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 */ 434