linux_exec_elf32.c revision 1.55
1 /* $NetBSD: linux_exec_elf32.c,v 1.55 2002/02/15 20:02:56 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 1.55 2002/02/15 20:02:56 christos Exp $"); 46 47 #ifndef ELFSIZE 48 #define ELFSIZE 32 /* XXX should die */ 49 #endif 50 51 #include <sys/param.h> 52 #include <sys/systm.h> 53 #include <sys/kernel.h> 54 #include <sys/proc.h> 55 #include <sys/malloc.h> 56 #include <sys/namei.h> 57 #include <sys/vnode.h> 58 #include <sys/mount.h> 59 #include <sys/exec.h> 60 #include <sys/exec_elf.h> 61 62 #include <sys/mman.h> 63 #include <sys/syscallargs.h> 64 65 #include <machine/cpu.h> 66 #include <machine/reg.h> 67 68 #include <compat/linux/common/linux_types.h> 69 #include <compat/linux/common/linux_signal.h> 70 #include <compat/linux/common/linux_util.h> 71 #include <compat/linux/common/linux_exec.h> 72 #include <compat/linux/common/linux_machdep.h> 73 74 #include <compat/linux/linux_syscallargs.h> 75 #include <compat/linux/linux_syscall.h> 76 77 static int ELFNAME2(linux,signature) __P((struct proc *, struct exec_package *, 78 Elf_Ehdr *, char *)); 79 #ifdef LINUX_GCC_SIGNATURE 80 static int ELFNAME2(linux,gcc_signature) __P((struct proc *p, 81 struct exec_package *, Elf_Ehdr *)); 82 #endif 83 #ifdef LINUX_ATEXIT_SIGNATURE 84 static int ELFNAME2(linux,atexit_signature) __P((struct proc *p, 85 struct exec_package *, Elf_Ehdr *)); 86 #endif 87 88 #ifdef LINUX_ATEXIT_SIGNATURE 89 /* 90 * On the PowerPC, statically linked Linux binaries are not recognized 91 * by linux_signature nor by linux_gcc_signature. Fortunately, thoses 92 * binaries features a __libc_atexit ELF section. We therefore assume we 93 * have a Linux binary if we find this section. 94 */ 95 static int 96 ELFNAME2(linux,atexit_signature)(p, epp, eh) 97 struct proc *p; 98 struct exec_package *epp; 99 Elf_Ehdr *eh; 100 { 101 size_t shsize; 102 int strndx; 103 size_t i; 104 static const char signature[] = "__libc_atexit"; 105 char* strtable; 106 Elf_Shdr *sh; 107 108 int error; 109 110 /* 111 * load the section header table 112 */ 113 shsize = eh->e_shnum * sizeof(Elf_Shdr); 114 sh = (Elf_Shdr *) malloc(shsize, M_TEMP, M_WAITOK); 115 error = exec_read_from(p, epp->ep_vp, eh->e_shoff, sh, shsize); 116 if (error) 117 goto out; 118 119 /* 120 * Now let's find the string table. If it does not exists, give up. 121 */ 122 strndx = (int)(eh->e_shstrndx); 123 if (strndx == SHN_UNDEF) { 124 error = ENOEXEC; 125 goto out; 126 } 127 128 /* 129 * strndx is the index in section header table of the string table 130 * section get the whole string table in strtable, and then we get access to the names 131 * s->sh_name is the offset of the section name in strtable. 132 */ 133 strtable = malloc(sh[strndx].sh_size, M_TEMP, M_WAITOK); 134 error = exec_read_from(p, epp->ep_vp, sh[strndx].sh_offset, strtable, 135 sh[strndx].sh_size); 136 if (error) 137 goto out; 138 139 for (i = 0; i < eh->e_shnum; i++) { 140 Elf_Shdr *s = &sh[i]; 141 if (!memcmp((void*)(&(strtable[s->sh_name])), signature, 142 sizeof(signature))) { 143 #ifdef DEBUG_LINUX 144 uprintf("linux_atexit_sig=%s\n", 145 &(strtable[s->sh_name])); 146 #endif 147 error = 0; 148 goto out; 149 } 150 } 151 error = ENOEXEC; 152 153 out: 154 free(sh, M_TEMP); 155 free(strtable, M_TEMP); 156 return (error); 157 } 158 #endif 159 160 #ifdef LINUX_GCC_SIGNATURE 161 /* 162 * Take advantage of the fact that all the linux binaries are compiled 163 * with gcc, and gcc sticks in the comment field a signature. Note that 164 * on SVR4 binaries, the gcc signature will follow the OS name signature, 165 * that will not be a problem. We don't bother to read in the string table, 166 * but we check all the progbits headers. 167 * 168 * XXX This only works in the i386. On the alpha (at least) 169 * XXX we have the same gcc signature which incorrectly identifies 170 * XXX NetBSD binaries as Linux. 171 */ 172 static int 173 ELFNAME2(linux,gcc_signature)(p, epp, eh) 174 struct proc *p; 175 struct exec_package *epp; 176 Elf_Ehdr *eh; 177 { 178 size_t shsize; 179 size_t i; 180 static const char signature[] = "\0GCC: (GNU) "; 181 char buf[sizeof(signature) - 1]; 182 Elf_Shdr *sh; 183 int error; 184 185 shsize = eh->e_shnum * sizeof(Elf_Shdr); 186 sh = (Elf_Shdr *) malloc(shsize, M_TEMP, M_WAITOK); 187 error = exec_read_from(p, epp->ep_vp, eh->e_shoff, sh, shsize); 188 if (error) 189 goto out; 190 191 for (i = 0; i < eh->e_shnum; i++) { 192 Elf_Shdr *s = &sh[i]; 193 194 /* 195 * Identify candidates for the comment header; 196 * Header cannot have a load address, or flags and 197 * it must be large enough. 198 */ 199 if (s->sh_type != SHT_PROGBITS || 200 s->sh_addr != 0 || 201 s->sh_flags != 0 || 202 s->sh_size < sizeof(signature) - 1) 203 continue; 204 205 error = exec_read_from(p, epp->ep_vp, s->sh_offset, buf, 206 sizeof(signature) - 1); 207 if (error) 208 continue; 209 210 /* 211 * error is 0, if the signatures match we are done. 212 */ 213 #ifdef DEBUG_LINUX 214 uprintf("linux_gcc_sig: sig=%s\n", buf); 215 #endif 216 if (!memcmp(buf, signature, sizeof(signature) - 1)) { 217 error = 0; 218 goto out; 219 } 220 } 221 error = ENOEXEC; 222 223 out: 224 free(sh, M_TEMP); 225 return (error); 226 } 227 #endif 228 229 static int 230 ELFNAME2(linux,signature)(p, epp, eh, itp) 231 struct proc *p; 232 struct exec_package *epp; 233 Elf_Ehdr *eh; 234 char *itp; 235 { 236 size_t i; 237 Elf_Phdr *ph; 238 size_t phsize; 239 int error; 240 241 phsize = eh->e_phnum * sizeof(Elf_Phdr); 242 ph = (Elf_Phdr *)malloc(phsize, M_TEMP, M_WAITOK); 243 error = exec_read_from(p, epp->ep_vp, eh->e_phoff, ph, phsize); 244 if (error) 245 goto out; 246 247 for (i = 0; i < eh->e_phnum; i++) { 248 Elf_Phdr *ephp = &ph[i]; 249 Elf_Nhdr *np; 250 u_int32_t *abi; 251 252 if (ephp->p_type != PT_NOTE || 253 ephp->p_filesz > 1024 || 254 ephp->p_filesz < sizeof(Elf_Nhdr) + 20) 255 continue; 256 257 np = (Elf_Nhdr *)malloc(ephp->p_filesz, M_TEMP, M_WAITOK); 258 error = exec_read_from(p, epp->ep_vp, ephp->p_offset, np, 259 ephp->p_filesz); 260 if (error) 261 goto next; 262 263 if (np->n_type != ELF_NOTE_TYPE_ABI_TAG || 264 np->n_namesz != ELF_NOTE_ABI_NAMESZ || 265 np->n_descsz != ELF_NOTE_ABI_DESCSZ || 266 memcmp((caddr_t)(np + 1), ELF_NOTE_ABI_NAME, 267 ELF_NOTE_ABI_NAMESZ)) 268 goto next; 269 270 /* Make sure the OS is Linux. */ 271 abi = (u_int32_t *)((caddr_t)np + sizeof(Elf_Nhdr) + 272 np->n_namesz); 273 if (abi[0] == ELF_NOTE_ABI_OS_LINUX) 274 error = 0; 275 else 276 error = ENOEXEC; 277 free(np, M_TEMP); 278 goto out; 279 280 next: 281 free(np, M_TEMP); 282 continue; 283 } 284 285 /* Check for certain intepreter names. */ 286 if (itp[0]) { 287 if (!strncmp(itp, "/lib/ld-linux", 13) || 288 !strncmp(itp, "/lib/ld.so.", 11)) 289 error = 0; 290 else 291 error = ENOEXEC; 292 goto out; 293 } 294 295 error = ENOEXEC; 296 out: 297 free(ph, M_TEMP); 298 return (error); 299 } 300 301 int 302 ELFNAME2(linux,probe)(p, epp, eh, itp, pos) 303 struct proc *p; 304 struct exec_package *epp; 305 void *eh; 306 char *itp; 307 vaddr_t *pos; 308 { 309 const char *bp; 310 int error; 311 size_t len; 312 313 if (((error = ELFNAME2(linux,signature)(p, epp, eh, itp)) != 0) && 314 #ifdef LINUX_GCC_SIGNATURE 315 ((error = ELFNAME2(linux,gcc_signature)(p, epp, eh)) != 0) && 316 #endif 317 #ifdef LINUX_ATEXIT_SIGNATURE 318 ((error = ELFNAME2(linux,atexit_signature)(p, epp, eh)) != 0) && 319 #endif 320 1) 321 return error; 322 323 if (itp[0]) { 324 if ((error = emul_find(p, NULL, epp->ep_esch->es_emul->e_path, 325 itp, &bp, 0))) 326 return error; 327 if ((error = copystr(bp, itp, MAXPATHLEN, &len))) 328 return error; 329 free((void *)bp, M_TEMP); 330 } 331 *pos = ELF_NO_ADDR; 332 #ifdef DEBUG_LINUX 333 uprintf("linux_probe: returning 0\n"); 334 #endif 335 return 0; 336 } 337 338
Indexes created Mon Sep 22 05:09:51 GMT 2025