1 /* $NetBSD: linux_exec_elf32.c,v 1.70 2005/12/11 12:20:19 christos 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 * 3. All advertising materials mentioning features or use of this software 20 * must display the following acknowledgement: 21 * This product includes software developed by the NetBSD 22 * Foundation, Inc. and its contributors. 23 * 4. Neither the name of The NetBSD Foundation nor the names of its 24 * contributors may be used to endorse or promote products derived 25 * from this software without specific prior written permission. 26 * 27 * THIS SOFTWARE IS PROVIDED BY THE NETBSD FOUNDATION, INC. AND CONTRIBUTORS 28 * ``AS IS'' AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED 29 * TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR 30 * PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE FOUNDATION OR CONTRIBUTORS 31 * BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR 32 * CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF 33 * SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS 34 * INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN 35 * CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) 36 * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE 37 * POSSIBILITY OF SUCH DAMAGE. 38 */ 39 40 /* 41 * based on exec_aout.c, sunos_exec.c and svr4_exec.c 42 */ 43 44 #include <sys/cdefs.h> 45 __KERNEL_RCSID(0, "$NetBSD: linux_exec_elf32.c,v 1.70 2005/12/11 12:20:19 christos Exp $"); 46 47 #ifndef ELFSIZE 48 /* XXX should die */ 49 #define ELFSIZE 32 50 #endif 51 52 #include <sys/param.h> 53 #include <sys/systm.h> 54 #include <sys/kernel.h> 55 #include <sys/proc.h> 56 #include <sys/malloc.h> 57 #include <sys/namei.h> 58 #include <sys/vnode.h> 59 #include <sys/mount.h> 60 #include <sys/exec.h> 61 #include <sys/exec_elf.h> 62 #include <sys/stat.h> 63 64 #include <sys/mman.h> 65 #include <sys/sa.h> 66 #include <sys/syscallargs.h> 67 68 #include <machine/cpu.h> 69 #include <machine/reg.h> 70 71 #include <compat/linux/common/linux_types.h> 72 #include <compat/linux/common/linux_signal.h> 73 #include <compat/linux/common/linux_util.h> 74 #include <compat/linux/common/linux_exec.h> 75 #include <compat/linux/common/linux_machdep.h> 76 77 #include <compat/linux/linux_syscallargs.h> 78 #include <compat/linux/linux_syscall.h> 79 80 static int ELFNAME2(linux,signature) __P((struct lwp *, struct exec_package *, 81 Elf_Ehdr *, char *)); 82 #ifdef LINUX_GCC_SIGNATURE 83 static int ELFNAME2(linux,gcc_signature) __P((struct lwp *l, 84 struct exec_package *, Elf_Ehdr *)); 85 #endif 86 #ifdef LINUX_ATEXIT_SIGNATURE 87 static int ELFNAME2(linux,atexit_signature) __P((struct lwp *l, 88 struct exec_package *, Elf_Ehdr *)); 89 #endif 90 91 #ifdef DEBUG_LINUX 92 #define DPRINTF(a) uprintf a 93 #else 94 #define DPRINTF(a) 95 #endif 96 97 #ifdef LINUX_ATEXIT_SIGNATURE 98 /* 99 * On the PowerPC, statically linked Linux binaries are not recognized 100 * by linux_signature nor by linux_gcc_signature. Fortunately, thoses 101 * binaries features a __libc_atexit ELF section. We therefore assume we 102 * have a Linux binary if we find this section. 103 */ 104 static int 105 ELFNAME2(linux,atexit_signature)(l, epp, eh) 106 struct lwp *l; 107 struct exec_package *epp; 108 Elf_Ehdr *eh; 109 { 110 size_t shsize; 111 int strndx; 112 size_t i; 113 static const char signature[] = "__libc_atexit"; 114 char *strtable = NULL; 115 Elf_Shdr *sh; 116 117 int error; 118 119 /* 120 * load the section header table 121 */ 122 shsize = eh->e_shnum * sizeof(Elf_Shdr); 123 sh = (Elf_Shdr *) malloc(shsize, M_TEMP, M_WAITOK); 124 error = exec_read_from(l, epp->ep_vp, eh->e_shoff, sh, shsize); 125 if (error) 126 goto out; 127 128 /* 129 * Now let's find the string table. If it does not exists, give up. 130 */ 131 strndx = (int)(eh->e_shstrndx); 132 if (strndx == SHN_UNDEF) { 133 error = ENOEXEC; 134 goto out; 135 } 136 137 /* 138 * strndx is the index in section header table of the string table 139 * section get the whole string table in strtable, and then we get access to the names 140 * s->sh_name is the offset of the section name in strtable. 141 */ 142 strtable = malloc(sh[strndx].sh_size, M_TEMP, M_WAITOK); 143 error = exec_read_from(l, epp->ep_vp, sh[strndx].sh_offset, strtable, 144 sh[strndx].sh_size); 145 if (error) 146 goto out; 147 148 for (i = 0; i < eh->e_shnum; i++) { 149 Elf_Shdr *s = &sh[i]; 150 if (!memcmp((void*)(&(strtable[s->sh_name])), signature, 151 sizeof(signature))) { 152 DPRINTF(("linux_atexit_sig=%s\n", 153 &(strtable[s->sh_name]))); 154 error = 0; 155 goto out; 156 } 157 } 158 error = ENOEXEC; 159 160 out: 161 free(sh, M_TEMP); 162 if (strtable) 163 free(strtable, M_TEMP); 164 return (error); 165 } 166 #endif 167 168 #ifdef LINUX_GCC_SIGNATURE 169 /* 170 * Take advantage of the fact that all the linux binaries are compiled 171 * with gcc, and gcc sticks in the comment field a signature. Note that 172 * on SVR4 binaries, the gcc signature will follow the OS name signature, 173 * that will not be a problem. We don't bother to read in the string table, 174 * but we check all the progbits headers. 175 * 176 * XXX This only works in the i386. On the alpha (at least) 177 * XXX we have the same gcc signature which incorrectly identifies 178 * XXX NetBSD binaries as Linux. 179 */ 180 static int 181 ELFNAME2(linux,gcc_signature)(l, epp, eh) 182 struct lwp *l; 183 struct exec_package *epp; 184 Elf_Ehdr *eh; 185 { 186 size_t shsize; 187 size_t i; 188 static const char signature[] = "\0GCC: (GNU) "; 189 char tbuf[sizeof(signature) - 1]; 190 Elf_Shdr *sh; 191 int error; 192 193 shsize = eh->e_shnum * sizeof(Elf_Shdr); 194 sh = (Elf_Shdr *) malloc(shsize, M_TEMP, M_WAITOK); 195 error = exec_read_from(l, epp->ep_vp, eh->e_shoff, sh, shsize); 196 if (error) 197 goto out; 198 199 for (i = 0; i < eh->e_shnum; i++) { 200 Elf_Shdr *s = &sh[i]; 201 202 /* 203 * Identify candidates for the comment header; 204 * Header cannot have a load address, or flags and 205 * it must be large enough. 206 */ 207 if (s->sh_type != SHT_PROGBITS || 208 s->sh_addr != 0 || 209 s->sh_flags != 0 || 210 s->sh_size < sizeof(signature) - 1) 211 continue; 212 213 error = exec_read_from(l, epp->ep_vp, s->sh_offset, tbuf, 214 sizeof(signature) - 1); 215 if (error) 216 continue; 217 218 /* 219 * error is 0, if the signatures match we are done. 220 */ 221 DPRINTF(("linux_gcc_sig: sig=%s\n", tbuf)); 222 if (!memcmp(tbuf, signature, sizeof(signature) - 1)) { 223 error = 0; 224 goto out; 225 } 226 } 227 error = ENOEXEC; 228 229 out: 230 free(sh, M_TEMP); 231 return (error); 232 } 233 #endif 234 235 static int 236 ELFNAME2(linux,signature)(l, epp, eh, itp) 237 struct lwp *l; 238 struct exec_package *epp; 239 Elf_Ehdr *eh; 240 char *itp; 241 { 242 size_t i; 243 Elf_Phdr *ph; 244 size_t phsize; 245 int error; 246 static const char linux[] = "Linux"; 247 248 if (eh->e_ident[EI_OSABI] == 3 || 249 memcmp(&eh->e_ident[EI_ABIVERSION], linux, sizeof(linux)) == 0) 250 return 0; 251 252 phsize = eh->e_phnum * sizeof(Elf_Phdr); 253 ph = (Elf_Phdr *)malloc(phsize, M_TEMP, M_WAITOK); 254 error = exec_read_from(l, epp->ep_vp, eh->e_phoff, ph, phsize); 255 if (error) 256 goto out; 257 258 for (i = 0; i < eh->e_phnum; i++) { 259 Elf_Phdr *ephp = &ph[i]; 260 Elf_Nhdr *np; 261 u_int32_t *abi; 262 263 if (ephp->p_type != PT_NOTE || 264 ephp->p_filesz > 1024 || 265 ephp->p_filesz < sizeof(Elf_Nhdr) + 20) 266 continue; 267 268 np = (Elf_Nhdr *)malloc(ephp->p_filesz, M_TEMP, M_WAITOK); 269 error = exec_read_from(l, epp->ep_vp, ephp->p_offset, np, 270 ephp->p_filesz); 271 if (error) 272 goto next; 273 274 if (np->n_type != ELF_NOTE_TYPE_ABI_TAG || 275 np->n_namesz != ELF_NOTE_ABI_NAMESZ || 276 np->n_descsz != ELF_NOTE_ABI_DESCSZ || 277 memcmp((caddr_t)(np + 1), ELF_NOTE_ABI_NAME, 278 ELF_NOTE_ABI_NAMESZ)) 279 goto next; 280 281 /* Make sure the OS is Linux. */ 282 abi = (u_int32_t *)((caddr_t)np + sizeof(Elf_Nhdr) + 283 np->n_namesz); 284 if (abi[0] == ELF_NOTE_ABI_OS_LINUX) 285 error = 0; 286 else 287 error = ENOEXEC; 288 free(np, M_TEMP); 289 goto out; 290 291 next: 292 free(np, M_TEMP); 293 continue; 294 } 295 296 /* Check for certain intepreter names. */ 297 if (itp) { 298 if (!strncmp(itp, "/lib/ld-linux", 13) || 299 #if (ELFSIZE == 64) 300 !strncmp(itp, "/lib64/ld-linux", 15) || 301 #endif 302 !strncmp(itp, "/lib/ld.so.", 11)) 303 error = 0; 304 else 305 error = ENOEXEC; 306 goto out; 307 } 308 309 error = ENOEXEC; 310 out: 311 free(ph, M_TEMP); 312 return (error); 313 } 314 315 int 316 ELFNAME2(linux,probe)(l, epp, eh, itp, pos) 317 struct lwp *l; 318 struct exec_package *epp; 319 void *eh; 320 char *itp; 321 vaddr_t *pos; 322 { 323 int error; 324 325 if (((error = ELFNAME2(linux,signature)(l, epp, eh, itp)) != 0) && 326 #ifdef LINUX_GCC_SIGNATURE 327 ((error = ELFNAME2(linux,gcc_signature)(l, epp, eh)) != 0) && 328 #endif 329 #ifdef LINUX_ATEXIT_SIGNATURE 330 ((error = ELFNAME2(linux,atexit_signature)(l, epp, eh)) != 0) && 331 #endif 332 1) 333 return error; 334 335 if (itp) { 336 if ((error = emul_find_interp(l, epp->ep_esch->es_emul->e_path, 337 itp))) 338 return (error); 339 } 340 DPRINTF(("linux_probe: returning 0\n")); 341 return 0; 342 } 343 344 #ifndef LINUX_MACHDEP_ELF_COPYARGS 345 /* 346 * Copy arguments onto the stack in the normal way, but add some 347 * extra information in case of dynamic binding. 348 */ 349 int 350 ELFNAME2(linux,copyargs)(struct lwp *l, struct exec_package *pack, 351 struct ps_strings *arginfo, char **stackp, void *argp) 352 { 353 struct proc *p = l->l_proc; 354 size_t len; 355 AuxInfo ai[LINUX_ELF_AUX_ENTRIES], *a; 356 struct elf_args *ap; 357 int error; 358 struct vattr *vap; 359 360 if ((error = copyargs(l, pack, arginfo, stackp, argp)) != 0) 361 return error; 362 363 a = ai; 364 365 /* 366 * Push extra arguments used by glibc on the stack. 367 */ 368 369 a->a_type = AT_PAGESZ; 370 a->a_v = PAGE_SIZE; 371 a++; 372 373 if ((ap = (struct elf_args *)pack->ep_emul_arg)) { 374 375 a->a_type = AT_PHDR; 376 a->a_v = ap->arg_phaddr; 377 a++; 378 379 a->a_type = AT_PHENT; 380 a->a_v = ap->arg_phentsize; 381 a++; 382 383 a->a_type = AT_PHNUM; 384 a->a_v = ap->arg_phnum; 385 a++; 386 387 a->a_type = AT_BASE; 388 a->a_v = ap->arg_interp; 389 a++; 390 391 a->a_type = AT_FLAGS; 392 a->a_v = 0; 393 a++; 394 395 a->a_type = AT_ENTRY; 396 a->a_v = ap->arg_entry; 397 a++; 398 399 free(pack->ep_emul_arg, M_TEMP); 400 pack->ep_emul_arg = NULL; 401 } 402 403 /* Linux-specific items */ 404 a->a_type = LINUX_AT_CLKTCK; 405 a->a_v = hz; 406 a++; 407 408 vap = pack->ep_vap; 409 410 a->a_type = LINUX_AT_UID; 411 a->a_v = p->p_cred->p_ruid; 412 a++; 413 414 a->a_type = LINUX_AT_EUID; 415 if (vap->va_mode & S_ISUID) 416 a->a_v = vap->va_uid; 417 else 418 a->a_v = p->p_ucred->cr_uid; 419 a++; 420 421 a->a_type = LINUX_AT_GID; 422 a->a_v = p->p_cred->p_rgid; 423 a++; 424 425 a->a_type = LINUX_AT_EGID; 426 if (vap->va_mode & S_ISGID) 427 a->a_v = vap->va_gid; 428 else 429 a->a_v = p->p_ucred->cr_gid; 430 a++; 431 432 a->a_type = AT_NULL; 433 a->a_v = 0; 434 a++; 435 436 len = (a - ai) * sizeof(AuxInfo); 437 if ((error = copyout(ai, *stackp, len)) != 0) 438 return error; 439 *stackp += len; 440 441 return 0; 442 } 443 #endif /* !LINUX_MACHDEP_ELF_COPYARGS */ 444