fs/binfmt_flat.c

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