fs/binfmt_flat.c

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This source file includes following definitions.
flat_core_dump
create_flat_tables
decompress_exec
calc_reloc
old_reloc
load_flat_file
load_flat_shared_library
load_flat_binary
init_flat_binfmt
   1 // SPDX-License-Identifier: GPL-2.0
   2 /****************************************************************************/
   3 /*
   4  *  linux/fs/binfmt_flat.c
   5  *
   6  *      Copyright (C) 2000-2003 David McCullough <davidm@snapgear.com>
   7  *      Copyright (C) 2002 Greg Ungerer <gerg@snapgear.com>
   8  *      Copyright (C) 2002 SnapGear, by Paul Dale <pauli@snapgear.com>
   9  *      Copyright (C) 2000, 2001 Lineo, by David McCullough <davidm@lineo.com>
  10  *  based heavily on:
  11  *
  12  *  linux/fs/binfmt_aout.c:
  13  *      Copyright (C) 1991, 1992, 1996  Linus Torvalds
  14  *  linux/fs/binfmt_flat.c for 2.0 kernel
  15  *          Copyright (C) 1998  Kenneth Albanowski <kjahds@kjahds.com>
  16  *      JAN/99 -- coded full program relocation (gerg@snapgear.com)
  17  */
  18 
  19 #define pr_fmt(fmt)     KBUILD_MODNAME ": " fmt
  20 
  21 #include <linux/kernel.h>
  22 #include <linux/sched.h>
  23 #include <linux/sched/task_stack.h>
  24 #include <linux/mm.h>
  25 #include <linux/mman.h>
  26 #include <linux/errno.h>
  27 #include <linux/signal.h>
  28 #include <linux/string.h>
  29 #include <linux/fs.h>
  30 #include <linux/file.h>
  31 #include <linux/ptrace.h>
  32 #include <linux/user.h>
  33 #include <linux/slab.h>
  34 #include <linux/binfmts.h>
  35 #include <linux/personality.h>
  36 #include <linux/init.h>
  37 #include <linux/flat.h>
  38 #include <linux/uaccess.h>
  39 #include <linux/vmalloc.h>
  40 
  41 #include <asm/byteorder.h>
  42 #include <asm/unaligned.h>
  43 #include <asm/cacheflush.h>
  44 #include <asm/page.h>
  45 #include <asm/flat.h>
  46 
  47 #ifndef flat_get_relocate_addr
  48 #define flat_get_relocate_addr(rel)     (rel)
  49 #endif
  50 
  51 /****************************************************************************/
  52 
  53 /*
  54  * User data (data section and bss) needs to be aligned.
  55  * We pick 0x20 here because it is the max value elf2flt has always
  56  * used in producing FLAT files, and because it seems to be large
  57  * enough to make all the gcc alignment related tests happy.
  58  */
  59 #define FLAT_DATA_ALIGN (0x20)
  60 
  61 /*
  62  * User data (stack) also needs to be aligned.
  63  * Here we can be a bit looser than the data sections since this
  64  * needs to only meet arch ABI requirements.
  65  */
  66 #define FLAT_STACK_ALIGN        max_t(unsigned long, sizeof(void *), ARCH_SLAB_MINALIGN)
  67 
  68 #define RELOC_FAILED 0xff00ff01         /* Relocation incorrect somewhere */
  69 #define UNLOADED_LIB 0x7ff000ff         /* Placeholder for unused library */
  70 
  71 #ifdef CONFIG_BINFMT_SHARED_FLAT
  72 #define MAX_SHARED_LIBS                 (4)
  73 #else
  74 #define MAX_SHARED_LIBS                 (1)
  75 #endif
  76 
  77 struct lib_info {
  78         struct {
  79                 unsigned long start_code;               /* Start of text segment */
  80                 unsigned long start_data;               /* Start of data segment */
  81                 unsigned long start_brk;                /* End of data segment */
  82                 unsigned long text_len;                 /* Length of text segment */
  83                 unsigned long entry;                    /* Start address for this module */
  84                 unsigned long build_date;               /* When this one was compiled */
  85                 bool loaded;                            /* Has this library been loaded? */
  86         } lib_list[MAX_SHARED_LIBS];
  87 };
  88 
  89 #ifdef CONFIG_BINFMT_SHARED_FLAT
  90 static int load_flat_shared_library(int id, struct lib_info *p);
  91 #endif
  92 
  93 static int load_flat_binary(struct linux_binprm *);
  94 static int flat_core_dump(struct coredump_params *cprm);
  95 
  96 static struct linux_binfmt flat_format = {
  97         .module         = THIS_MODULE,
  98         .load_binary    = load_flat_binary,
  99         .core_dump      = flat_core_dump,
 100         .min_coredump   = PAGE_SIZE
 101 };
 102 
 103 /****************************************************************************/
 104 /*
 105  * Routine writes a core dump image in the current directory.
 106  * Currently only a stub-function.
 107  */
 108 
 109 static int flat_core_dump(struct coredump_params *cprm)
 110 {
 111         pr_warn("Process %s:%d received signr %d and should have core dumped\n",
 112                 current->comm, current->pid, cprm->siginfo->si_signo);
 113         return 1;
 114 }
 115 
 116 /****************************************************************************/
 117 /*
 118  * create_flat_tables() parses the env- and arg-strings in new user
 119  * memory and creates the pointer tables from them, and puts their
 120  * addresses on the "stack", recording the new stack pointer value.
 121  */
 122 
 123 static int create_flat_tables(struct linux_binprm *bprm, unsigned long arg_start)
 124 {
 125         char __user *p;
 126         unsigned long __user *sp;
 127         long i, len;
 128 
 129         p = (char __user *)arg_start;
 130         sp = (unsigned long __user *)current->mm->start_stack;
 131 
 132         sp -= bprm->envc + 1;
 133         sp -= bprm->argc + 1;
 134         if (IS_ENABLED(CONFIG_BINFMT_FLAT_ARGVP_ENVP_ON_STACK))
 135                 sp -= 2; /* argvp + envp */
 136         sp -= 1;  /* &argc */
 137 
 138         current->mm->start_stack = (unsigned long)sp & -FLAT_STACK_ALIGN;
 139         sp = (unsigned long __user *)current->mm->start_stack;
 140 
 141         __put_user(bprm->argc, sp++);
 142         if (IS_ENABLED(CONFIG_BINFMT_FLAT_ARGVP_ENVP_ON_STACK)) {
 143                 unsigned long argv, envp;
 144                 argv = (unsigned long)(sp + 2);
 145                 envp = (unsigned long)(sp + 2 + bprm->argc + 1);
 146                 __put_user(argv, sp++);
 147                 __put_user(envp, sp++);
 148         }
 149 
 150         current->mm->arg_start = (unsigned long)p;
 151         for (i = bprm->argc; i > 0; i--) {
 152                 __put_user((unsigned long)p, sp++);
 153                 len = strnlen_user(p, MAX_ARG_STRLEN);
 154                 if (!len || len > MAX_ARG_STRLEN)
 155                         return -EINVAL;
 156                 p += len;
 157         }
 158         __put_user(0, sp++);
 159         current->mm->arg_end = (unsigned long)p;
 160 
 161         current->mm->env_start = (unsigned long) p;
 162         for (i = bprm->envc; i > 0; i--) {
 163                 __put_user((unsigned long)p, sp++);
 164                 len = strnlen_user(p, MAX_ARG_STRLEN);
 165                 if (!len || len > MAX_ARG_STRLEN)
 166                         return -EINVAL;
 167                 p += len;
 168         }
 169         __put_user(0, sp++);
 170         current->mm->env_end = (unsigned long)p;
 171 
 172         return 0;
 173 }
 174 
 175 /****************************************************************************/
 176 
 177 #ifdef CONFIG_BINFMT_ZFLAT
 178 
 179 #include <linux/zlib.h>
 180 
 181 #define LBUFSIZE        4000
 182 
 183 /* gzip flag byte */
 184 #define ASCII_FLAG   0x01 /* bit 0 set: file probably ASCII text */
 185 #define CONTINUATION 0x02 /* bit 1 set: continuation of multi-part gzip file */
 186 #define EXTRA_FIELD  0x04 /* bit 2 set: extra field present */
 187 #define ORIG_NAME    0x08 /* bit 3 set: original file name present */
 188 #define COMMENT      0x10 /* bit 4 set: file comment present */
 189 #define ENCRYPTED    0x20 /* bit 5 set: file is encrypted */
 190 #define RESERVED     0xC0 /* bit 6,7:   reserved */
 191 
 192 static int decompress_exec(struct linux_binprm *bprm, loff_t fpos, char *dst,
 193                 long len, int fd)
 194 {
 195         unsigned char *buf;
 196         z_stream strm;
 197         int ret, retval;
 198 
 199         pr_debug("decompress_exec(offset=%llx,buf=%p,len=%lx)\n", fpos, dst, len);
 200 
 201         memset(&strm, 0, sizeof(strm));
 202         strm.workspace = kmalloc(zlib_inflate_workspacesize(), GFP_KERNEL);
 203         if (!strm.workspace)
 204                 return -ENOMEM;
 205 
 206         buf = kmalloc(LBUFSIZE, GFP_KERNEL);
 207         if (!buf) {
 208                 retval = -ENOMEM;
 209                 goto out_free;
 210         }
 211 
 212         /* Read in first chunk of data and parse gzip header. */
 213         ret = kernel_read(bprm->file, buf, LBUFSIZE, &fpos);
 214 
 215         strm.next_in = buf;
 216         strm.avail_in = ret;
 217         strm.total_in = 0;
 218 
 219         retval = -ENOEXEC;
 220 
 221         /* Check minimum size -- gzip header */
 222         if (ret < 10) {
 223                 pr_debug("file too small?\n");
 224                 goto out_free_buf;
 225         }
 226 
 227         /* Check gzip magic number */
 228         if ((buf[0] != 037) || ((buf[1] != 0213) && (buf[1] != 0236))) {
 229                 pr_debug("unknown compression magic?\n");
 230                 goto out_free_buf;
 231         }
 232 
 233         /* Check gzip method */
 234         if (buf[2] != 8) {
 235                 pr_debug("unknown compression method?\n");
 236                 goto out_free_buf;
 237         }
 238         /* Check gzip flags */
 239         if ((buf[3] & ENCRYPTED) || (buf[3] & CONTINUATION) ||
 240             (buf[3] & RESERVED)) {
 241                 pr_debug("unknown flags?\n");
 242                 goto out_free_buf;
 243         }
 244 
 245         ret = 10;
 246         if (buf[3] & EXTRA_FIELD) {
 247                 ret += 2 + buf[10] + (buf[11] << 8);
 248                 if (unlikely(ret >= LBUFSIZE)) {
 249                         pr_debug("buffer overflow (EXTRA)?\n");
 250                         goto out_free_buf;
 251                 }
 252         }
 253         if (buf[3] & ORIG_NAME) {
 254                 while (ret < LBUFSIZE && buf[ret++] != 0)
 255                         ;
 256                 if (unlikely(ret == LBUFSIZE)) {
 257                         pr_debug("buffer overflow (ORIG_NAME)?\n");
 258                         goto out_free_buf;
 259                 }
 260         }
 261         if (buf[3] & COMMENT) {
 262                 while (ret < LBUFSIZE && buf[ret++] != 0)
 263                         ;
 264                 if (unlikely(ret == LBUFSIZE)) {
 265                         pr_debug("buffer overflow (COMMENT)?\n");
 266                         goto out_free_buf;
 267                 }
 268         }
 269 
 270         strm.next_in += ret;
 271         strm.avail_in -= ret;
 272 
 273         strm.next_out = dst;
 274         strm.avail_out = len;
 275         strm.total_out = 0;
 276 
 277         if (zlib_inflateInit2(&strm, -MAX_WBITS) != Z_OK) {
 278                 pr_debug("zlib init failed?\n");
 279                 goto out_free_buf;
 280         }
 281 
 282         while ((ret = zlib_inflate(&strm, Z_NO_FLUSH)) == Z_OK) {
 283                 ret = kernel_read(bprm->file, buf, LBUFSIZE, &fpos);
 284                 if (ret <= 0)
 285                         break;
 286                 len -= ret;
 287 
 288                 strm.next_in = buf;
 289                 strm.avail_in = ret;
 290                 strm.total_in = 0;
 291         }
 292 
 293         if (ret < 0) {
 294                 pr_debug("decompression failed (%d), %s\n",
 295                         ret, strm.msg);
 296                 goto out_zlib;
 297         }
 298 
 299         retval = 0;
 300 out_zlib:
 301         zlib_inflateEnd(&strm);
 302 out_free_buf:
 303         kfree(buf);
 304 out_free:
 305         kfree(strm.workspace);
 306         return retval;
 307 }
 308 
 309 #endif /* CONFIG_BINFMT_ZFLAT */
 310 
 311 /****************************************************************************/
 312 
 313 static unsigned long
 314 calc_reloc(unsigned long r, struct lib_info *p, int curid, int internalp)
 315 {
 316         unsigned long addr;
 317         int id;
 318         unsigned long start_brk;
 319         unsigned long start_data;
 320         unsigned long text_len;
 321         unsigned long start_code;
 322 
 323 #ifdef CONFIG_BINFMT_SHARED_FLAT
 324         if (r == 0)
 325                 id = curid;     /* Relocs of 0 are always self referring */
 326         else {
 327                 id = (r >> 24) & 0xff;  /* Find ID for this reloc */
 328                 r &= 0x00ffffff;        /* Trim ID off here */
 329         }
 330         if (id >= MAX_SHARED_LIBS) {
 331                 pr_err("reference 0x%lx to shared library %d", r, id);
 332                 goto failed;
 333         }
 334         if (curid != id) {
 335                 if (internalp) {
 336                         pr_err("reloc address 0x%lx not in same module "
 337                                "(%d != %d)", r, curid, id);
 338                         goto failed;
 339                 } else if (!p->lib_list[id].loaded &&
 340                            load_flat_shared_library(id, p) < 0) {
 341                         pr_err("failed to load library %d", id);
 342                         goto failed;
 343                 }
 344                 /* Check versioning information (i.e. time stamps) */
 345                 if (p->lib_list[id].build_date && p->lib_list[curid].build_date &&
 346                                 p->lib_list[curid].build_date < p->lib_list[id].build_date) {
 347                         pr_err("library %d is younger than %d", id, curid);
 348                         goto failed;
 349                 }
 350         }
 351 #else
 352         id = 0;
 353 #endif
 354 
 355         start_brk = p->lib_list[id].start_brk;
 356         start_data = p->lib_list[id].start_data;
 357         start_code = p->lib_list[id].start_code;
 358         text_len = p->lib_list[id].text_len;
 359 
 360         if (r > start_brk - start_data + text_len) {
 361                 pr_err("reloc outside program 0x%lx (0 - 0x%lx/0x%lx)",
 362                        r, start_brk-start_data+text_len, text_len);
 363                 goto failed;
 364         }
 365 
 366         if (r < text_len)                       /* In text segment */
 367                 addr = r + start_code;
 368         else                                    /* In data segment */
 369                 addr = r - text_len + start_data;
 370 
 371         /* Range checked already above so doing the range tests is redundant...*/
 372         return addr;
 373 
 374 failed:
 375         pr_cont(", killing %s!\n", current->comm);
 376         send_sig(SIGSEGV, current, 0);
 377 
 378         return RELOC_FAILED;
 379 }
 380 
 381 /****************************************************************************/
 382 
 383 #ifdef CONFIG_BINFMT_FLAT_OLD
 384 static void old_reloc(unsigned long rl)
 385 {
 386         static const char *segment[] = { "TEXT", "DATA", "BSS", "*UNKNOWN*" };
 387         flat_v2_reloc_t r;
 388         unsigned long __user *ptr;
 389         unsigned long val;
 390 
 391         r.value = rl;
 392 #if defined(CONFIG_COLDFIRE)
 393         ptr = (unsigned long __user *)(current->mm->start_code + r.reloc.offset);
 394 #else
 395         ptr = (unsigned long __user *)(current->mm->start_data + r.reloc.offset);
 396 #endif
 397         get_user(val, ptr);
 398 
 399         pr_debug("Relocation of variable at DATASEG+%x "
 400                  "(address %p, currently %lx) into segment %s\n",
 401                  r.reloc.offset, ptr, val, segment[r.reloc.type]);
 402 
 403         switch (r.reloc.type) {
 404         case OLD_FLAT_RELOC_TYPE_TEXT:
 405                 val += current->mm->start_code;
 406                 break;
 407         case OLD_FLAT_RELOC_TYPE_DATA:
 408                 val += current->mm->start_data;
 409                 break;
 410         case OLD_FLAT_RELOC_TYPE_BSS:
 411                 val += current->mm->end_data;
 412                 break;
 413         default:
 414                 pr_err("Unknown relocation type=%x\n", r.reloc.type);
 415                 break;
 416         }
 417         put_user(val, ptr);
 418 
 419         pr_debug("Relocation became %lx\n", val);
 420 }
 421 #endif /* CONFIG_BINFMT_FLAT_OLD */
 422 
 423 /****************************************************************************/
 424 
 425 static int load_flat_file(struct linux_binprm *bprm,
 426                 struct lib_info *libinfo, int id, unsigned long *extra_stack)
 427 {
 428         struct flat_hdr *hdr;
 429         unsigned long textpos, datapos, realdatastart;
 430         u32 text_len, data_len, bss_len, stack_len, full_data, flags;
 431         unsigned long len, memp, memp_size, extra, rlim;
 432         __be32 __user *reloc;
 433         u32 __user *rp;
 434         int i, rev, relocs;
 435         loff_t fpos;
 436         unsigned long start_code, end_code;
 437         ssize_t result;
 438         int ret;
 439 
 440         hdr = ((struct flat_hdr *) bprm->buf);          /* exec-header */
 441 
 442         text_len  = ntohl(hdr->data_start);
 443         data_len  = ntohl(hdr->data_end) - ntohl(hdr->data_start);
 444         bss_len   = ntohl(hdr->bss_end) - ntohl(hdr->data_end);
 445         stack_len = ntohl(hdr->stack_size);
 446         if (extra_stack) {
 447                 stack_len += *extra_stack;
 448                 *extra_stack = stack_len;
 449         }
 450         relocs    = ntohl(hdr->reloc_count);
 451         flags     = ntohl(hdr->flags);
 452         rev       = ntohl(hdr->rev);
 453         full_data = data_len + relocs * sizeof(unsigned long);
 454 
 455         if (strncmp(hdr->magic, "bFLT", 4)) {
 456                 /*
 457                  * Previously, here was a printk to tell people
 458                  *   "BINFMT_FLAT: bad header magic".
 459                  * But for the kernel which also use ELF FD-PIC format, this
 460                  * error message is confusing.
 461                  * because a lot of people do not manage to produce good
 462                  */
 463                 ret = -ENOEXEC;
 464                 goto err;
 465         }
 466 
 467         if (flags & FLAT_FLAG_KTRACE)
 468                 pr_info("Loading file: %s\n", bprm->filename);
 469 
 470 #ifdef CONFIG_BINFMT_FLAT_OLD
 471         if (rev != FLAT_VERSION && rev != OLD_FLAT_VERSION) {
 472                 pr_err("bad flat file version 0x%x (supported 0x%lx and 0x%lx)\n",
 473                        rev, FLAT_VERSION, OLD_FLAT_VERSION);
 474                 ret = -ENOEXEC;
 475                 goto err;
 476         }
 477 
 478         /* Don't allow old format executables to use shared libraries */
 479         if (rev == OLD_FLAT_VERSION && id != 0) {
 480                 pr_err("shared libraries are not available before rev 0x%lx\n",
 481                        FLAT_VERSION);
 482                 ret = -ENOEXEC;
 483                 goto err;
 484         }
 485 
 486         /*
 487          * fix up the flags for the older format,  there were all kinds
 488          * of endian hacks,  this only works for the simple cases
 489          */
 490         if (rev == OLD_FLAT_VERSION &&
 491            (flags || IS_ENABLED(CONFIG_BINFMT_FLAT_OLD_ALWAYS_RAM)))
 492                 flags = FLAT_FLAG_RAM;
 493 
 494 #else /* CONFIG_BINFMT_FLAT_OLD */
 495         if (rev != FLAT_VERSION) {
 496                 pr_err("bad flat file version 0x%x (supported 0x%lx)\n",
 497                        rev, FLAT_VERSION);
 498                 ret = -ENOEXEC;
 499                 goto err;
 500         }
 501 #endif /* !CONFIG_BINFMT_FLAT_OLD */
 502 
 503         /*
 504          * Make sure the header params are sane.
 505          * 28 bits (256 MB) is way more than reasonable in this case.
 506          * If some top bits are set we have probable binary corruption.
 507         */
 508         if ((text_len | data_len | bss_len | stack_len | full_data) >> 28) {
 509                 pr_err("bad header\n");
 510                 ret = -ENOEXEC;
 511                 goto err;
 512         }
 513 
 514 #ifndef CONFIG_BINFMT_ZFLAT
 515         if (flags & (FLAT_FLAG_GZIP|FLAT_FLAG_GZDATA)) {
 516                 pr_err("Support for ZFLAT executables is not enabled.\n");
 517                 ret = -ENOEXEC;
 518                 goto err;
 519         }
 520 #endif
 521 
 522         /*
 523          * Check initial limits. This avoids letting people circumvent
 524          * size limits imposed on them by creating programs with large
 525          * arrays in the data or bss.
 526          */
 527         rlim = rlimit(RLIMIT_DATA);
 528         if (rlim >= RLIM_INFINITY)
 529                 rlim = ~0;
 530         if (data_len + bss_len > rlim) {
 531                 ret = -ENOMEM;
 532                 goto err;
 533         }
 534 
 535         /* Flush all traces of the currently running executable */
 536         if (id == 0) {
 537                 ret = flush_old_exec(bprm);
 538                 if (ret)
 539                         goto err;
 540 
 541                 /* OK, This is the point of no return */
 542                 set_personality(PER_LINUX_32BIT);
 543                 setup_new_exec(bprm);
 544         }
 545 
 546         /*
 547          * calculate the extra space we need to map in
 548          */
 549         extra = max_t(unsigned long, bss_len + stack_len,
 550                         relocs * sizeof(unsigned long));
 551 
 552         /*
 553          * there are a couple of cases here,  the separate code/data
 554          * case,  and then the fully copied to RAM case which lumps
 555          * it all together.
 556          */
 557         if (!IS_ENABLED(CONFIG_MMU) && !(flags & (FLAT_FLAG_RAM|FLAT_FLAG_GZIP))) {
 558                 /*
 559                  * this should give us a ROM ptr,  but if it doesn't we don't
 560                  * really care
 561                  */
 562                 pr_debug("ROM mapping of file (we hope)\n");
 563 
 564                 textpos = vm_mmap(bprm->file, 0, text_len, PROT_READ|PROT_EXEC,
 565                                   MAP_PRIVATE|MAP_EXECUTABLE, 0);
 566                 if (!textpos || IS_ERR_VALUE(textpos)) {
 567                         ret = textpos;
 568                         if (!textpos)
 569                                 ret = -ENOMEM;
 570                         pr_err("Unable to mmap process text, errno %d\n", ret);
 571                         goto err;
 572                 }
 573 
 574                 len = data_len + extra;
 575                 len = PAGE_ALIGN(len);
 576                 realdatastart = vm_mmap(NULL, 0, len,
 577                         PROT_READ|PROT_WRITE|PROT_EXEC, MAP_PRIVATE, 0);
 578 
 579                 if (realdatastart == 0 || IS_ERR_VALUE(realdatastart)) {
 580                         ret = realdatastart;
 581                         if (!realdatastart)
 582                                 ret = -ENOMEM;
 583                         pr_err("Unable to allocate RAM for process data, "
 584                                "errno %d\n", ret);
 585                         vm_munmap(textpos, text_len);
 586                         goto err;
 587                 }
 588                 datapos = ALIGN(realdatastart, FLAT_DATA_ALIGN);
 589 
 590                 pr_debug("Allocated data+bss+stack (%u bytes): %lx\n",
 591                          data_len + bss_len + stack_len, datapos);
 592 
 593                 fpos = ntohl(hdr->data_start);
 594 #ifdef CONFIG_BINFMT_ZFLAT
 595                 if (flags & FLAT_FLAG_GZDATA) {
 596                         result = decompress_exec(bprm, fpos, (char *)datapos,
 597                                                  full_data, 0);
 598                 } else
 599 #endif
 600                 {
 601                         result = read_code(bprm->file, datapos, fpos,
 602                                         full_data);
 603                 }
 604                 if (IS_ERR_VALUE(result)) {
 605                         ret = result;
 606                         pr_err("Unable to read data+bss, errno %d\n", ret);
 607                         vm_munmap(textpos, text_len);
 608                         vm_munmap(realdatastart, len);
 609                         goto err;
 610                 }
 611 
 612                 reloc = (__be32 __user *)
 613                         (datapos + (ntohl(hdr->reloc_start) - text_len));
 614                 memp = realdatastart;
 615                 memp_size = len;
 616         } else {
 617 
 618                 len = text_len + data_len + extra;
 619                 len = PAGE_ALIGN(len);
 620                 textpos = vm_mmap(NULL, 0, len,
 621                         PROT_READ | PROT_EXEC | PROT_WRITE, MAP_PRIVATE, 0);
 622 
 623                 if (!textpos || IS_ERR_VALUE(textpos)) {
 624                         ret = textpos;
 625                         if (!textpos)
 626                                 ret = -ENOMEM;
 627                         pr_err("Unable to allocate RAM for process text/data, "
 628                                "errno %d\n", ret);
 629                         goto err;
 630                 }
 631 
 632                 realdatastart = textpos + ntohl(hdr->data_start);
 633                 datapos = ALIGN(realdatastart, FLAT_DATA_ALIGN);
 634 
 635                 reloc = (__be32 __user *)
 636                         (datapos + (ntohl(hdr->reloc_start) - text_len));
 637                 memp = textpos;
 638                 memp_size = len;
 639 #ifdef CONFIG_BINFMT_ZFLAT
 640                 /*
 641                  * load it all in and treat it like a RAM load from now on
 642                  */
 643                 if (flags & FLAT_FLAG_GZIP) {
 644 #ifndef CONFIG_MMU
 645                         result = decompress_exec(bprm, sizeof(struct flat_hdr),
 646                                          (((char *)textpos) + sizeof(struct flat_hdr)),
 647                                          (text_len + full_data
 648                                                   - sizeof(struct flat_hdr)),
 649                                          0);
 650                         if (datapos != realdatastart)
 651                                 memmove((void *)datapos, (void *)realdatastart,
 652                                                 full_data);
 653 #else
 654                         /*
 655                          * This is used on MMU systems mainly for testing.
 656                          * Let's use a kernel buffer to simplify things.
 657                          */
 658                         long unz_text_len = text_len - sizeof(struct flat_hdr);
 659                         long unz_len = unz_text_len + full_data;
 660                         char *unz_data = vmalloc(unz_len);
 661                         if (!unz_data) {
 662                                 result = -ENOMEM;
 663                         } else {
 664                                 result = decompress_exec(bprm, sizeof(struct flat_hdr),
 665                                                          unz_data, unz_len, 0);
 666                                 if (result == 0 &&
 667                                     (copy_to_user((void __user *)textpos + sizeof(struct flat_hdr),
 668                                                   unz_data, unz_text_len) ||
 669                                      copy_to_user((void __user *)datapos,
 670                                                   unz_data + unz_text_len, full_data)))
 671                                         result = -EFAULT;
 672                                 vfree(unz_data);
 673                         }
 674 #endif
 675                 } else if (flags & FLAT_FLAG_GZDATA) {
 676                         result = read_code(bprm->file, textpos, 0, text_len);
 677                         if (!IS_ERR_VALUE(result)) {
 678 #ifndef CONFIG_MMU
 679                                 result = decompress_exec(bprm, text_len, (char *) datapos,
 680                                                  full_data, 0);
 681 #else
 682                                 char *unz_data = vmalloc(full_data);
 683                                 if (!unz_data) {
 684                                         result = -ENOMEM;
 685                                 } else {
 686                                         result = decompress_exec(bprm, text_len,
 687                                                        unz_data, full_data, 0);
 688                                         if (result == 0 &&
 689                                             copy_to_user((void __user *)datapos,
 690                                                          unz_data, full_data))
 691                                                 result = -EFAULT;
 692                                         vfree(unz_data);
 693                                 }
 694 #endif
 695                         }
 696                 } else
 697 #endif /* CONFIG_BINFMT_ZFLAT */
 698                 {
 699                         result = read_code(bprm->file, textpos, 0, text_len);
 700                         if (!IS_ERR_VALUE(result))
 701                                 result = read_code(bprm->file, datapos,
 702                                                    ntohl(hdr->data_start),
 703                                                    full_data);
 704                 }
 705                 if (IS_ERR_VALUE(result)) {
 706                         ret = result;
 707                         pr_err("Unable to read code+data+bss, errno %d\n", ret);
 708                         vm_munmap(textpos, text_len + data_len + extra);
 709                         goto err;
 710                 }
 711         }
 712 
 713         start_code = textpos + sizeof(struct flat_hdr);
 714         end_code = textpos + text_len;
 715         text_len -= sizeof(struct flat_hdr); /* the real code len */
 716 
 717         /* The main program needs a little extra setup in the task structure */
 718         if (id == 0) {
 719                 current->mm->start_code = start_code;
 720                 current->mm->end_code = end_code;
 721                 current->mm->start_data = datapos;
 722                 current->mm->end_data = datapos + data_len;
 723                 /*
 724                  * set up the brk stuff, uses any slack left in data/bss/stack
 725                  * allocation.  We put the brk after the bss (between the bss
 726                  * and stack) like other platforms.
 727                  * Userspace code relies on the stack pointer starting out at
 728                  * an address right at the end of a page.
 729                  */
 730                 current->mm->start_brk = datapos + data_len + bss_len;
 731                 current->mm->brk = (current->mm->start_brk + 3) & ~3;
 732 #ifndef CONFIG_MMU
 733                 current->mm->context.end_brk = memp + memp_size - stack_len;
 734 #endif
 735         }
 736 
 737         if (flags & FLAT_FLAG_KTRACE) {
 738                 pr_info("Mapping is %lx, Entry point is %x, data_start is %x\n",
 739                         textpos, 0x00ffffff&ntohl(hdr->entry), ntohl(hdr->data_start));
 740                 pr_info("%s %s: TEXT=%lx-%lx DATA=%lx-%lx BSS=%lx-%lx\n",
 741                         id ? "Lib" : "Load", bprm->filename,
 742                         start_code, end_code, datapos, datapos + data_len,
 743                         datapos + data_len, (datapos + data_len + bss_len + 3) & ~3);
 744         }
 745 
 746         /* Store the current module values into the global library structure */
 747         libinfo->lib_list[id].start_code = start_code;
 748         libinfo->lib_list[id].start_data = datapos;
 749         libinfo->lib_list[id].start_brk = datapos + data_len + bss_len;
 750         libinfo->lib_list[id].text_len = text_len;
 751         libinfo->lib_list[id].loaded = 1;
 752         libinfo->lib_list[id].entry = (0x00ffffff & ntohl(hdr->entry)) + textpos;
 753         libinfo->lib_list[id].build_date = ntohl(hdr->build_date);
 754 
 755         /*
 756          * We just load the allocations into some temporary memory to
 757          * help simplify all this mumbo jumbo
 758          *
 759          * We've got two different sections of relocation entries.
 760          * The first is the GOT which resides at the beginning of the data segment
 761          * and is terminated with a -1.  This one can be relocated in place.
 762          * The second is the extra relocation entries tacked after the image's
 763          * data segment. These require a little more processing as the entry is
 764          * really an offset into the image which contains an offset into the
 765          * image.
 766          */
 767         if (flags & FLAT_FLAG_GOTPIC) {
 768                 for (rp = (u32 __user *)datapos; ; rp++) {
 769                         u32 addr, rp_val;
 770                         if (get_user(rp_val, rp))
 771                                 return -EFAULT;
 772                         if (rp_val == 0xffffffff)
 773                                 break;
 774                         if (rp_val) {
 775                                 addr = calc_reloc(rp_val, libinfo, id, 0);
 776                                 if (addr == RELOC_FAILED) {
 777                                         ret = -ENOEXEC;
 778                                         goto err;
 779                                 }
 780                                 if (put_user(addr, rp))
 781                                         return -EFAULT;
 782                         }
 783                 }
 784         }
 785 
 786         /*
 787          * Now run through the relocation entries.
 788          * We've got to be careful here as C++ produces relocatable zero
 789          * entries in the constructor and destructor tables which are then
 790          * tested for being not zero (which will always occur unless we're
 791          * based from address zero).  This causes an endless loop as __start
 792          * is at zero.  The solution used is to not relocate zero addresses.
 793          * This has the negative side effect of not allowing a global data
 794          * reference to be statically initialised to _stext (I've moved
 795          * __start to address 4 so that is okay).
 796          */
 797         if (rev > OLD_FLAT_VERSION) {
 798                 for (i = 0; i < relocs; i++) {
 799                         u32 addr, relval;
 800                         __be32 tmp;
 801 
 802                         /*
 803                          * Get the address of the pointer to be
 804                          * relocated (of course, the address has to be
 805                          * relocated first).
 806                          */
 807                         if (get_user(tmp, reloc + i))
 808                                 return -EFAULT;
 809                         relval = ntohl(tmp);
 810                         addr = flat_get_relocate_addr(relval);
 811                         rp = (u32 __user *)calc_reloc(addr, libinfo, id, 1);
 812                         if (rp == (u32 __user *)RELOC_FAILED) {
 813                                 ret = -ENOEXEC;
 814                                 goto err;
 815                         }
 816 
 817                         /* Get the pointer's value.  */
 818                         ret = flat_get_addr_from_rp(rp, relval, flags, &addr);
 819                         if (unlikely(ret))
 820                                 goto err;
 821 
 822                         if (addr != 0) {
 823                                 /*
 824                                  * Do the relocation.  PIC relocs in the data section are
 825                                  * already in target order
 826                                  */
 827                                 if ((flags & FLAT_FLAG_GOTPIC) == 0) {
 828                                         /*
 829                                          * Meh, the same value can have a different
 830                                          * byte order based on a flag..
 831                                          */
 832                                         addr = ntohl((__force __be32)addr);
 833                                 }
 834                                 addr = calc_reloc(addr, libinfo, id, 0);
 835                                 if (addr == RELOC_FAILED) {
 836                                         ret = -ENOEXEC;
 837                                         goto err;
 838                                 }
 839 
 840                                 /* Write back the relocated pointer.  */
 841                                 ret = flat_put_addr_at_rp(rp, addr, relval);
 842                                 if (unlikely(ret))
 843                                         goto err;
 844                         }
 845                 }
 846 #ifdef CONFIG_BINFMT_FLAT_OLD
 847         } else {
 848                 for (i = 0; i < relocs; i++) {
 849                         __be32 relval;
 850                         if (get_user(relval, reloc + i))
 851                                 return -EFAULT;
 852                         old_reloc(ntohl(relval));
 853                 }
 854 #endif /* CONFIG_BINFMT_FLAT_OLD */
 855         }
 856 
 857         flush_icache_range(start_code, end_code);
 858 
 859         /* zero the BSS,  BRK and stack areas */
 860         if (clear_user((void __user *)(datapos + data_len), bss_len +
 861                        (memp + memp_size - stack_len -          /* end brk */
 862                        libinfo->lib_list[id].start_brk) +       /* start brk */
 863                        stack_len))
 864                 return -EFAULT;
 865 
 866         return 0;
 867 err:
 868         return ret;
 869 }
 870 
 871 
 872 /****************************************************************************/
 873 #ifdef CONFIG_BINFMT_SHARED_FLAT
 874 
 875 /*
 876  * Load a shared library into memory.  The library gets its own data
 877  * segment (including bss) but not argv/argc/environ.
 878  */
 879 
 880 static int load_flat_shared_library(int id, struct lib_info *libs)
 881 {
 882         /*
 883          * This is a fake bprm struct; only the members "buf", "file" and
 884          * "filename" are actually used.
 885          */
 886         struct linux_binprm bprm;
 887         int res;
 888         char buf[16];
 889         loff_t pos = 0;
 890 
 891         memset(&bprm, 0, sizeof(bprm));
 892 
 893         /* Create the file name */
 894         sprintf(buf, "/lib/lib%d.so", id);
 895 
 896         /* Open the file up */
 897         bprm.filename = buf;
 898         bprm.file = open_exec(bprm.filename);
 899         res = PTR_ERR(bprm.file);
 900         if (IS_ERR(bprm.file))
 901                 return res;
 902 
 903         res = kernel_read(bprm.file, bprm.buf, BINPRM_BUF_SIZE, &pos);
 904 
 905         if (res >= 0)
 906                 res = load_flat_file(&bprm, libs, id, NULL);
 907 
 908         allow_write_access(bprm.file);
 909         fput(bprm.file);
 910 
 911         return res;
 912 }
 913 
 914 #endif /* CONFIG_BINFMT_SHARED_FLAT */
 915 /****************************************************************************/
 916 
 917 /*
 918  * These are the functions used to load flat style executables and shared
 919  * libraries.  There is no binary dependent code anywhere else.
 920  */
 921 
 922 static int load_flat_binary(struct linux_binprm *bprm)
 923 {
 924         struct lib_info libinfo;
 925         struct pt_regs *regs = current_pt_regs();
 926         unsigned long stack_len = 0;
 927         unsigned long start_addr;
 928         int res;
 929         int i, j;
 930 
 931         memset(&libinfo, 0, sizeof(libinfo));
 932 
 933         /*
 934          * We have to add the size of our arguments to our stack size
 935          * otherwise it's too easy for users to create stack overflows
 936          * by passing in a huge argument list.  And yes,  we have to be
 937          * pedantic and include space for the argv/envp array as it may have
 938          * a lot of entries.
 939          */
 940 #ifndef CONFIG_MMU
 941         stack_len += PAGE_SIZE * MAX_ARG_PAGES - bprm->p; /* the strings */
 942 #endif
 943         stack_len += (bprm->argc + 1) * sizeof(char *);   /* the argv array */
 944         stack_len += (bprm->envc + 1) * sizeof(char *);   /* the envp array */
 945         stack_len = ALIGN(stack_len, FLAT_STACK_ALIGN);
 946 
 947         res = load_flat_file(bprm, &libinfo, 0, &stack_len);
 948         if (res < 0)
 949                 return res;
 950 
 951         /* Update data segment pointers for all libraries */
 952         for (i = 0; i < MAX_SHARED_LIBS; i++) {
 953                 if (!libinfo.lib_list[i].loaded)
 954                         continue;
 955                 for (j = 0; j < MAX_SHARED_LIBS; j++) {
 956                         unsigned long val = libinfo.lib_list[j].loaded ?
 957                                 libinfo.lib_list[j].start_data : UNLOADED_LIB;
 958                         unsigned long __user *p = (unsigned long __user *)
 959                                 libinfo.lib_list[i].start_data;
 960                         p -= j + 1;
 961                         if (put_user(val, p))
 962                                 return -EFAULT;
 963                 }
 964         }
 965 
 966         install_exec_creds(bprm);
 967 
 968         set_binfmt(&flat_format);
 969 
 970 #ifdef CONFIG_MMU
 971         res = setup_arg_pages(bprm, STACK_TOP, EXSTACK_DEFAULT);
 972         if (!res)
 973                 res = create_flat_tables(bprm, bprm->p);
 974 #else
 975         /* Stash our initial stack pointer into the mm structure */
 976         current->mm->start_stack =
 977                 ((current->mm->context.end_brk + stack_len + 3) & ~3) - 4;
 978         pr_debug("sp=%lx\n", current->mm->start_stack);
 979 
 980         /* copy the arg pages onto the stack */
 981         res = transfer_args_to_stack(bprm, &current->mm->start_stack);
 982         if (!res)
 983                 res = create_flat_tables(bprm, current->mm->start_stack);
 984 #endif
 985         if (res)
 986                 return res;
 987 
 988         /* Fake some return addresses to ensure the call chain will
 989          * initialise library in order for us.  We are required to call
 990          * lib 1 first, then 2, ... and finally the main program (id 0).
 991          */
 992         start_addr = libinfo.lib_list[0].entry;
 993 
 994 #ifdef CONFIG_BINFMT_SHARED_FLAT
 995         for (i = MAX_SHARED_LIBS-1; i > 0; i--) {
 996                 if (libinfo.lib_list[i].loaded) {
 997                         /* Push previos first to call address */
 998                         unsigned long __user *sp;
 999                         current->mm->start_stack -= sizeof(unsigned long);
1000                         sp = (unsigned long __user *)current->mm->start_stack;
1001                         __put_user(start_addr, sp);
1002                         start_addr = libinfo.lib_list[i].entry;
1003                 }
1004         }
1005 #endif
1006 
1007 #ifdef FLAT_PLAT_INIT
1008         FLAT_PLAT_INIT(regs);
1009 #endif
1010 
1011         finalize_exec(bprm);
1012         pr_debug("start_thread(regs=0x%p, entry=0x%lx, start_stack=0x%lx)\n",
1013                  regs, start_addr, current->mm->start_stack);
1014         start_thread(regs, start_addr, current->mm->start_stack);
1015 
1016         return 0;
1017 }
1018 
1019 /****************************************************************************/
1020 
1021 static int __init init_flat_binfmt(void)
1022 {
1023         register_binfmt(&flat_format);
1024         return 0;
1025 }
1026 core_initcall(init_flat_binfmt);
1027 
1028 /****************************************************************************/
/* [<][>][^][v][top][bottom][index][help] */
root/fs/binfmt_flat.c

DEFINITIONS
