| 1 | /* $NetBSD: linux_exec_elf32.c,v 1.93 2015/06/11 02:54:00 matt 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 1.93 2015/06/11 02:54:00 matt 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 | #include <sys/cprng.h> |
| 58 | |
| 59 | #include <sys/mman.h> |
| 60 | #include <sys/syscallargs.h> |
| 61 | |
| 62 | #include <sys/cpu.h> |
| 63 | #include <machine/reg.h> |
| 64 | |
| 65 | #include <compat/linux/common/linux_types.h> |
| 66 | #include <compat/linux/common/linux_signal.h> |
| 67 | #include <compat/linux/common/linux_util.h> |
| 68 | #include <compat/linux/common/linux_exec.h> |
| 69 | #include <compat/linux/common/linux_machdep.h> |
| 70 | #include <compat/linux/common/linux_ipc.h> |
| 71 | #include <compat/linux/common/linux_sem.h> |
| 72 | |
| 73 | #include <compat/linux/linux_syscallargs.h> |
| 74 | #include <compat/linux/linux_syscall.h> |
| 75 | |
| 76 | #ifdef DEBUG_LINUX |
| 77 | #define DPRINTF(a) uprintf a |
| 78 | #else |
| 79 | #define DPRINTF(a) |
| 80 | #endif |
| 81 | |
| 82 | #ifdef LINUX_ATEXIT_SIGNATURE |
| 83 | /* |
| 84 | * On the PowerPC, statically linked Linux binaries are not recognized |
| 85 | * by linux_signature nor by linux_gcc_signature. Fortunately, thoses |
| 86 | * binaries features a __libc_atexit ELF section. We therefore assume we |
| 87 | * have a Linux binary if we find this section. |
| 88 | */ |
| 89 | int |
| 90 | ELFNAME2(linux,atexit_signature)( |
| 91 | struct lwp *l, |
| 92 | struct exec_package *epp, |
| 93 | Elf_Ehdr *eh) |
| 94 | { |
| 95 | Elf_Shdr *sh; |
| 96 | size_t shsize; |
| 97 | u_int shstrndx; |
| 98 | size_t i; |
| 99 | static const char signature[] = "__libc_atexit" ; |
| 100 | const size_t sigsz = sizeof(signature); |
| 101 | char tbuf[sizeof(signature)]; |
| 102 | int error; |
| 103 | |
| 104 | /* Load the section header table. */ |
| 105 | shsize = eh->e_shnum * sizeof(Elf_Shdr); |
| 106 | sh = (Elf_Shdr *) malloc(shsize, M_TEMP, M_WAITOK); |
| 107 | error = exec_read_from(l, epp->ep_vp, eh->e_shoff, sh, shsize); |
| 108 | if (error) |
| 109 | goto out; |
| 110 | |
| 111 | /* Now let's find the string table. If it does not exist, give up. */ |
| 112 | shstrndx = eh->e_shstrndx; |
| 113 | if (shstrndx == SHN_UNDEF || shstrndx >= eh->e_shnum) { |
| 114 | error = ENOEXEC; |
| 115 | goto out; |
| 116 | } |
| 117 | |
| 118 | /* Check if any section has the name we're looking for. */ |
| 119 | const off_t stroff = sh[shstrndx].sh_offset; |
| 120 | for (i = 0; i < eh->e_shnum; i++) { |
| 121 | Elf_Shdr *s = &sh[i]; |
| 122 | |
| 123 | if (s->sh_name + sigsz > sh[shstrndx].sh_size) |
| 124 | continue; |
| 125 | |
| 126 | error = exec_read_from(l, epp->ep_vp, stroff + s->sh_name, tbuf, |
| 127 | sigsz); |
| 128 | if (error) |
| 129 | goto out; |
| 130 | if (!memcmp(tbuf, signature, sigsz)) { |
| 131 | DPRINTF(("linux_atexit_sig=%s\n" , tbuf)); |
| 132 | error = 0; |
| 133 | goto out; |
| 134 | } |
| 135 | } |
| 136 | error = ENOEXEC; |
| 137 | |
| 138 | out: |
| 139 | free(sh, M_TEMP); |
| 140 | return (error); |
| 141 | } |
| 142 | #endif |
| 143 | |
| 144 | #ifdef LINUX_GCC_SIGNATURE |
| 145 | /* |
| 146 | * Take advantage of the fact that all the linux binaries are compiled |
| 147 | * with gcc, and gcc sticks in the comment field a signature. Note that |
| 148 | * on SVR4 binaries, the gcc signature will follow the OS name signature, |
| 149 | * that will not be a problem. We don't bother to read in the string table, |
| 150 | * but we check all the progbits headers. |
| 151 | * |
| 152 | * XXX This only works in the i386. On the alpha (at least) |
| 153 | * XXX we have the same gcc signature which incorrectly identifies |
| 154 | * XXX NetBSD binaries as Linux. |
| 155 | */ |
| 156 | int |
| 157 | ELFNAME2(linux,gcc_signature)( |
| 158 | struct lwp *l, |
| 159 | struct exec_package *epp, |
| 160 | Elf_Ehdr *eh) |
| 161 | { |
| 162 | size_t shsize; |
| 163 | size_t i; |
| 164 | static const char signature[] = "\0GCC: (GNU) " ; |
| 165 | char tbuf[sizeof(signature) - 1]; |
| 166 | Elf_Shdr *sh; |
| 167 | int error; |
| 168 | |
| 169 | shsize = eh->e_shnum * sizeof(Elf_Shdr); |
| 170 | sh = (Elf_Shdr *) malloc(shsize, M_TEMP, M_WAITOK); |
| 171 | error = exec_read_from(l, epp->ep_vp, eh->e_shoff, sh, shsize); |
| 172 | if (error) |
| 173 | goto out; |
| 174 | |
| 175 | for (i = 0; i < eh->e_shnum; i++) { |
| 176 | Elf_Shdr *s = &sh[i]; |
| 177 | |
| 178 | /* |
| 179 | * Identify candidates for the comment header; |
| 180 | * Header cannot have a load address, or flags and |
| 181 | * it must be large enough. |
| 182 | */ |
| 183 | if (s->sh_type != SHT_PROGBITS || |
| 184 | s->sh_addr != 0 || |
| 185 | s->sh_flags != 0 || |
| 186 | s->sh_size < sizeof(signature) - 1) |
| 187 | continue; |
| 188 | |
| 189 | error = exec_read_from(l, epp->ep_vp, s->sh_offset, tbuf, |
| 190 | sizeof(signature) - 1); |
| 191 | if (error) |
| 192 | continue; |
| 193 | |
| 194 | /* |
| 195 | * error is 0, if the signatures match we are done. |
| 196 | */ |
| 197 | DPRINTF(("linux_gcc_sig: sig=%s\n" , tbuf)); |
| 198 | if (!memcmp(tbuf, signature, sizeof(signature) - 1)) { |
| 199 | error = 0; |
| 200 | goto out; |
| 201 | } |
| 202 | } |
| 203 | error = ENOEXEC; |
| 204 | |
| 205 | out: |
| 206 | free(sh, M_TEMP); |
| 207 | return (error); |
| 208 | } |
| 209 | #endif |
| 210 | |
| 211 | #ifdef LINUX_DEBUGLINK_SIGNATURE |
| 212 | /* |
| 213 | * Look for a .gnu_debuglink, specific to x86_64 interpreter |
| 214 | */ |
| 215 | int |
| 216 | ELFNAME2(linux,debuglink_signature)(struct lwp *l, struct exec_package *epp, Elf_Ehdr *eh) |
| 217 | { |
| 218 | Elf_Shdr *sh; |
| 219 | size_t shsize; |
| 220 | u_int shstrndx; |
| 221 | size_t i; |
| 222 | static const char signature[] = ".gnu_debuglink" ; |
| 223 | const size_t sigsz = sizeof(signature); |
| 224 | char tbuf[sizeof(signature)]; |
| 225 | int error; |
| 226 | |
| 227 | /* Load the section header table. */ |
| 228 | shsize = eh->e_shnum * sizeof(Elf_Shdr); |
| 229 | sh = (Elf_Shdr *) malloc(shsize, M_TEMP, M_WAITOK); |
| 230 | error = exec_read_from(l, epp->ep_vp, eh->e_shoff, sh, shsize); |
| 231 | if (error) |
| 232 | goto out; |
| 233 | |
| 234 | /* Now let's find the string table. If it does not exist, give up. */ |
| 235 | shstrndx = eh->e_shstrndx; |
| 236 | if (shstrndx == SHN_UNDEF || shstrndx >= eh->e_shnum) { |
| 237 | error = ENOEXEC; |
| 238 | goto out; |
| 239 | } |
| 240 | |
| 241 | /* Check if any section has the name we're looking for. */ |
| 242 | const off_t stroff = sh[shstrndx].sh_offset; |
| 243 | for (i = 0; i < eh->e_shnum; i++) { |
| 244 | Elf_Shdr *s = &sh[i]; |
| 245 | |
| 246 | if (s->sh_name + sigsz > sh[shstrndx].sh_size) |
| 247 | continue; |
| 248 | |
| 249 | error = exec_read_from(l, epp->ep_vp, stroff + s->sh_name, tbuf, |
| 250 | sigsz); |
| 251 | if (error) |
| 252 | goto out; |
| 253 | if (!memcmp(tbuf, signature, sigsz)) { |
| 254 | DPRINTF(("linux_debuglink_sig=%s\n" , tbuf)); |
| 255 | error = 0; |
| 256 | goto out; |
| 257 | } |
| 258 | } |
| 259 | error = ENOEXEC; |
| 260 | |
| 261 | out: |
| 262 | free(sh, M_TEMP); |
| 263 | return (error); |
| 264 | } |
| 265 | #endif |
| 266 | |
| 267 | int |
| 268 | ELFNAME2(linux,signature)(struct lwp *l, struct exec_package *epp, Elf_Ehdr *eh, char *itp) |
| 269 | { |
| 270 | size_t i; |
| 271 | Elf_Phdr *ph; |
| 272 | size_t phsize; |
| 273 | int error; |
| 274 | static const char linux[] = "Linux" ; |
| 275 | |
| 276 | if (eh->e_ident[EI_OSABI] == 3 || |
| 277 | memcmp(&eh->e_ident[EI_ABIVERSION], linux, sizeof(linux)) == 0) |
| 278 | return 0; |
| 279 | |
| 280 | phsize = eh->e_phnum * sizeof(Elf_Phdr); |
| 281 | ph = (Elf_Phdr *)malloc(phsize, M_TEMP, M_WAITOK); |
| 282 | error = exec_read_from(l, epp->ep_vp, eh->e_phoff, ph, phsize); |
| 283 | if (error) |
| 284 | goto out; |
| 285 | |
| 286 | for (i = 0; i < eh->e_phnum; i++) { |
| 287 | Elf_Phdr *ephp = &ph[i]; |
| 288 | Elf_Nhdr *np; |
| 289 | u_int32_t *abi; |
| 290 | |
| 291 | if (ephp->p_type != PT_NOTE || |
| 292 | ephp->p_filesz > 1024 || |
| 293 | ephp->p_filesz < sizeof(Elf_Nhdr) + 20) |
| 294 | continue; |
| 295 | |
| 296 | np = (Elf_Nhdr *)malloc(ephp->p_filesz, M_TEMP, M_WAITOK); |
| 297 | error = exec_read_from(l, epp->ep_vp, ephp->p_offset, np, |
| 298 | ephp->p_filesz); |
| 299 | if (error) |
| 300 | goto next; |
| 301 | |
| 302 | if (np->n_type != ELF_NOTE_TYPE_ABI_TAG || |
| 303 | np->n_namesz != ELF_NOTE_ABI_NAMESZ || |
| 304 | np->n_descsz != ELF_NOTE_ABI_DESCSZ || |
| 305 | memcmp((void *)(np + 1), ELF_NOTE_ABI_NAME, |
| 306 | ELF_NOTE_ABI_NAMESZ)) |
| 307 | goto next; |
| 308 | |
| 309 | /* Make sure the OS is Linux. */ |
| 310 | abi = (u_int32_t *)((char *)np + sizeof(Elf_Nhdr) + |
| 311 | np->n_namesz); |
| 312 | if (abi[0] == ELF_NOTE_ABI_OS_LINUX) |
| 313 | error = 0; |
| 314 | else |
| 315 | error = ENOEXEC; |
| 316 | free(np, M_TEMP); |
| 317 | goto out; |
| 318 | |
| 319 | next: |
| 320 | free(np, M_TEMP); |
| 321 | continue; |
| 322 | } |
| 323 | |
| 324 | /* Check for certain interpreter names. */ |
| 325 | if (itp) { |
| 326 | if (!strncmp(itp, "/lib/ld-linux" , 13) || |
| 327 | #if (ELFSIZE == 64) |
| 328 | !strncmp(itp, "/lib64/ld-linux" , 15) || |
| 329 | #endif |
| 330 | !strncmp(itp, "/lib/ld.so." , 11)) |
| 331 | error = 0; |
| 332 | else |
| 333 | error = ENOEXEC; |
| 334 | goto out; |
| 335 | } |
| 336 | |
| 337 | error = ENOEXEC; |
| 338 | out: |
| 339 | free(ph, M_TEMP); |
| 340 | return (error); |
| 341 | } |
| 342 | |
| 343 | int |
| 344 | ELFNAME2(linux,probe)(struct lwp *l, struct exec_package *epp, void *eh, |
| 345 | char *itp, vaddr_t *pos) |
| 346 | { |
| 347 | int error; |
| 348 | |
| 349 | if (((error = ELFNAME2(linux,signature)(l, epp, eh, itp)) != 0) && |
| 350 | #ifdef LINUX_GCC_SIGNATURE |
| 351 | ((error = ELFNAME2(linux,gcc_signature)(l, epp, eh)) != 0) && |
| 352 | #endif |
| 353 | #ifdef LINUX_ATEXIT_SIGNATURE |
| 354 | ((error = ELFNAME2(linux,atexit_signature)(l, epp, eh)) != 0) && |
| 355 | #endif |
| 356 | #ifdef LINUX_DEBUGLINK_SIGNATURE |
| 357 | ((error = ELFNAME2(linux,debuglink_signature)(l, epp, eh)) != 0) && |
| 358 | #endif |
| 359 | 1) { |
| 360 | DPRINTF(("linux_probe: returning %d\n" , error)); |
| 361 | return error; |
| 362 | } |
| 363 | |
| 364 | if (itp) { |
| 365 | if ((error = emul_find_interp(l, epp, itp))) |
| 366 | return (error); |
| 367 | } |
| 368 | epp->ep_flags |= EXEC_FORCEAUX; |
| 369 | DPRINTF(("linux_probe: returning 0\n" )); |
| 370 | return 0; |
| 371 | } |
| 372 | |
| 373 | #ifndef LINUX_MACHDEP_ELF_COPYARGS |
| 374 | /* |
| 375 | * Copy arguments onto the stack in the normal way, but add some |
| 376 | * extra information in case of dynamic binding. |
| 377 | */ |
| 378 | int |
| 379 | ELFNAME2(linux,copyargs)(struct lwp *l, struct exec_package *pack, |
| 380 | struct ps_strings *arginfo, char **stackp, void *argp) |
| 381 | { |
| 382 | size_t len; |
| 383 | AuxInfo ai[LINUX_ELF_AUX_ENTRIES], *a; |
| 384 | struct elf_args *ap; |
| 385 | int error; |
| 386 | struct vattr *vap; |
| 387 | uint32_t randbytes[4]; |
| 388 | |
| 389 | if ((error = copyargs(l, pack, arginfo, stackp, argp)) != 0) |
| 390 | return error; |
| 391 | |
| 392 | a = ai; |
| 393 | |
| 394 | memset(ai, 0, sizeof(ai)); |
| 395 | |
| 396 | /* |
| 397 | * Push extra arguments used by glibc on the stack. |
| 398 | */ |
| 399 | |
| 400 | a->a_type = AT_PAGESZ; |
| 401 | a->a_v = PAGE_SIZE; |
| 402 | a++; |
| 403 | |
| 404 | if ((ap = (struct elf_args *)pack->ep_emul_arg)) { |
| 405 | |
| 406 | a->a_type = AT_PHDR; |
| 407 | a->a_v = ap->arg_phaddr; |
| 408 | a++; |
| 409 | |
| 410 | a->a_type = AT_PHENT; |
| 411 | a->a_v = ap->arg_phentsize; |
| 412 | a++; |
| 413 | |
| 414 | a->a_type = AT_PHNUM; |
| 415 | a->a_v = ap->arg_phnum; |
| 416 | a++; |
| 417 | |
| 418 | a->a_type = AT_BASE; |
| 419 | a->a_v = ap->arg_interp; |
| 420 | a++; |
| 421 | |
| 422 | a->a_type = AT_FLAGS; |
| 423 | a->a_v = 0; |
| 424 | a++; |
| 425 | |
| 426 | a->a_type = AT_ENTRY; |
| 427 | a->a_v = ap->arg_entry; |
| 428 | a++; |
| 429 | |
| 430 | exec_free_emul_arg(pack); |
| 431 | } |
| 432 | |
| 433 | /* Linux-specific items */ |
| 434 | a->a_type = LINUX_AT_CLKTCK; |
| 435 | a->a_v = hz; |
| 436 | a++; |
| 437 | |
| 438 | vap = pack->ep_vap; |
| 439 | |
| 440 | a->a_type = LINUX_AT_UID; |
| 441 | a->a_v = kauth_cred_getuid(l->l_cred); |
| 442 | a++; |
| 443 | |
| 444 | a->a_type = LINUX_AT_EUID; |
| 445 | if (vap->va_mode & S_ISUID) |
| 446 | a->a_v = vap->va_uid; |
| 447 | else |
| 448 | a->a_v = kauth_cred_geteuid(l->l_cred); |
| 449 | a++; |
| 450 | |
| 451 | a->a_type = LINUX_AT_GID; |
| 452 | a->a_v = kauth_cred_getgid(l->l_cred); |
| 453 | a++; |
| 454 | |
| 455 | a->a_type = LINUX_AT_EGID; |
| 456 | if (vap->va_mode & S_ISGID) |
| 457 | a->a_v = vap->va_gid; |
| 458 | else |
| 459 | a->a_v = kauth_cred_getegid(l->l_cred); |
| 460 | a++; |
| 461 | |
| 462 | a->a_type = LINUX_AT_RANDOM; |
| 463 | a->a_v = (Elf_Addr)(uintptr_t)*stackp; |
| 464 | a++; |
| 465 | |
| 466 | a->a_type = AT_NULL; |
| 467 | a->a_v = 0; |
| 468 | a++; |
| 469 | |
| 470 | randbytes[0] = cprng_strong32(); |
| 471 | randbytes[1] = cprng_strong32(); |
| 472 | randbytes[2] = cprng_strong32(); |
| 473 | randbytes[3] = cprng_strong32(); |
| 474 | |
| 475 | len = sizeof(randbytes); |
| 476 | if ((error = copyout(randbytes, *stackp, len)) != 0) |
| 477 | return error; |
| 478 | *stackp += len; |
| 479 | |
| 480 | len = (a - ai) * sizeof(AuxInfo); |
| 481 | KASSERT(len <= LINUX_ELF_AUX_ENTRIES * sizeof(AuxInfo)); |
| 482 | if ((error = copyout(ai, *stackp, len)) != 0) |
| 483 | return error; |
| 484 | *stackp += len; |
| 485 | |
| 486 | return 0; |
| 487 | } |
| 488 | #endif /* !LINUX_MACHDEP_ELF_COPYARGS */ |
| 489 | |