usr.sbin/crunch/crunchide/exec_elf32.c

   1 /*
   2  * Copyright (c) 1997 Christopher G. Demetriou.  All rights reserved.
   3  *
   4  * Redistribution and use in source and binary forms, with or without
   5  * modification, are permitted provided that the following conditions
   6  * are met:
   7  * 1. Redistributions of source code must retain the above copyright
   8  *    notice, this list of conditions and the following disclaimer.
   9  * 2. Redistributions in binary form must reproduce the above copyright
  10  *    notice, this list of conditions and the following disclaimer in the
  11  *    documentation and/or other materials provided with the distribution.
  12  * 3. All advertising materials mentioning features or use of this software
  13  *    must display the following acknowledgement:
  14  *      This product includes software developed by Christopher G. Demetriou
  15  *      for the NetBSD Project.
  16  * 4. The name of the author may not be used to endorse or promote products
  17  *    derived from this software without specific prior written permission
  18  *
  19  * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR
  20  * IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
  21  * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED.
  22  * IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT,
  23  * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT
  24  * NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
  25  * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
  26  * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
  27  * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF
  28  * THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
  29  */
  30
  31 #include <sys/cdefs.h>
  32 #ifndef lint
  33 #if 0
  34 __RCSID("$NetBSD: exec_elf32.c,v 1.4 1997/08/12 06:07:24 mikel Exp $");
  35 #endif
  36 #endif
  37 __FBSDID("$FreeBSD$");
  38
  39 #ifndef ELFSIZE
  40 #define ELFSIZE         32
  41 #endif
  42
  43 #include <sys/types.h>
  44 #include <sys/endian.h>
  45 #include <sys/stat.h>
  46
  47 #include <errno.h>
  48 #include <stdio.h>
  49 #include <stdlib.h>
  50 #include <string.h>
  51 #include <unistd.h>
  52
  53 #include "extern.h"
  54
  55 #if (defined(NLIST_ELF32) && (ELFSIZE == 32)) || \
  56     (defined(NLIST_ELF64) && (ELFSIZE == 64))
  57
  58 #define __ELF_WORD_SIZE ELFSIZE
  59 #if (ELFSIZE == 32)
  60 #include <sys/elf32.h>
  61 #define xewtoh(x)       ((data == ELFDATA2MSB) ? be32toh(x) : le32toh(x))
  62 #define htoxew(x)       ((data == ELFDATA2MSB) ? htobe32(x) : htole32(x))
  63 #elif (ELFSIZE == 64)
  64 #include <sys/elf64.h>
  65 #define xewtoh(x)       ((data == ELFDATA2MSB) ? be64toh(x) : le64toh(x))
  66 #define htoxew(x)       ((data == ELFDATA2MSB) ? htobe64(x) : htole64(x))
  67 #endif
  68 #include <sys/elf_generic.h>
  69
  70 #define CONCAT(x,y)     __CONCAT(x,y)
  71 #define ELFNAME(x)      CONCAT(elf,CONCAT(ELFSIZE,CONCAT(_,x)))
  72 #define ELFNAME2(x,y)   CONCAT(x,CONCAT(_elf,CONCAT(ELFSIZE,CONCAT(_,y))))
  73 #define ELFNAMEEND(x)   CONCAT(x,CONCAT(_elf,ELFSIZE))
  74 #define ELFDEFNNAME(x)  CONCAT(ELF,CONCAT(ELFSIZE,CONCAT(_,x)))
  75
  76 #define xe16toh(x)      ((data == ELFDATA2MSB) ? be16toh(x) : le16toh(x))
  77 #define xe32toh(x)      ((data == ELFDATA2MSB) ? be32toh(x) : le32toh(x))
  78 #define htoxe32(x)      ((data == ELFDATA2MSB) ? htobe32(x) : htole32(x))
  79
  80 struct listelem {
  81         struct listelem *next;
  82         void *mem;
  83         off_t file;
  84         size_t size;
  85 };
  86
  87 static ssize_t
  88 xreadatoff(int fd, void *buf, off_t off, size_t size, const char *fn)
  89 {
  90         ssize_t rv;
  91
  92         if (lseek(fd, off, SEEK_SET) != off) {
  93                 perror(fn);
  94                 return -1;
  95         }
  96         if ((rv = read(fd, buf, size)) != size) {
  97                 fprintf(stderr, "%s: read error: %s\n", fn,
  98                     rv == -1 ? strerror(errno) : "short read");
  99                 return -1;
 100         }
 101         return size;
 102 }
 103
 104 static ssize_t
 105 xwriteatoff(int fd, void *buf, off_t off, size_t size, const char *fn)
 106 {
 107         ssize_t rv;
 108
 109         if (lseek(fd, off, SEEK_SET) != off) {
 110                 perror(fn);
 111                 return -1;
 112         }
 113         if ((rv = write(fd, buf, size)) != size) {
 114                 fprintf(stderr, "%s: write error: %s\n", fn,
 115                     rv == -1 ? strerror(errno) : "short write");
 116                 return -1;
 117         }
 118         return size;
 119 }
 120
 121 static void *
 122 xmalloc(size_t size, const char *fn, const char *use)
 123 {
 124         void *rv;
 125
 126         rv = malloc(size);
 127         if (rv == NULL)
 128                 fprintf(stderr, "%s: out of memory (allocating for %s)\n",
 129                     fn, use);
 130         return (rv);
 131 }
 132
 133 int
 134 ELFNAMEEND(check)(int fd, const char *fn)
 135 {
 136         Elf_Ehdr eh;
 137         struct stat sb;
 138         unsigned char data;
 139
 140         /*
 141          * Check the header to maek sure it's an ELF file (of the
 142          * appropriate size).
 143          */
 144         if (fstat(fd, &sb) == -1)
 145                 return 0;
 146         if (sb.st_size < sizeof eh)
 147                 return 0;
 148         if (read(fd, &eh, sizeof eh) != sizeof eh)
 149                 return 0;
 150
 151         if (IS_ELF(eh) == 0)
 152                 return 0;
 153
 154         data = eh.e_ident[EI_DATA];
 155
 156         switch (xe16toh(eh.e_machine)) {
 157         case EM_386: break;
 158         case EM_ALPHA: break;
 159 #ifndef EM_ARM
 160 #define EM_ARM          40
 161 #endif
 162         case EM_ARM: break;
 163 #ifndef EM_MIPS
 164 #define EM_MIPS         8
 165 #endif
 166 #ifndef EM_MIPS_RS4_BE          /* same as EM_MIPS_RS3_LE */
 167 #define EM_MIPS_RS4_BE  10
 168 #endif
 169         case EM_MIPS: break;
 170         case /* EM_MIPS_RS3_LE */ EM_MIPS_RS4_BE: break;
 171 #ifndef EM_IA_64
 172 #define EM_IA_64        50
 173 #endif
 174         case EM_IA_64: break;
 175 #ifndef EM_PPC
 176 #define EM_PPC          20
 177 #endif
 178         case EM_PPC: break;
 179 #ifndef EM_SPARCV9
 180 #define EM_SPARCV9      43
 181 #endif
 182         case EM_SPARCV9: break;
 183 #ifndef EM_X86_64
 184 #define EM_X86_64       62
 185 #endif
 186         case EM_X86_64: break;
 187 /*        ELFDEFNNAME(MACHDEP_ID_CASES) */
 188
 189         default:
 190                 return 0;
 191         }
 192
 193         return 1;
 194 }
 195
 196 int
 197 ELFNAMEEND(hide)(int fd, const char *fn)
 198 {
 199         Elf_Ehdr ehdr;
 200         Elf_Shdr *shdrp = NULL, *symtabshdr, *strtabshdr;
 201         Elf_Sym *symtabp = NULL;
 202         char *strtabp = NULL;
 203         Elf_Size *symfwmap = NULL, *symrvmap = NULL, nsyms, nlocalsyms, ewi;
 204         struct listelem *relalist = NULL, *rellist = NULL, *tmpl;
 205         ssize_t shdrsize;
 206         int rv, i, weird;
 207         unsigned char data;
 208
 209         rv = 0;
 210         if (xreadatoff(fd, &ehdr, 0, sizeof ehdr, fn) != sizeof ehdr)
 211                 goto bad;
 212
 213         data = ehdr.e_ident[EI_DATA];
 214
 215         shdrsize = xe16toh(ehdr.e_shnum) * xe16toh(ehdr.e_shentsize);
 216         if ((shdrp = xmalloc(shdrsize, fn, "section header table")) == NULL)
 217                 goto bad;
 218         if (xreadatoff(fd, shdrp, xewtoh(ehdr.e_shoff), shdrsize, fn) !=
 219             shdrsize)
 220                 goto bad;
 221
 222         symtabshdr = strtabshdr = NULL;
 223         weird = 0;
 224         for (i = 0; i < xe16toh(ehdr.e_shnum); i++) {
 225                 switch (xe32toh(shdrp[i].sh_type)) {
 226                 case SHT_SYMTAB:
 227                         if (symtabshdr != NULL)
 228                                 weird = 1;
 229                         symtabshdr = &shdrp[i];
 230                         strtabshdr = &shdrp[xe32toh(shdrp[i].sh_link)];
 231                         break;
 232                 case SHT_RELA:
 233                         tmpl = xmalloc(sizeof *tmpl, fn, "rela list element");
 234                         if (tmpl == NULL)
 235                                 goto bad;
 236                         tmpl->mem = NULL;
 237                         tmpl->file = xewtoh(shdrp[i].sh_offset);
 238                         tmpl->size = xewtoh(shdrp[i].sh_size);
 239                         tmpl->next = relalist;
 240                         relalist = tmpl;
 241                         break;
 242                 case SHT_REL:
 243                         tmpl = xmalloc(sizeof *tmpl, fn, "rel list element");
 244                         if (tmpl == NULL)
 245                                 goto bad;
 246                         tmpl->mem = NULL;
 247                         tmpl->file = xewtoh(shdrp[i].sh_offset);
 248                         tmpl->size = xewtoh(shdrp[i].sh_size);
 249                         tmpl->next = rellist;
 250                         rellist = tmpl;
 251                         break;
 252                 }
 253         }
 254         if (symtabshdr == NULL)
 255                 goto out;
 256         if (strtabshdr == NULL)
 257                 weird = 1;
 258         if (weird) {
 259                 fprintf(stderr, "%s: weird executable (unsupported)\n", fn);
 260                 goto bad;
 261         }
 262
 263         /*
 264          * load up everything we need
 265          */
 266
 267         /* symbol table */
 268         if ((symtabp = xmalloc(xewtoh(symtabshdr->sh_size), fn, "symbol table"))
 269             == NULL)
 270                 goto bad;
 271         if (xreadatoff(fd, symtabp, xewtoh(symtabshdr->sh_offset),
 272             xewtoh(symtabshdr->sh_size), fn) != xewtoh(symtabshdr->sh_size))
 273                 goto bad;
 274
 275         /* string table */
 276         if ((strtabp = xmalloc(xewtoh(strtabshdr->sh_size), fn, "string table"))
 277             == NULL)
 278                 goto bad;
 279         if (xreadatoff(fd, strtabp, xewtoh(strtabshdr->sh_offset),
 280             xewtoh(strtabshdr->sh_size), fn) != xewtoh(strtabshdr->sh_size))
 281                 goto bad;
 282
 283         /* any rela tables */
 284         for (tmpl = relalist; tmpl != NULL; tmpl = tmpl->next) {
 285                 if ((tmpl->mem = xmalloc(tmpl->size, fn, "rela table"))
 286                     == NULL)
 287                         goto bad;
 288                 if (xreadatoff(fd, tmpl->mem, tmpl->file,
 289                     tmpl->size, fn) != tmpl->size)
 290                         goto bad;
 291         }
 292
 293         /* any rel tables */
 294         for (tmpl = rellist; tmpl != NULL; tmpl = tmpl->next) {
 295                 if ((tmpl->mem = xmalloc(tmpl->size, fn, "rel table"))
 296                     == NULL)
 297                         goto bad;
 298                 if (xreadatoff(fd, tmpl->mem, tmpl->file,
 299                     tmpl->size, fn) != tmpl->size)
 300                         goto bad;
 301         }
 302
 303         /* Prepare data structures for symbol movement. */
 304         nsyms = xewtoh(symtabshdr->sh_size) / xewtoh(symtabshdr->sh_entsize);
 305         nlocalsyms = xe32toh(symtabshdr->sh_info);
 306         if ((symfwmap = xmalloc(nsyms * sizeof (Elf_Size), fn,
 307             "symbol forward mapping table")) == NULL)
 308                 goto bad;
 309         if ((symrvmap = xmalloc(nsyms * sizeof (Elf_Size), fn,
 310             "symbol reverse mapping table")) == NULL)
 311                 goto bad;
 312
 313         /* init location -> symbol # table */
 314         for (ewi = 0; ewi < nsyms; ewi++)
 315                 symrvmap[ewi] = ewi;
 316
 317         /* move symbols, making them local */
 318         for (ewi = nlocalsyms; ewi < nsyms; ewi++) {
 319                 Elf_Sym *sp, symswap;
 320                 Elf_Size mapswap;
 321
 322                 sp = &symtabp[ewi];
 323
 324                 /* if it's on our keep list, don't move it */
 325                 if (in_keep_list(strtabp + xe32toh(sp->st_name)))
 326                         continue;
 327
 328                 /* if it's an undefined symbol, keep it */
 329                 if (xe16toh(sp->st_shndx) == SHN_UNDEF)
 330                         continue;
 331
 332                 /* adjust the symbol so that it's local */
 333                 sp->st_info =
 334                     ELF_ST_INFO(STB_LOCAL, sp->st_info);
 335 /*                  (STB_LOCAL << 4) | ELF_SYM_TYPE(sp->st_info); *//* XXX */
 336
 337                 /*
 338                  * move the symbol to its new location
 339                  */
 340
 341                 /* note that symbols in those locations have been swapped */
 342                 mapswap = symrvmap[ewi];
 343                 symrvmap[ewi] = symrvmap[nlocalsyms];
 344                 symrvmap[nlocalsyms] = mapswap;
 345
 346                 /* and swap the symbols */
 347                 symswap = *sp;
 348                 *sp = symtabp[nlocalsyms];
 349                 symtabp[nlocalsyms] = symswap;
 350
 351                 nlocalsyms++;                   /* note new local sym */
 352         }
 353         symtabshdr->sh_info = htoxe32(nlocalsyms);
 354
 355         /* set up symbol # -> location mapping table */
 356         for (ewi = 0; ewi < nsyms; ewi++)
 357                 symfwmap[symrvmap[ewi]] = ewi;
 358
 359         /* any rela tables */
 360         for (tmpl = relalist; tmpl != NULL; tmpl = tmpl->next) {
 361                 Elf_Rela *relap = tmpl->mem;
 362
 363                 for (ewi = 0; ewi < tmpl->size / sizeof(*relap); ewi++) {
 364                         relap[ewi].r_info = htoxew(ELF_R_INFO(
 365                             symfwmap[ELF_R_SYM(xewtoh(relap[ewi].r_info))],
 366                             ELF_R_TYPE(xewtoh(relap[ewi].r_info))
 367                         ));
 368                 }
 369         }
 370
 371         /* any rel tables */
 372         for (tmpl = rellist; tmpl != NULL; tmpl = tmpl->next) {
 373                 Elf_Rel *relp = tmpl->mem;
 374
 375                 for (ewi = 0; ewi < tmpl->size / sizeof *relp; ewi++) {
 376                         relp[ewi].r_info = htoxew(ELF_R_INFO(
 377                             symfwmap[ELF_R_SYM(xewtoh(relp[ewi].r_info))],
 378                             ELF_R_TYPE(xewtoh(relp[ewi].r_info))
 379                         ));
 380                 }
 381         }
 382
 383         /*
 384          * write new tables to the file
 385          */
 386         if (xwriteatoff(fd, shdrp, xewtoh(ehdr.e_shoff), shdrsize, fn) !=
 387             shdrsize)
 388                 goto bad;
 389         if (xwriteatoff(fd, symtabp, xewtoh(symtabshdr->sh_offset),
 390             xewtoh(symtabshdr->sh_size), fn) != xewtoh(symtabshdr->sh_size))
 391                 goto bad;
 392         for (tmpl = relalist; tmpl != NULL; tmpl = tmpl->next) {
 393                 if (xwriteatoff(fd, tmpl->mem, tmpl->file,
 394                     tmpl->size, fn) != tmpl->size)
 395                         goto bad;
 396         }
 397         for (tmpl = rellist; tmpl != NULL; tmpl = tmpl->next) {
 398                 if (xwriteatoff(fd, tmpl->mem, tmpl->file,
 399                     tmpl->size, fn) != tmpl->size)
 400                         goto bad;
 401         }
 402
 403 out:
 404         if (shdrp != NULL)
 405                 free(shdrp);
 406         if (symtabp != NULL)
 407                 free(symtabp);
 408         if (strtabp != NULL)
 409                 free(strtabp);
 410         if (symfwmap != NULL)
 411                 free(symfwmap);
 412         if (symrvmap != NULL)
 413                 free(symrvmap);
 414         while ((tmpl = relalist) != NULL) {
 415                 relalist = tmpl->next;
 416                 if (tmpl->mem != NULL)
 417                         free(tmpl->mem);
 418                 free(tmpl);
 419         }
 420         while ((tmpl = rellist) != NULL) {
 421                 rellist = tmpl->next;
 422                 if (tmpl->mem != NULL)
 423                         free(tmpl->mem);
 424                 free(tmpl);
 425         }
 426         return (rv);
 427
 428 bad:
 429         rv = 1;
 430         goto out;
 431 }
 432
 433 #endif /* include this size of ELF */