                 return err;
3120 
3121         return btf_check_all_types(env);
3122 }
3123 
3124 static int btf_parse_str_sec(struct btf_verifier_env *env)
3125 {
3126         const struct btf_header *hdr;
3127         struct btf *btf = env->btf;
3128         const char *start, *end;
3129 
3130         hdr = &btf->hdr;
3131         start = btf->nohdr_data + hdr->str_off;
3132         end = start + hdr->str_len;
3133 
3134         if (end != btf->data + btf->data_size) {
3135                 btf_verifier_log(env, "String section is not at the end");
3136                 return -EINVAL;
3137         }
3138 
3139         if (!hdr->str_len || hdr->str_len - 1 > BTF_MAX_NAME_OFFSET ||
3140             start[0] || end[-1]) {
3141                 btf_verifier_log(env, "Invalid string section");
3142                 return -EINVAL;
3143         }
3144 
3145         btf->strings = start;
3146 
3147         return 0;
3148 }
3149 
3150 static const size_t btf_sec_info_offset[] = {
3151         offsetof(struct btf_header, type_off),
3152         offsetof(struct btf_header, str_off),
3153 };
3154 
3155 static int btf_sec_info_cmp(const void *a, const void *b)
3156 {
3157         const struct btf_sec_info *x = a;
3158         const struct btf_sec_info *y = b;
3159 
3160         return (int)(x->off - y->off) ? : (int)(x->len - y->len);
3161 }
3162 
3163 static int btf_check_sec_info(struct btf_verifier_env *env,
3164                               u32 btf_data_size)
3165 {
3166         struct btf_sec_info secs[ARRAY_SIZE(btf_sec_info_offset)];
3167         u32 total, expected_total, i;
3168         const struct btf_header *hdr;
3169         const struct btf *btf;
3170 
3171         btf = env->btf;
3172         hdr = &btf->hdr;
3173 
3174         /* Populate the secs from hdr */
3175         for (i = 0; i < ARRAY_SIZE(btf_sec_info_offset); i++)
3176                 secs[i] = *(struct btf_sec_info *)((void *)hdr +
3177                                                    btf_sec_info_offset[i]);
3178 
3179         sort(secs, ARRAY_SIZE(btf_sec_info_offset),
3180              sizeof(struct btf_sec_info), btf_sec_info_cmp, NULL);
3181 
3182         /* Check for gaps and overlap among sections */
3183         total = 0;
3184         expected_total = btf_data_size - hdr->hdr_len;
3185         for (i = 0; i < ARRAY_SIZE(btf_sec_info_offset); i++) {
3186                 if (expected_total < secs[i].off) {
3187                         btf_verifier_log(env, "Invalid section offset");
3188                         return -EINVAL;
3189                 }
3190                 if (total < secs[i].off) {
3191                         /* gap */
3192                         btf_verifier_log(env, "Unsupported section found");
3193                         return -EINVAL;
3194                 }
3195                 if (total > secs[i].off) {
3196                         btf_verifier_log(env, "Section overlap found");
3197                         return -EINVAL;
3198                 }
3199                 if (expected_total - total < secs[i].len) {
3200                         btf_verifier_log(env,
3201                                          "Total section length too long");
3202                         return -EINVAL;
3203                 }
3204                 total += secs[i].len;
3205         }
3206 
3207         /* There is data other than hdr and known sections */
3208         if (expected_total != total) {
3209                 btf_verifier_log(env, "Unsupported section found");
3210                 return -EINVAL;
3211         }
3212 
3213         return 0;
3214 }
3215 
3216 static int btf_parse_hdr(struct btf_verifier_env *env)
3217 {
3218         u32 hdr_len, hdr_copy, btf_data_size;
3219         const struct btf_header *hdr;
3220         struct btf *btf;
3221         int err;
3222 
3223         btf = env->btf;
3224         btf_data_size = btf->data_size;
3225 
3226         if (btf_data_size <
3227             offsetof(struct btf_header, hdr_len) + sizeof(hdr->hdr_len)) {
3228                 btf_verifier_log(env, "hdr_len not found");
3229                 return -EINVAL;
3230         }
3231 
3232         hdr = btf->data;
3233         hdr_len = hdr->hdr_len;
3234         if (btf_data_size < hdr_len) {
3235                 btf_verifier_log(env, "btf_header not found");
3236                 return -EINVAL;
3237         }
3238 
3239         /* Ensure the unsupported header fields are zero */
3240         if (hdr_len > sizeof(btf->hdr)) {
3241                 u8 *expected_zero = btf->data + sizeof(btf->hdr);
3242                 u8 *end = btf->data + hdr_len;
3243 
3244                 for (; expected_zero < end; expected_zero++) {
3245                         if (*expected_zero) {
3246                                 btf_verifier_log(env, "Unsupported btf_header");
3247                                 return -E2BIG;
3248                         }
3249                 }
3250         }
3251 
3252         hdr_copy = min_t(u32, hdr_len, sizeof(btf->hdr));
3253         memcpy(&btf->hdr, btf->data, hdr_copy);
3254 
3255         hdr = &btf->hdr;
3256 
3257         btf_verifier_log_hdr(env, btf_data_size);
3258 
3259         if (hdr->magic != BTF_MAGIC) {
3260                 btf_verifier_log(env, "Invalid magic");
3261                 return -EINVAL;
3262         }
3263 
3264         if (hdr->version != BTF_VERSION) {
3265                 btf_verifier_log(env, "Unsupported version");
3266                 return -ENOTSUPP;
3267         }
3268 
3269         if (hdr->flags) {
3270                 btf_verifier_log(env, "Unsupported flags");
3271                 return -ENOTSUPP;
3272         }
3273 
3274         if (btf_data_size == hdr->hdr_len) {
3275                 btf_verifier_log(env, "No data");
3276                 return -EINVAL;
3277         }
3278 
3279         err = btf_check_sec_info(env, btf_data_size);
3280         if (err)
3281                 return err;
3282 
3283         return 0;
3284 }
3285 
3286 static struct btf *btf_parse(void __user *btf_data, u32 btf_data_size,
3287                              u32 log_level, char __user *log_ubuf, u32 log_size)
3288 {
3289         struct btf_verifier_env *env = NULL;
3290         struct bpf_verifier_log *log;
3291         struct btf *btf = NULL;
3292         u8 *data;
3293         int err;
3294 
3295         if (btf_data_size > BTF_MAX_SIZE)
3296                 return ERR_PTR(-E2BIG);
3297 
3298         env = kzalloc(sizeof(*env), GFP_KERNEL | __GFP_NOWARN);
3299         if (!env)
3300                 return ERR_PTR(-ENOMEM);
3301 
3302         log = &env->log;
3303         if (log_level || log_ubuf || log_size) {
3304                 /* user requested verbose verifier output
3305                  * and supplied buffer to store the verification trace
3306                  */
3307                 log->level = log_level;
3308                 log->ubuf = log_ubuf;
3309                 log->len_total = log_size;
3310 
3311                 /* log attributes have to be sane */
3312                 if (log->len_total < 128 || log->len_total > UINT_MAX >> 8 ||
3313                     !log->level || !log->ubuf) {
3314                         err = -EINVAL;
3315                         goto errout;
3316                 }
3317         }
3318 
3319         btf = kzalloc(sizeof(*btf), GFP_KERNEL | __GFP_NOWARN);
3320         if (!btf) {
3321                 err = -ENOMEM;
3322                 goto errout;
3323         }
3324         env->btf = btf;
3325 
3326         data = kvmalloc(btf_data_size, GFP_KERNEL | __GFP_NOWARN);
3327         if (!data) {
3328                 err = -ENOMEM;
3329                 goto errout;
3330         }
3331 
3332         btf->data = data;
3333         btf->data_size = btf_data_size;
3334 
3335         if (copy_from_user(data, btf_data, btf_data_size)) {
3336                 err = -EFAULT;
3337                 goto errout;
3338         }
3339 
3340         err = btf_parse_hdr(env);
3341         if (err)
3342                 goto errout;
3343 
3344         btf->nohdr_data = btf->data + btf->hdr.hdr_len;
3345 
3346         err = btf_parse_str_sec(env);
3347         if (err)
3348                 goto errout;
3349 
3350         err = btf_parse_type_sec(env);
3351         if (err)
3352                 goto errout;
3353 
3354         if (log->level && bpf_verifier_log_full(log)) {
3355                 err = -ENOSPC;
3356                 goto errout;
3357         }
3358 
3359         btf_verifier_env_free(env);
3360         refcount_set(&btf->refcnt, 1);
3361         return btf;
3362 
3363 errout:
3364         btf_verifier_env_free(env);
3365         if (btf)
3366                 btf_free(btf);
3367         return ERR_PTR(err);
3368 }
3369 
3370 void btf_type_seq_show(const struct btf *btf, u32 type_id, void *obj,
3371                        struct seq_file *m)
3372 {
3373         const struct btf_type *t = btf_type_by_id(btf, type_id);
3374 
3375         btf_type_ops(t)->seq_show(btf, t, type_id, obj, 0, m);
3376 }
3377 
3378 #ifdef CONFIG_PROC_FS
3379 static void bpf_btf_show_fdinfo(struct seq_file *m, struct file *filp)
3380 {
3381         const struct btf *btf = filp->private_data;
3382 
3383         seq_printf(m, "btf_id:\t%u\n", btf->id);
3384 }
3385 #endif
3386 
3387 static int btf_release(struct inode *inode, struct file *filp)
3388 {
3389         btf_put(filp->private_data);
3390         return 0;
3391 }
3392 
3393 const struct file_operations btf_fops = {
3394 #ifdef CONFIG_PROC_FS
3395         .show_fdinfo    = bpf_btf_show_fdinfo,
3396 #endif
3397         .release        = btf_release,
3398 };
3399 
3400 static int __btf_new_fd(struct btf *btf)
3401 {
3402         return anon_inode_getfd("btf", &btf_fops, btf, O_RDONLY | O_CLOEXEC);
3403 }
3404 
3405 int btf_new_fd(const union bpf_attr *attr)
3406 {
3407         struct btf *btf;
3408         int ret;
3409 
3410         btf = btf_parse(u64_to_user_ptr(attr->btf),
3411                         attr->btf_size, attr->btf_log_level,
3412                         u64_to_user_ptr(attr->btf_log_buf),
3413                         attr->btf_log_size);
3414         if (IS_ERR(btf))
3415                 return PTR_ERR(btf);
3416 
3417         ret = btf_alloc_id(btf);
3418         if (ret) {
3419                 btf_free(btf);
3420                 return ret;
3421         }
3422 
3423         /*
3424          * The BTF ID is published to the userspace.
3425          * All BTF free must go through call_rcu() from
3426          * now on (i.e. free by calling btf_put()).
3427          */
3428 
3429         ret = __btf_new_fd(btf);
3430         if (ret < 0)
3431                 btf_put(btf);
3432 
3433         return ret;
3434 }
3435 
3436 struct btf *btf_get_by_fd(int fd)
3437 {
3438         struct btf *btf;
3439         struct fd f;
3440 
3441         f = fdget(fd);
3442 
3443         if (!f.file)
3444                 return ERR_PTR(-EBADF);
3445 
3446         if (f.file->f_op != &btf_fops) {
3447                 fdput(f);
3448                 return ERR_PTR(-EINVAL);
3449         }
3450 
3451         btf = f.file->private_data;
3452         refcount_inc(&btf->refcnt);
3453         fdput(f);
3454 
3455         return btf;
3456 }
3457 
3458 int btf_get_info_by_fd(const struct btf *btf,
3459                        const union bpf_attr *attr,
3460                        union bpf_attr __user *uattr)
3461 {
3462         struct bpf_btf_info __user *uinfo;
3463         struct bpf_btf_info info;
3464         u32 info_copy, btf_copy;
3465         void __user *ubtf;
3466         u32 uinfo_len;
3467 
3468         uinfo = u64_to_user_ptr(attr->info.info);
3469         uinfo_len = attr->info.info_len;
3470 
3471         info_copy = min_t(u32, uinfo_len, sizeof(info));
3472         memset(&info, 0, sizeof(info));
3473         if (copy_from_user(&info, uinfo, info_copy))
3474                 return -EFAULT;
3475 
3476         info.id = btf->id;
3477         ubtf = u64_to_user_ptr(info.btf);
3478         btf_copy = min_t(u32, btf->data_size, info.btf_size);
3479         if (copy_to_user(ubtf, btf->data, btf_copy))
3480                 return -EFAULT;
3481         info.btf_size = btf->data_size;
3482 
3483         if (copy_to_user(uinfo, &info, info_copy) ||
3484             put_user(info_copy, &uattr->info.info_len))
3485                 return -EFAULT;
3486 
3487         return 0;
3488 }
3489 
3490 int btf_get_fd_by_id(u32 id)
3491 {
3492         struct btf *btf;
3493         int fd;
3494 
3495         rcu_read_lock();
3496         btf = idr_find(&btf_idr, id);
3497         if (!btf || !refcount_inc_not_zero(&btf->refcnt))
3498                 btf = ERR_PTR(-ENOENT);
3499         rcu_read_unlock();
3500 
3501         if (IS_ERR(btf))
3502                 return PTR_ERR(btf);
3503 
3504         fd = __btf_new_fd(btf);
3505         if (fd < 0)
3506                 btf_put(btf);
3507 
3508         return fd;
3509 }
3510 
3511 u32 btf_id(const struct btf *btf)
3512 {
3513         return btf->id;
3514 }
/* [<][>][^][v][top][bottom][index][help] */
root/kernel/bpf/btf.c

DEFINITIONS
