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_IA_64 160 #define EM_IA_64 50 161 #endif 162 case EM_IA_64: break; 163 #ifndef EM_PPC 164 #define EM_PPC 20 165 #endif 166 case EM_PPC: break; 167 #ifndef EM_SPARCV9 168 #define EM_SPARCV9 43 169 #endif 170 case EM_SPARCV9: break; 171 #ifndef EM_X86_64 172 #define EM_X86_64 62 173 #endif 174 case EM_X86_64: break; 175 /* ELFDEFNNAME(MACHDEP_ID_CASES) */ 176 177 default: 178 return 0; 179 } 180 181 return 1; 182 } 183 184 int 185 ELFNAMEEND(hide)(int fd, const char *fn) 186 { 187 Elf_Ehdr ehdr; 188 Elf_Shdr *shdrp = NULL, *symtabshdr, *strtabshdr; 189 Elf_Sym *symtabp = NULL; 190 char *strtabp = NULL; 191 Elf_Word *symfwmap = NULL, *symrvmap = NULL, nsyms, nlocalsyms, ewi; 192 struct listelem *relalist = NULL, *rellist = NULL, *tmpl; 193 ssize_t shdrsize; 194 int rv, i, weird; 195 unsigned char data; 196 197 rv = 0; 198 if (xreadatoff(fd, &ehdr, 0, sizeof ehdr, fn) != sizeof ehdr) 199 goto bad; 200 201 data = ehdr.e_ident[EI_DATA]; 202 203 shdrsize = xe16toh(ehdr.e_shnum) * xe16toh(ehdr.e_shentsize); 204 if ((shdrp = xmalloc(shdrsize, fn, "section header table")) == NULL) 205 goto bad; 206 if (xreadatoff(fd, shdrp, xewtoh(ehdr.e_shoff), shdrsize, fn) != 207 shdrsize) 208 goto bad; 209 210 symtabshdr = strtabshdr = NULL; 211 weird = 0; 212 for (i = 0; i < xe16toh(ehdr.e_shnum); i++) { 213 switch (xe32toh(shdrp[i].sh_type)) { 214 case SHT_SYMTAB: 215 if (symtabshdr != NULL) 216 weird = 1; 217 symtabshdr = &shdrp[i]; 218 strtabshdr = &shdrp[xe32toh(shdrp[i].sh_link)]; 219 break; 220 case SHT_RELA: 221 tmpl = xmalloc(sizeof *tmpl, fn, "rela list element"); 222 if (tmpl == NULL) 223 goto bad; 224 tmpl->mem = NULL; 225 tmpl->file = xewtoh(shdrp[i].sh_offset); 226 tmpl->size = xewtoh(shdrp[i].sh_size); 227 tmpl->next = relalist; 228 relalist = tmpl; 229 break; 230 case SHT_REL: 231 tmpl = xmalloc(sizeof *tmpl, fn, "rel list element"); 232 if (tmpl == NULL) 233 goto bad; 234 tmpl->mem = NULL; 235 tmpl->file = xewtoh(shdrp[i].sh_offset); 236 tmpl->size = xewtoh(shdrp[i].sh_size); 237 tmpl->next = rellist; 238 rellist = tmpl; 239 break; 240 } 241 } 242 if (symtabshdr == NULL) 243 goto out; 244 if (strtabshdr == NULL) 245 weird = 1; 246 if (weird) { 247 fprintf(stderr, "%s: weird executable (unsupported)\n", fn); 248 goto bad; 249 } 250 251 /* 252 * load up everything we need 253 */ 254 255 /* symbol table */ 256 if ((symtabp = xmalloc(xewtoh(symtabshdr->sh_size), fn, "symbol table")) 257 == NULL) 258 goto bad; 259 if (xreadatoff(fd, symtabp, xewtoh(symtabshdr->sh_offset), 260 xewtoh(symtabshdr->sh_size), fn) != xewtoh(symtabshdr->sh_size)) 261 goto bad; 262 263 /* string table */ 264 if ((strtabp = xmalloc(xewtoh(strtabshdr->sh_size), fn, "string table")) 265 == NULL) 266 goto bad; 267 if (xreadatoff(fd, strtabp, xewtoh(strtabshdr->sh_offset), 268 xewtoh(strtabshdr->sh_size), fn) != xewtoh(strtabshdr->sh_size)) 269 goto bad; 270 271 /* any rela tables */ 272 for (tmpl = relalist; tmpl != NULL; tmpl = tmpl->next) { 273 if ((tmpl->mem = xmalloc(tmpl->size, fn, "rela table")) 274 == NULL) 275 goto bad; 276 if (xreadatoff(fd, tmpl->mem, tmpl->file, 277 tmpl->size, fn) != tmpl->size) 278 goto bad; 279 } 280 281 /* any rel tables */ 282 for (tmpl = rellist; tmpl != NULL; tmpl = tmpl->next) { 283 if ((tmpl->mem = xmalloc(tmpl->size, fn, "rel table")) 284 == NULL) 285 goto bad; 286 if (xreadatoff(fd, tmpl->mem, tmpl->file, 287 tmpl->size, fn) != tmpl->size) 288 goto bad; 289 } 290 291 /* Prepare data structures for symbol movement. */ 292 nsyms = xewtoh(symtabshdr->sh_size) / xewtoh(symtabshdr->sh_entsize); 293 nlocalsyms = xe32toh(symtabshdr->sh_info); 294 if ((symfwmap = xmalloc(nsyms * sizeof (Elf_Word), fn, 295 "symbol forward mapping table")) == NULL) 296 goto bad; 297 if ((symrvmap = xmalloc(nsyms * sizeof (Elf_Word), fn, 298 "symbol reverse mapping table")) == NULL) 299 goto bad; 300 301 /* init location -> symbol # table */ 302 for (ewi = 0; ewi < nsyms; ewi++) 303 symrvmap[ewi] = ewi; 304 305 /* move symbols, making them local */ 306 for (ewi = nlocalsyms; ewi < nsyms; ewi++) { 307 Elf_Sym *sp, symswap; 308 Elf_Word mapswap; 309 310 sp = &symtabp[ewi]; 311 312 /* if it's on our keep list, don't move it */ 313 if (in_keep_list(strtabp + xe32toh(sp->st_name))) 314 continue; 315 316 /* if it's an undefined symbol, keep it */ 317 if (xe16toh(sp->st_shndx) == SHN_UNDEF) 318 continue; 319 320 /* adjust the symbol so that it's local */ 321 sp->st_info = 322 ELF_ST_INFO(STB_LOCAL, sp->st_info); 323 /* (STB_LOCAL << 4) | ELF_SYM_TYPE(sp->st_info); *//* XXX */ 324 325 /* 326 * move the symbol to its new location 327 */ 328 329 /* note that symbols in those locations have been swapped */ 330 mapswap = symrvmap[ewi]; 331 symrvmap[ewi] = symrvmap[nlocalsyms]; 332 symrvmap[nlocalsyms] = mapswap; 333 334 /* and swap the symbols */ 335 symswap = *sp; 336 *sp = symtabp[nlocalsyms]; 337 symtabp[nlocalsyms] = symswap; 338 339 nlocalsyms++; /* note new local sym */ 340 } 341 symtabshdr->sh_info = htoxe32(nlocalsyms); 342 343 /* set up symbol # -> location mapping table */ 344 for (ewi = 0; ewi < nsyms; ewi++) 345 symfwmap[symrvmap[ewi]] = ewi; 346 347 /* any rela tables */ 348 for (tmpl = relalist; tmpl != NULL; tmpl = tmpl->next) { 349 Elf_Rela *relap = tmpl->mem; 350 351 for (ewi = 0; ewi < tmpl->size / sizeof(*relap); ewi++) { 352 relap[ewi].r_info = htoxew(ELF_R_INFO( 353 symfwmap[ELF_R_SYM(xewtoh(relap[ewi].r_info))], 354 ELF_R_TYPE(xewtoh(relap[ewi].r_info)) 355 )); 356 } 357 } 358 359 /* any rel tables */ 360 for (tmpl = rellist; tmpl != NULL; tmpl = tmpl->next) { 361 Elf_Rel *relp = tmpl->mem; 362 363 for (ewi = 0; ewi < tmpl->size / sizeof *relp; ewi++) { 364 relp[ewi].r_info = htoxew(ELF_R_INFO( 365 symfwmap[ELF_R_SYM(xewtoh(relp[ewi].r_info))], 366 ELF_R_TYPE(xewtoh(relp[ewi].r_info)) 367 )); 368 } 369 } 370 371 /* 372 * write new tables to the file 373 */ 374 if (xwriteatoff(fd, shdrp, xewtoh(ehdr.e_shoff), shdrsize, fn) != 375 shdrsize) 376 goto bad; 377 if (xwriteatoff(fd, symtabp, xewtoh(symtabshdr->sh_offset), 378 xewtoh(symtabshdr->sh_size), fn) != xewtoh(symtabshdr->sh_size)) 379 goto bad; 380 for (tmpl = relalist; tmpl != NULL; tmpl = tmpl->next) { 381 if (xwriteatoff(fd, tmpl->mem, tmpl->file, 382 tmpl->size, fn) != tmpl->size) 383 goto bad; 384 } 385 for (tmpl = rellist; tmpl != NULL; tmpl = tmpl->next) { 386 if (xwriteatoff(fd, tmpl->mem, tmpl->file, 387 tmpl->size, fn) != tmpl->size) 388 goto bad; 389 } 390 391 out: 392 if (shdrp != NULL) 393 free(shdrp); 394 if (symtabp != NULL) 395 free(symtabp); 396 if (strtabp != NULL) 397 free(strtabp); 398 if (symfwmap != NULL) 399 free(symfwmap); 400 if (symrvmap != NULL) 401 free(symrvmap); 402 while ((tmpl = relalist) != NULL) { 403 relalist = tmpl->next; 404 if (tmpl->mem != NULL) 405 free(tmpl->mem); 406 free(tmpl); 407 } 408 while ((tmpl = rellist) != NULL) { 409 rellist = tmpl->next; 410 if (tmpl->mem != NULL) 411 free(tmpl->mem); 412 free(tmpl); 413 } 414 return (rv); 415 416 bad: 417 rv = 1; 418 goto out; 419 } 420 421 #endif /* include this size of ELF */ 422