fs/binfmt_flat.c

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