1 /*
2 * Linux Socket Filter Data Structures
3 */
4 #ifndef __LINUX_FILTER_H__
5 #define __LINUX_FILTER_H__
6
7 #include <stdarg.h>
8
9 #include <linux/atomic.h>
10 #include <linux/compat.h>
11 #include <linux/skbuff.h>
12 #include <linux/linkage.h>
13 #include <linux/printk.h>
14 #include <linux/workqueue.h>
15 #include <linux/sched.h>
16 #include <net/sch_generic.h>
17
18 #include <asm/cacheflush.h>
19
20 #include <uapi/linux/filter.h>
21 #include <uapi/linux/bpf.h>
22
23 struct sk_buff;
24 struct sock;
25 struct seccomp_data;
26 struct bpf_prog_aux;
27
28 /* ArgX, context and stack frame pointer register positions. Note,
29 * Arg1, Arg2, Arg3, etc are used as argument mappings of function
30 * calls in BPF_CALL instruction.
31 */
32 #define BPF_REG_ARG1 BPF_REG_1
33 #define BPF_REG_ARG2 BPF_REG_2
34 #define BPF_REG_ARG3 BPF_REG_3
35 #define BPF_REG_ARG4 BPF_REG_4
36 #define BPF_REG_ARG5 BPF_REG_5
37 #define BPF_REG_CTX BPF_REG_6
38 #define BPF_REG_FP BPF_REG_10
39
40 /* Additional register mappings for converted user programs. */
41 #define BPF_REG_A BPF_REG_0
42 #define BPF_REG_X BPF_REG_7
43 #define BPF_REG_TMP BPF_REG_8
44
45 /* BPF program can access up to 512 bytes of stack space. */
46 #define MAX_BPF_STACK 512
47
48 /* Helper macros for filter block array initializers. */
49
50 /* ALU ops on registers, bpf_add|sub|...: dst_reg += src_reg */
51
52 #define BPF_ALU64_REG(OP, DST, SRC) \
53 ((struct bpf_insn) { \
54 .code = BPF_ALU64 | BPF_OP(OP) | BPF_X, \
55 .dst_reg = DST, \
56 .src_reg = SRC, \
57 .off = 0, \
58 .imm = 0 })
59
60 #define BPF_ALU32_REG(OP, DST, SRC) \
61 ((struct bpf_insn) { \
62 .code = BPF_ALU | BPF_OP(OP) | BPF_X, \
63 .dst_reg = DST, \
64 .src_reg = SRC, \
65 .off = 0, \
66 .imm = 0 })
67
68 /* ALU ops on immediates, bpf_add|sub|...: dst_reg += imm32 */
69
70 #define BPF_ALU64_IMM(OP, DST, IMM) \
71 ((struct bpf_insn) { \
72 .code = BPF_ALU64 | BPF_OP(OP) | BPF_K, \
73 .dst_reg = DST, \
74 .src_reg = 0, \
75 .off = 0, \
76 .imm = IMM })
77
78 #define BPF_ALU32_IMM(OP, DST, IMM) \
79 ((struct bpf_insn) { \
80 .code = BPF_ALU | BPF_OP(OP) | BPF_K, \
81 .dst_reg = DST, \
82 .src_reg = 0, \
83 .off = 0, \
84 .imm = IMM })
85
86 /* Endianess conversion, cpu_to_{l,b}e(), {l,b}e_to_cpu() */
87
88 #define BPF_ENDIAN(TYPE, DST, LEN) \
89 ((struct bpf_insn) { \
90 .code = BPF_ALU | BPF_END | BPF_SRC(TYPE), \
91 .dst_reg = DST, \
92 .src_reg = 0, \
93 .off = 0, \
94 .imm = LEN })
95
96 /* Short form of mov, dst_reg = src_reg */
97
98 #define BPF_MOV64_REG(DST, SRC) \
99 ((struct bpf_insn) { \
100 .code = BPF_ALU64 | BPF_MOV | BPF_X, \
101 .dst_reg = DST, \
102 .src_reg = SRC, \
103 .off = 0, \
104 .imm = 0 })
105
106 #define BPF_MOV32_REG(DST, SRC) \
107 ((struct bpf_insn) { \
108 .code = BPF_ALU | BPF_MOV | BPF_X, \
109 .dst_reg = DST, \
110 .src_reg = SRC, \
111 .off = 0, \
112 .imm = 0 })
113
114 /* Short form of mov, dst_reg = imm32 */
115
116 #define BPF_MOV64_IMM(DST, IMM) \
117 ((struct bpf_insn) { \
118 .code = BPF_ALU64 | BPF_MOV | BPF_K, \
119 .dst_reg = DST, \
120 .src_reg = 0, \
121 .off = 0, \
122 .imm = IMM })
123
124 #define BPF_MOV32_IMM(DST, IMM) \
125 ((struct bpf_insn) { \
126 .code = BPF_ALU | BPF_MOV | BPF_K, \
127 .dst_reg = DST, \
128 .src_reg = 0, \
129 .off = 0, \
130 .imm = IMM })
131
132 /* BPF_LD_IMM64 macro encodes single 'load 64-bit immediate' insn */
133 #define BPF_LD_IMM64(DST, IMM) \
134 BPF_LD_IMM64_RAW(DST, 0, IMM)
135
136 #define BPF_LD_IMM64_RAW(DST, SRC, IMM) \
137 ((struct bpf_insn) { \
138 .code = BPF_LD | BPF_DW | BPF_IMM, \
139 .dst_reg = DST, \
140 .src_reg = SRC, \
141 .off = 0, \
142 .imm = (__u32) (IMM) }), \
143 ((struct bpf_insn) { \
144 .code = 0, /* zero is reserved opcode */ \
145 .dst_reg = 0, \
146 .src_reg = 0, \
147 .off = 0, \
148 .imm = ((__u64) (IMM)) >> 32 })
149
150 /* pseudo BPF_LD_IMM64 insn used to refer to process-local map_fd */
151 #define BPF_LD_MAP_FD(DST, MAP_FD) \
152 BPF_LD_IMM64_RAW(DST, BPF_PSEUDO_MAP_FD, MAP_FD)
153
154 /* Short form of mov based on type, BPF_X: dst_reg = src_reg, BPF_K: dst_reg = imm32 */
155
156 #define BPF_MOV64_RAW(TYPE, DST, SRC, IMM) \
157 ((struct bpf_insn) { \
158 .code = BPF_ALU64 | BPF_MOV | BPF_SRC(TYPE), \
159 .dst_reg = DST, \
160 .src_reg = SRC, \
161 .off = 0, \
162 .imm = IMM })
163
164 #define BPF_MOV32_RAW(TYPE, DST, SRC, IMM) \
165 ((struct bpf_insn) { \
166 .code = BPF_ALU | BPF_MOV | BPF_SRC(TYPE), \
167 .dst_reg = DST, \
168 .src_reg = SRC, \
169 .off = 0, \
170 .imm = IMM })
171
172 /* Direct packet access, R0 = *(uint *) (skb->data + imm32) */
173
174 #define BPF_LD_ABS(SIZE, IMM) \
175 ((struct bpf_insn) { \
176 .code = BPF_LD | BPF_SIZE(SIZE) | BPF_ABS, \
177 .dst_reg = 0, \
178 .src_reg = 0, \
179 .off = 0, \
180 .imm = IMM })
181
182 /* Indirect packet access, R0 = *(uint *) (skb->data + src_reg + imm32) */
183
184 #define BPF_LD_IND(SIZE, SRC, IMM) \
185 ((struct bpf_insn) { \
186 .code = BPF_LD | BPF_SIZE(SIZE) | BPF_IND, \
187 .dst_reg = 0, \
188 .src_reg = SRC, \
189 .off = 0, \
190 .imm = IMM })
191
192 /* Memory load, dst_reg = *(uint *) (src_reg + off16) */
193
194 #define BPF_LDX_MEM(SIZE, DST, SRC, OFF) \
195 ((struct bpf_insn) { \
196 .code = BPF_LDX | BPF_SIZE(SIZE) | BPF_MEM, \
197 .dst_reg = DST, \
198 .src_reg = SRC, \
199 .off = OFF, \
200 .imm = 0 })
201
202 /* Memory store, *(uint *) (dst_reg + off16) = src_reg */
203
204 #define BPF_STX_MEM(SIZE, DST, SRC, OFF) \
205 ((struct bpf_insn) { \
206 .code = BPF_STX | BPF_SIZE(SIZE) | BPF_MEM, \
207 .dst_reg = DST, \
208 .src_reg = SRC, \
209 .off = OFF, \
210 .imm = 0 })
211
212 /* Atomic memory add, *(uint *)(dst_reg + off16) += src_reg */
213
214 #define BPF_STX_XADD(SIZE, DST, SRC, OFF) \
215 ((struct bpf_insn) { \
216 .code = BPF_STX | BPF_SIZE(SIZE) | BPF_XADD, \
217 .dst_reg = DST, \
218 .src_reg = SRC, \
219 .off = OFF, \
220 .imm = 0 })
221
222 /* Memory store, *(uint *) (dst_reg + off16) = imm32 */
223
224 #define BPF_ST_MEM(SIZE, DST, OFF, IMM) \
225 ((struct bpf_insn) { \
226 .code = BPF_ST | BPF_SIZE(SIZE) | BPF_MEM, \
227 .dst_reg = DST, \
228 .src_reg = 0, \
229 .off = OFF, \
230 .imm = IMM })
231
232 /* Conditional jumps against registers, if (dst_reg 'op' src_reg) goto pc + off16 */
233
234 #define BPF_JMP_REG(OP, DST, SRC, OFF) \
235 ((struct bpf_insn) { \
236 .code = BPF_JMP | BPF_OP(OP) | BPF_X, \
237 .dst_reg = DST, \
238 .src_reg = SRC, \
239 .off = OFF, \
240 .imm = 0 })
241
242 /* Conditional jumps against immediates, if (dst_reg 'op' imm32) goto pc + off16 */
243
244 #define BPF_JMP_IMM(OP, DST, IMM, OFF) \
245 ((struct bpf_insn) { \
246 .code = BPF_JMP | BPF_OP(OP) | BPF_K, \
247 .dst_reg = DST, \
248 .src_reg = 0, \
249 .off = OFF, \
250 .imm = IMM })
251
252 /* Function call */
253
254 #define BPF_EMIT_CALL(FUNC) \
255 ((struct bpf_insn) { \
256 .code = BPF_JMP | BPF_CALL, \
257 .dst_reg = 0, \
258 .src_reg = 0, \
259 .off = 0, \
260 .imm = ((FUNC) - __bpf_call_base) })
261
262 /* Raw code statement block */
263
264 #define BPF_RAW_INSN(CODE, DST, SRC, OFF, IMM) \
265 ((struct bpf_insn) { \
266 .code = CODE, \
267 .dst_reg = DST, \
268 .src_reg = SRC, \
269 .off = OFF, \
270 .imm = IMM })
271
272 /* Program exit */
273
274 #define BPF_EXIT_INSN() \
275 ((struct bpf_insn) { \
276 .code = BPF_JMP | BPF_EXIT, \
277 .dst_reg = 0, \
278 .src_reg = 0, \
279 .off = 0, \
280 .imm = 0 })
281
282 /* Internal classic blocks for direct assignment */
283
284 #define __BPF_STMT(CODE, K) \
285 ((struct sock_filter) BPF_STMT(CODE, K))
286
287 #define __BPF_JUMP(CODE, K, JT, JF) \
288 ((struct sock_filter) BPF_JUMP(CODE, K, JT, JF))
289
290 #define bytes_to_bpf_size(bytes) \
291 ({ \
292 int bpf_size = -EINVAL; \
293 \
294 if (bytes == sizeof(u8)) \
295 bpf_size = BPF_B; \
296 else if (bytes == sizeof(u16)) \
297 bpf_size = BPF_H; \
298 else if (bytes == sizeof(u32)) \
299 bpf_size = BPF_W; \
300 else if (bytes == sizeof(u64)) \
301 bpf_size = BPF_DW; \
302 \
303 bpf_size; \
304 })
305
306 #ifdef CONFIG_COMPAT
307 /* A struct sock_filter is architecture independent. */
308 struct compat_sock_fprog {
309 u16 len;
310 compat_uptr_t filter; /* struct sock_filter * */
311 };
312 #endif
313
314 struct sock_fprog_kern {
315 u16 len;
316 struct sock_filter *filter;
317 };
318
319 struct bpf_binary_header {
320 unsigned int pages;
321 u8 image[];
322 };
323
324 struct bpf_prog {
325 u16 pages; /* Number of allocated pages */
326 kmemcheck_bitfield_begin(meta);
327 u16 jited:1, /* Is our filter JIT'ed? */
328 gpl_compatible:1, /* Is filter GPL compatible? */
329 cb_access:1, /* Is control block accessed? */
330 dst_needed:1; /* Do we need dst entry? */
331 kmemcheck_bitfield_end(meta);
332 u32 len; /* Number of filter blocks */
333 enum bpf_prog_type type; /* Type of BPF program */
334 struct bpf_prog_aux *aux; /* Auxiliary fields */
335 struct sock_fprog_kern *orig_prog; /* Original BPF program */
336 unsigned int (*bpf_func)(const struct sk_buff *skb,
337 const struct bpf_insn *filter);
338 /* Instructions for interpreter */
339 union {
340 struct sock_filter insns[0];
341 struct bpf_insn insnsi[0];
342 };
343 };
344
345 struct sk_filter {
346 atomic_t refcnt;
347 struct rcu_head rcu;
348 struct bpf_prog *prog;
349 };
350
351 #define BPF_PROG_RUN(filter, ctx) (*filter->bpf_func)(ctx, filter->insnsi)
352
bpf_prog_run_save_cb(const struct bpf_prog * prog,struct sk_buff * skb)353 static inline u32 bpf_prog_run_save_cb(const struct bpf_prog *prog,
354 struct sk_buff *skb)
355 {
356 u8 *cb_data = qdisc_skb_cb(skb)->data;
357 u8 saved_cb[QDISC_CB_PRIV_LEN];
358 u32 res;
359
360 BUILD_BUG_ON(FIELD_SIZEOF(struct __sk_buff, cb) !=
361 QDISC_CB_PRIV_LEN);
362
363 if (unlikely(prog->cb_access)) {
364 memcpy(saved_cb, cb_data, sizeof(saved_cb));
365 memset(cb_data, 0, sizeof(saved_cb));
366 }
367
368 res = BPF_PROG_RUN(prog, skb);
369
370 if (unlikely(prog->cb_access))
371 memcpy(cb_data, saved_cb, sizeof(saved_cb));
372
373 return res;
374 }
375
bpf_prog_run_clear_cb(const struct bpf_prog * prog,struct sk_buff * skb)376 static inline u32 bpf_prog_run_clear_cb(const struct bpf_prog *prog,
377 struct sk_buff *skb)
378 {
379 u8 *cb_data = qdisc_skb_cb(skb)->data;
380
381 if (unlikely(prog->cb_access))
382 memset(cb_data, 0, QDISC_CB_PRIV_LEN);
383 return BPF_PROG_RUN(prog, skb);
384 }
385
bpf_prog_size(unsigned int proglen)386 static inline unsigned int bpf_prog_size(unsigned int proglen)
387 {
388 return max(sizeof(struct bpf_prog),
389 offsetof(struct bpf_prog, insns[proglen]));
390 }
391
bpf_prog_was_classic(const struct bpf_prog * prog)392 static inline bool bpf_prog_was_classic(const struct bpf_prog *prog)
393 {
394 /* When classic BPF programs have been loaded and the arch
395 * does not have a classic BPF JIT (anymore), they have been
396 * converted via bpf_migrate_filter() to eBPF and thus always
397 * have an unspec program type.
398 */
399 return prog->type == BPF_PROG_TYPE_UNSPEC;
400 }
401
402 #define bpf_classic_proglen(fprog) (fprog->len * sizeof(fprog->filter[0]))
403
404 #ifdef CONFIG_DEBUG_SET_MODULE_RONX
bpf_prog_lock_ro(struct bpf_prog * fp)405 static inline void bpf_prog_lock_ro(struct bpf_prog *fp)
406 {
407 set_memory_ro((unsigned long)fp, fp->pages);
408 }
409
bpf_prog_unlock_ro(struct bpf_prog * fp)410 static inline void bpf_prog_unlock_ro(struct bpf_prog *fp)
411 {
412 set_memory_rw((unsigned long)fp, fp->pages);
413 }
414 #else
bpf_prog_lock_ro(struct bpf_prog * fp)415 static inline void bpf_prog_lock_ro(struct bpf_prog *fp)
416 {
417 }
418
bpf_prog_unlock_ro(struct bpf_prog * fp)419 static inline void bpf_prog_unlock_ro(struct bpf_prog *fp)
420 {
421 }
422 #endif /* CONFIG_DEBUG_SET_MODULE_RONX */
423
424 int sk_filter(struct sock *sk, struct sk_buff *skb);
425
426 int bpf_prog_select_runtime(struct bpf_prog *fp);
427 void bpf_prog_free(struct bpf_prog *fp);
428
429 struct bpf_prog *bpf_prog_alloc(unsigned int size, gfp_t gfp_extra_flags);
430 struct bpf_prog *bpf_prog_realloc(struct bpf_prog *fp_old, unsigned int size,
431 gfp_t gfp_extra_flags);
432 void __bpf_prog_free(struct bpf_prog *fp);
433
bpf_prog_unlock_free(struct bpf_prog * fp)434 static inline void bpf_prog_unlock_free(struct bpf_prog *fp)
435 {
436 bpf_prog_unlock_ro(fp);
437 __bpf_prog_free(fp);
438 }
439
440 typedef int (*bpf_aux_classic_check_t)(struct sock_filter *filter,
441 unsigned int flen);
442
443 int bpf_prog_create(struct bpf_prog **pfp, struct sock_fprog_kern *fprog);
444 int bpf_prog_create_from_user(struct bpf_prog **pfp, struct sock_fprog *fprog,
445 bpf_aux_classic_check_t trans, bool save_orig);
446 void bpf_prog_destroy(struct bpf_prog *fp);
447
448 int sk_attach_filter(struct sock_fprog *fprog, struct sock *sk);
449 int __sk_attach_filter(struct sock_fprog *fprog, struct sock *sk,
450 bool locked);
451 int sk_attach_bpf(u32 ufd, struct sock *sk);
452 int sk_detach_filter(struct sock *sk);
453 int __sk_detach_filter(struct sock *sk, bool locked);
454
455 int sk_get_filter(struct sock *sk, struct sock_filter __user *filter,
456 unsigned int len);
457
458 bool sk_filter_charge(struct sock *sk, struct sk_filter *fp);
459 void sk_filter_uncharge(struct sock *sk, struct sk_filter *fp);
460
461 u64 __bpf_call_base(u64 r1, u64 r2, u64 r3, u64 r4, u64 r5);
462 void bpf_int_jit_compile(struct bpf_prog *fp);
463 bool bpf_helper_changes_skb_data(void *func);
464
465 #ifdef CONFIG_BPF_JIT
466 typedef void (*bpf_jit_fill_hole_t)(void *area, unsigned int size);
467
468 struct bpf_binary_header *
469 bpf_jit_binary_alloc(unsigned int proglen, u8 **image_ptr,
470 unsigned int alignment,
471 bpf_jit_fill_hole_t bpf_fill_ill_insns);
472 void bpf_jit_binary_free(struct bpf_binary_header *hdr);
473
474 void bpf_jit_compile(struct bpf_prog *fp);
475 void bpf_jit_free(struct bpf_prog *fp);
476
bpf_jit_dump(unsigned int flen,unsigned int proglen,u32 pass,void * image)477 static inline void bpf_jit_dump(unsigned int flen, unsigned int proglen,
478 u32 pass, void *image)
479 {
480 pr_err("flen=%u proglen=%u pass=%u image=%pK from=%s pid=%d\n", flen,
481 proglen, pass, image, current->comm, task_pid_nr(current));
482
483 if (image)
484 print_hex_dump(KERN_ERR, "JIT code: ", DUMP_PREFIX_OFFSET,
485 16, 1, image, proglen, false);
486 }
487 #else
bpf_jit_compile(struct bpf_prog * fp)488 static inline void bpf_jit_compile(struct bpf_prog *fp)
489 {
490 }
491
bpf_jit_free(struct bpf_prog * fp)492 static inline void bpf_jit_free(struct bpf_prog *fp)
493 {
494 bpf_prog_unlock_free(fp);
495 }
496 #endif /* CONFIG_BPF_JIT */
497
498 #define BPF_ANC BIT(15)
499
bpf_needs_clear_a(const struct sock_filter * first)500 static inline bool bpf_needs_clear_a(const struct sock_filter *first)
501 {
502 switch (first->code) {
503 case BPF_RET | BPF_K:
504 case BPF_LD | BPF_W | BPF_LEN:
505 return false;
506
507 case BPF_LD | BPF_W | BPF_ABS:
508 case BPF_LD | BPF_H | BPF_ABS:
509 case BPF_LD | BPF_B | BPF_ABS:
510 if (first->k == SKF_AD_OFF + SKF_AD_ALU_XOR_X)
511 return true;
512 return false;
513
514 default:
515 return true;
516 }
517 }
518
bpf_anc_helper(const struct sock_filter * ftest)519 static inline u16 bpf_anc_helper(const struct sock_filter *ftest)
520 {
521 BUG_ON(ftest->code & BPF_ANC);
522
523 switch (ftest->code) {
524 case BPF_LD | BPF_W | BPF_ABS:
525 case BPF_LD | BPF_H | BPF_ABS:
526 case BPF_LD | BPF_B | BPF_ABS:
527 #define BPF_ANCILLARY(CODE) case SKF_AD_OFF + SKF_AD_##CODE: \
528 return BPF_ANC | SKF_AD_##CODE
529 switch (ftest->k) {
530 BPF_ANCILLARY(PROTOCOL);
531 BPF_ANCILLARY(PKTTYPE);
532 BPF_ANCILLARY(IFINDEX);
533 BPF_ANCILLARY(NLATTR);
534 BPF_ANCILLARY(NLATTR_NEST);
535 BPF_ANCILLARY(MARK);
536 BPF_ANCILLARY(QUEUE);
537 BPF_ANCILLARY(HATYPE);
538 BPF_ANCILLARY(RXHASH);
539 BPF_ANCILLARY(CPU);
540 BPF_ANCILLARY(ALU_XOR_X);
541 BPF_ANCILLARY(VLAN_TAG);
542 BPF_ANCILLARY(VLAN_TAG_PRESENT);
543 BPF_ANCILLARY(PAY_OFFSET);
544 BPF_ANCILLARY(RANDOM);
545 BPF_ANCILLARY(VLAN_TPID);
546 }
547 /* Fallthrough. */
548 default:
549 return ftest->code;
550 }
551 }
552
553 void *bpf_internal_load_pointer_neg_helper(const struct sk_buff *skb,
554 int k, unsigned int size);
555
bpf_load_pointer(const struct sk_buff * skb,int k,unsigned int size,void * buffer)556 static inline void *bpf_load_pointer(const struct sk_buff *skb, int k,
557 unsigned int size, void *buffer)
558 {
559 if (k >= 0)
560 return skb_header_pointer(skb, k, size, buffer);
561
562 return bpf_internal_load_pointer_neg_helper(skb, k, size);
563 }
564
bpf_tell_extensions(void)565 static inline int bpf_tell_extensions(void)
566 {
567 return SKF_AD_MAX;
568 }
569
570 #endif /* __LINUX_FILTER_H__ */
571