linux_exec_elf32.c revision 1.81.8.1
1 /* $NetBSD: linux_exec_elf32.c,v 1.81.8.1 2009/01/19 13:17:31 skrll Exp $ */ 2 3 /*- 4 * Copyright (c) 1995, 1998, 2000, 2001 The NetBSD Foundation, Inc. 5 * All rights reserved. 6 * 7 * This code is derived from software contributed to The NetBSD Foundation 8 * by Christos Zoulas, Frank van der Linden, Eric Haszlakiewicz and 9 * Emmanuel Dreyfus. 10 * 11 * Redistribution and use in source and binary forms, with or without 12 * modification, are permitted provided that the following conditions 13 * are met: 14 * 1. Redistributions of source code must retain the above copyright 15 * notice, this list of conditions and the following disclaimer. 16 * 2. Redistributions in binary form must reproduce the above copyright 17 * notice, this list of conditions and the following disclaimer in the 18 * documentation and/or other materials provided with the distribution. 19 * 20 * THIS SOFTWARE IS PROVIDED BY THE NETBSD FOUNDATION, INC. AND CONTRIBUTORS 21 * ``AS IS'' AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED 22 * TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR 23 * PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE FOUNDATION OR CONTRIBUTORS 24 * BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR 25 * CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF 26 * SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS 27 * INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN 28 * CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) 29 * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE 30 * POSSIBILITY OF SUCH DAMAGE. 31 */ 32 33 /* 34 * based on exec_aout.c, sunos_exec.c and svr4_exec.c 35 */ 36 37 #include <sys/cdefs.h> 38 __KERNEL_RCSID(0, "$NetBSD: linux_exec_elf32.c,v 1.81.8.1 2009/01/19 13:17:31 skrll Exp $"); 39 40 #ifndef ELFSIZE 41 /* XXX should die */ 42 #define ELFSIZE 32 43 #endif 44 45 #include <sys/param.h> 46 #include <sys/systm.h> 47 #include <sys/kernel.h> 48 #include <sys/proc.h> 49 #include <sys/malloc.h> 50 #include <sys/namei.h> 51 #include <sys/vnode.h> 52 #include <sys/mount.h> 53 #include <sys/exec.h> 54 #include <sys/exec_elf.h> 55 #include <sys/stat.h> 56 #include <sys/kauth.h> 57 58 #include <sys/mman.h> 59 #include <sys/syscallargs.h> 60 61 #include <sys/cpu.h> 62 #include <machine/reg.h> 63 64 #include <compat/linux/common/linux_types.h> 65 #include <compat/linux/common/linux_signal.h> 66 #include <compat/linux/common/linux_util.h> 67 #include <compat/linux/common/linux_exec.h> 68 #include <compat/linux/common/linux_machdep.h> 69 #include <compat/linux/common/linux_ipc.h> 70 #include <compat/linux/common/linux_sem.h> 71 72 #include <compat/linux/linux_syscallargs.h> 73 #include <compat/linux/linux_syscall.h> 74 75 #ifdef DEBUG_LINUX 76 #define DPRINTF(a) uprintf a 77 #else 78 #define DPRINTF(a) 79 #endif 80 81 #ifdef LINUX_ATEXIT_SIGNATURE 82 /* 83 * On the PowerPC, statically linked Linux binaries are not recognized 84 * by linux_signature nor by linux_gcc_signature. Fortunately, thoses 85 * binaries features a __libc_atexit ELF section. We therefore assume we 86 * have a Linux binary if we find this section. 87 */ 88 int 89 ELFNAME2(linux,atexit_signature)(l, epp, eh) 90 struct lwp *l; 91 struct exec_package *epp; 92 Elf_Ehdr *eh; 93 { 94 size_t shsize; 95 int strndx; 96 size_t i; 97 static const char signature[] = "__libc_atexit"; 98 char *strtable = NULL; 99 Elf_Shdr *sh; 100 101 int error; 102 103 /* 104 * load the section header table 105 */ 106 shsize = eh->e_shnum * sizeof(Elf_Shdr); 107 sh = (Elf_Shdr *) malloc(shsize, M_TEMP, M_WAITOK); 108 error = exec_read_from(l, epp->ep_vp, eh->e_shoff, sh, shsize); 109 if (error) 110 goto out; 111 112 /* 113 * Now let's find the string table. If it does not exists, give up. 114 */ 115 strndx = (int)(eh->e_shstrndx); 116 if (strndx == SHN_UNDEF) { 117 error = ENOEXEC; 118 goto out; 119 } 120 121 /* 122 * strndx is the index in section header table of the string table 123 * section get the whole string table in strtable, and then we get access to the names 124 * s->sh_name is the offset of the section name in strtable. 125 */ 126 strtable = malloc(sh[strndx].sh_size, M_TEMP, M_WAITOK); 127 error = exec_read_from(l, epp->ep_vp, sh[strndx].sh_offset, strtable, 128 sh[strndx].sh_size); 129 if (error) 130 goto out; 131 132 for (i = 0; i < eh->e_shnum; i++) { 133 Elf_Shdr *s = &sh[i]; 134 if (!memcmp((void*)(&(strtable[s->sh_name])), signature, 135 sizeof(signature))) { 136 DPRINTF(("linux_atexit_sig=%s\n", 137 &(strtable[s->sh_name]))); 138 error = 0; 139 goto out; 140 } 141 } 142 error = ENOEXEC; 143 144 out: 145 free(sh, M_TEMP); 146 if (strtable) 147 free(strtable, M_TEMP); 148 return (error); 149 } 150 #endif 151 152 #ifdef LINUX_GCC_SIGNATURE 153 /* 154 * Take advantage of the fact that all the linux binaries are compiled 155 * with gcc, and gcc sticks in the comment field a signature. Note that 156 * on SVR4 binaries, the gcc signature will follow the OS name signature, 157 * that will not be a problem. We don't bother to read in the string table, 158 * but we check all the progbits headers. 159 * 160 * XXX This only works in the i386. On the alpha (at least) 161 * XXX we have the same gcc signature which incorrectly identifies 162 * XXX NetBSD binaries as Linux. 163 */ 164 int 165 ELFNAME2(linux,gcc_signature)(l, epp, eh) 166 struct lwp *l; 167 struct exec_package *epp; 168 Elf_Ehdr *eh; 169 { 170 size_t shsize; 171 size_t i; 172 static const char signature[] = "\0GCC: (GNU) "; 173 char tbuf[sizeof(signature) - 1]; 174 Elf_Shdr *sh; 175 int error; 176 177 shsize = eh->e_shnum * sizeof(Elf_Shdr); 178 sh = (Elf_Shdr *) malloc(shsize, M_TEMP, M_WAITOK); 179 error = exec_read_from(l, epp->ep_vp, eh->e_shoff, sh, shsize); 180 if (error) 181 goto out; 182 183 for (i = 0; i < eh->e_shnum; i++) { 184 Elf_Shdr *s = &sh[i]; 185 186 /* 187 * Identify candidates for the comment header; 188 * Header cannot have a load address, or flags and 189 * it must be large enough. 190 */ 191 if (s->sh_type != SHT_PROGBITS || 192 s->sh_addr != 0 || 193 s->sh_flags != 0 || 194 s->sh_size < sizeof(signature) - 1) 195 continue; 196 197 error = exec_read_from(l, epp->ep_vp, s->sh_offset, tbuf, 198 sizeof(signature) - 1); 199 if (error) 200 continue; 201 202 /* 203 * error is 0, if the signatures match we are done. 204 */ 205 DPRINTF(("linux_gcc_sig: sig=%s\n", tbuf)); 206 if (!memcmp(tbuf, signature, sizeof(signature) - 1)) { 207 error = 0; 208 goto out; 209 } 210 } 211 error = ENOEXEC; 212 213 out: 214 free(sh, M_TEMP); 215 return (error); 216 } 217 #endif 218 219 #ifdef LINUX_DEBUGLINK_SIGNATURE 220 /* 221 * Look for a .gnu_debuglink, specific to x86_64 interpeter 222 */ 223 int 224 ELFNAME2(linux,debuglink_signature)(l, epp, eh) 225 struct lwp *l; 226 struct exec_package *epp; 227 Elf_Ehdr *eh; 228 { 229 size_t shsize; 230 int strndx; 231 size_t i; 232 static const char signature[] = ".gnu_debuglink"; 233 char *strtable = NULL; 234 Elf_Shdr *sh; 235 236 int error; 237 238 /* 239 * load the section header table 240 */ 241 shsize = eh->e_shnum * sizeof(Elf_Shdr); 242 sh = (Elf_Shdr *) malloc(shsize, M_TEMP, M_WAITOK); 243 error = exec_read_from(l, epp->ep_vp, eh->e_shoff, sh, shsize); 244 if (error) 245 goto out; 246 247 /* 248 * Now let's find the string table. If it does not exists, give up. 249 */ 250 strndx = (int)(eh->e_shstrndx); 251 if (strndx == SHN_UNDEF) { 252 error = ENOEXEC; 253 goto out; 254 } 255 256 /* 257 * strndx is the index in section header table of the string table 258 * section get the whole string table in strtable, and then we get access to the names 259 * s->sh_name is the offset of the section name in strtable. 260 */ 261 strtable = malloc(sh[strndx].sh_size, M_TEMP, M_WAITOK); 262 error = exec_read_from(l, epp->ep_vp, sh[strndx].sh_offset, strtable, 263 sh[strndx].sh_size); 264 if (error) 265 goto out; 266 267 for (i = 0; i < eh->e_shnum; i++) { 268 Elf_Shdr *s = &sh[i]; 269 270 if (!memcmp((void*)(&(strtable[s->sh_name])), signature, 271 sizeof(signature))) { 272 DPRINTF(("linux_debuglink_sig=%s\n", 273 &(strtable[s->sh_name]))); 274 error = 0; 275 goto out; 276 } 277 } 278 error = ENOEXEC; 279 280 out: 281 free(sh, M_TEMP); 282 if (strtable) 283 free(strtable, M_TEMP); 284 return (error); 285 } 286 #endif 287 288 int 289 ELFNAME2(linux,signature)(l, epp, eh, itp) 290 struct lwp *l; 291 struct exec_package *epp; 292 Elf_Ehdr *eh; 293 char *itp; 294 { 295 size_t i; 296 Elf_Phdr *ph; 297 size_t phsize; 298 int error; 299 static const char linux[] = "Linux"; 300 301 if (eh->e_ident[EI_OSABI] == 3 || 302 memcmp(&eh->e_ident[EI_ABIVERSION], linux, sizeof(linux)) == 0) 303 return 0; 304 305 phsize = eh->e_phnum * sizeof(Elf_Phdr); 306 ph = (Elf_Phdr *)malloc(phsize, M_TEMP, M_WAITOK); 307 error = exec_read_from(l, epp->ep_vp, eh->e_phoff, ph, phsize); 308 if (error) 309 goto out; 310 311 for (i = 0; i < eh->e_phnum; i++) { 312 Elf_Phdr *ephp = &ph[i]; 313 Elf_Nhdr *np; 314 u_int32_t *abi; 315 316 if (ephp->p_type != PT_NOTE || 317 ephp->p_filesz > 1024 || 318 ephp->p_filesz < sizeof(Elf_Nhdr) + 20) 319 continue; 320 321 np = (Elf_Nhdr *)malloc(ephp->p_filesz, M_TEMP, M_WAITOK); 322 error = exec_read_from(l, epp->ep_vp, ephp->p_offset, np, 323 ephp->p_filesz); 324 if (error) 325 goto next; 326 327 if (np->n_type != ELF_NOTE_TYPE_ABI_TAG || 328 np->n_namesz != ELF_NOTE_ABI_NAMESZ || 329 np->n_descsz != ELF_NOTE_ABI_DESCSZ || 330 memcmp((void *)(np + 1), ELF_NOTE_ABI_NAME, 331 ELF_NOTE_ABI_NAMESZ)) 332 goto next; 333 334 /* Make sure the OS is Linux. */ 335 abi = (u_int32_t *)((char *)np + sizeof(Elf_Nhdr) + 336 np->n_namesz); 337 if (abi[0] == ELF_NOTE_ABI_OS_LINUX) 338 error = 0; 339 else 340 error = ENOEXEC; 341 free(np, M_TEMP); 342 goto out; 343 344 next: 345 free(np, M_TEMP); 346 continue; 347 } 348 349 /* Check for certain intepreter names. */ 350 if (itp) { 351 if (!strncmp(itp, "/lib/ld-linux", 13) || 352 #if (ELFSIZE == 64) 353 !strncmp(itp, "/lib64/ld-linux", 15) || 354 #endif 355 !strncmp(itp, "/lib/ld.so.", 11)) 356 error = 0; 357 else 358 error = ENOEXEC; 359 goto out; 360 } 361 362 error = ENOEXEC; 363 out: 364 free(ph, M_TEMP); 365 return (error); 366 } 367 368 int 369 ELFNAME2(linux,probe)(struct lwp *l, struct exec_package *epp, void *eh, 370 char *itp, vaddr_t *pos) 371 { 372 int error; 373 374 if (((error = ELFNAME2(linux,signature)(l, epp, eh, itp)) != 0) && 375 #ifdef LINUX_GCC_SIGNATURE 376 ((error = ELFNAME2(linux,gcc_signature)(l, epp, eh)) != 0) && 377 #endif 378 #ifdef LINUX_ATEXIT_SIGNATURE 379 ((error = ELFNAME2(linux,atexit_signature)(l, epp, eh)) != 0) && 380 #endif 381 #ifdef LINUX_DEBUGLINK_SIGNATURE 382 ((error = ELFNAME2(linux,debuglink_signature)(l, epp, eh)) != 0) && 383 #endif 384 1) { 385 DPRINTF(("linux_probe: returning %d\n", error)); 386 return error; 387 } 388 389 if (itp) { 390 if ((error = emul_find_interp(l, epp, itp))) 391 return (error); 392 } 393 DPRINTF(("linux_probe: returning 0\n")); 394 return 0; 395 } 396 397 #ifndef LINUX_MACHDEP_ELF_COPYARGS 398 /* 399 * Copy arguments onto the stack in the normal way, but add some 400 * extra information in case of dynamic binding. 401 */ 402 int 403 ELFNAME2(linux,copyargs)(struct lwp *l, struct exec_package *pack, 404 struct ps_strings *arginfo, char **stackp, void *argp) 405 { 406 size_t len; 407 AuxInfo ai[LINUX_ELF_AUX_ENTRIES], *a; 408 struct elf_args *ap; 409 int error; 410 struct vattr *vap; 411 412 if ((error = copyargs(l, pack, arginfo, stackp, argp)) != 0) 413 return error; 414 415 a = ai; 416 417 /* 418 * Push extra arguments used by glibc on the stack. 419 */ 420 421 a->a_type = AT_PAGESZ; 422 a->a_v = PAGE_SIZE; 423 a++; 424 425 if ((ap = (struct elf_args *)pack->ep_emul_arg)) { 426 427 a->a_type = AT_PHDR; 428 a->a_v = ap->arg_phaddr; 429 a++; 430 431 a->a_type = AT_PHENT; 432 a->a_v = ap->arg_phentsize; 433 a++; 434 435 a->a_type = AT_PHNUM; 436 a->a_v = ap->arg_phnum; 437 a++; 438 439 a->a_type = AT_BASE; 440 a->a_v = ap->arg_interp; 441 a++; 442 443 a->a_type = AT_FLAGS; 444 a->a_v = 0; 445 a++; 446 447 a->a_type = AT_ENTRY; 448 a->a_v = ap->arg_entry; 449 a++; 450 451 free(pack->ep_emul_arg, M_TEMP); 452 pack->ep_emul_arg = NULL; 453 } 454 455 /* Linux-specific items */ 456 a->a_type = LINUX_AT_CLKTCK; 457 a->a_v = hz; 458 a++; 459 460 vap = pack->ep_vap; 461 462 a->a_type = LINUX_AT_UID; 463 a->a_v = kauth_cred_getuid(l->l_cred); 464 a++; 465 466 a->a_type = LINUX_AT_EUID; 467 if (vap->va_mode & S_ISUID) 468 a->a_v = vap->va_uid; 469 else 470 a->a_v = kauth_cred_geteuid(l->l_cred); 471 a++; 472 473 a->a_type = LINUX_AT_GID; 474 a->a_v = kauth_cred_getgid(l->l_cred); 475 a++; 476 477 a->a_type = LINUX_AT_EGID; 478 if (vap->va_mode & S_ISGID) 479 a->a_v = vap->va_gid; 480 else 481 a->a_v = kauth_cred_getegid(l->l_cred); 482 a++; 483 484 a->a_type = AT_NULL; 485 a->a_v = 0; 486 a++; 487 488 len = (a - ai) * sizeof(AuxInfo); 489 if ((error = copyout(ai, *stackp, len)) != 0) 490 return error; 491 *stackp += len; 492 493 return 0; 494 } 495 #endif /* !LINUX_MACHDEP_ELF_COPYARGS */ 496
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