linux_exec_elf32.c revision 1.51.2.5
1 /* $NetBSD: linux_exec_elf32.c,v 1.51.2.5 2002/04/01 07:44:24 nathanw 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 1.51.2.5 2002/04/01 07:44:24 nathanw 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 DEBUG_LINUX 89 #define DPRINTF(a) uprintf a 90 #else 91 #define DPRINTF(a) 92 #endif 93 94 #ifdef LINUX_ATEXIT_SIGNATURE 95 /* 96 * On the PowerPC, statically linked Linux binaries are not recognized 97 * by linux_signature nor by linux_gcc_signature. Fortunately, thoses 98 * binaries features a __libc_atexit ELF section. We therefore assume we 99 * have a Linux binary if we find this section. 100 */ 101 static int 102 ELFNAME2(linux,atexit_signature)(p, epp, eh) 103 struct proc *p; 104 struct exec_package *epp; 105 Elf_Ehdr *eh; 106 { 107 size_t shsize; 108 int strndx; 109 size_t i; 110 static const char signature[] = "__libc_atexit"; 111 char* strtable; 112 Elf_Shdr *sh; 113 114 int error; 115 116 /* 117 * load the section header table 118 */ 119 shsize = eh->e_shnum * sizeof(Elf_Shdr); 120 sh = (Elf_Shdr *) malloc(shsize, M_TEMP, M_WAITOK); 121 error = exec_read_from(p, epp->ep_vp, eh->e_shoff, sh, shsize); 122 if (error) 123 goto out; 124 125 /* 126 * Now let's find the string table. If it does not exists, give up. 127 */ 128 strndx = (int)(eh->e_shstrndx); 129 if (strndx == SHN_UNDEF) { 130 error = ENOEXEC; 131 goto out; 132 } 133 134 /* 135 * strndx is the index in section header table of the string table 136 * section get the whole string table in strtable, and then we get access to the names 137 * s->sh_name is the offset of the section name in strtable. 138 */ 139 strtable = malloc(sh[strndx].sh_size, M_TEMP, M_WAITOK); 140 error = exec_read_from(p, epp->ep_vp, sh[strndx].sh_offset, strtable, 141 sh[strndx].sh_size); 142 if (error) 143 goto out; 144 145 for (i = 0; i < eh->e_shnum; i++) { 146 Elf_Shdr *s = &sh[i]; 147 if (!memcmp((void*)(&(strtable[s->sh_name])), signature, 148 sizeof(signature))) { 149 DPRINTF(("linux_atexit_sig=%s\n", 150 &(strtable[s->sh_name]))); 151 error = 0; 152 goto out; 153 } 154 } 155 error = ENOEXEC; 156 157 out: 158 free(sh, M_TEMP); 159 free(strtable, M_TEMP); 160 return (error); 161 } 162 #endif 163 164 #ifdef LINUX_GCC_SIGNATURE 165 /* 166 * Take advantage of the fact that all the linux binaries are compiled 167 * with gcc, and gcc sticks in the comment field a signature. Note that 168 * on SVR4 binaries, the gcc signature will follow the OS name signature, 169 * that will not be a problem. We don't bother to read in the string table, 170 * but we check all the progbits headers. 171 * 172 * XXX This only works in the i386. On the alpha (at least) 173 * XXX we have the same gcc signature which incorrectly identifies 174 * XXX NetBSD binaries as Linux. 175 */ 176 static int 177 ELFNAME2(linux,gcc_signature)(p, epp, eh) 178 struct proc *p; 179 struct exec_package *epp; 180 Elf_Ehdr *eh; 181 { 182 size_t shsize; 183 size_t i; 184 static const char signature[] = "\0GCC: (GNU) "; 185 char buf[sizeof(signature) - 1]; 186 Elf_Shdr *sh; 187 int error; 188 189 shsize = eh->e_shnum * sizeof(Elf_Shdr); 190 sh = (Elf_Shdr *) malloc(shsize, M_TEMP, M_WAITOK); 191 error = exec_read_from(p, epp->ep_vp, eh->e_shoff, sh, shsize); 192 if (error) 193 goto out; 194 195 for (i = 0; i < eh->e_shnum; i++) { 196 Elf_Shdr *s = &sh[i]; 197 198 /* 199 * Identify candidates for the comment header; 200 * Header cannot have a load address, or flags and 201 * it must be large enough. 202 */ 203 if (s->sh_type != SHT_PROGBITS || 204 s->sh_addr != 0 || 205 s->sh_flags != 0 || 206 s->sh_size < sizeof(signature) - 1) 207 continue; 208 209 error = exec_read_from(p, epp->ep_vp, s->sh_offset, buf, 210 sizeof(signature) - 1); 211 if (error) 212 continue; 213 214 /* 215 * error is 0, if the signatures match we are done. 216 */ 217 DPRINTF(("linux_gcc_sig: sig=%s\n", buf)); 218 if (!memcmp(buf, signature, sizeof(signature) - 1)) { 219 error = 0; 220 goto out; 221 } 222 } 223 error = ENOEXEC; 224 225 out: 226 free(sh, M_TEMP); 227 return (error); 228 } 229 #endif 230 231 static int 232 ELFNAME2(linux,signature)(p, epp, eh, itp) 233 struct proc *p; 234 struct exec_package *epp; 235 Elf_Ehdr *eh; 236 char *itp; 237 { 238 size_t i; 239 Elf_Phdr *ph; 240 size_t phsize; 241 int error; 242 243 phsize = eh->e_phnum * sizeof(Elf_Phdr); 244 ph = (Elf_Phdr *)malloc(phsize, M_TEMP, M_WAITOK); 245 error = exec_read_from(p, epp->ep_vp, eh->e_phoff, ph, phsize); 246 if (error) 247 goto out; 248 249 for (i = 0; i < eh->e_phnum; i++) { 250 Elf_Phdr *ephp = &ph[i]; 251 Elf_Nhdr *np; 252 u_int32_t *abi; 253 254 if (ephp->p_type != PT_NOTE || 255 ephp->p_filesz > 1024 || 256 ephp->p_filesz < sizeof(Elf_Nhdr) + 20) 257 continue; 258 259 np = (Elf_Nhdr *)malloc(ephp->p_filesz, M_TEMP, M_WAITOK); 260 error = exec_read_from(p, epp->ep_vp, ephp->p_offset, np, 261 ephp->p_filesz); 262 if (error) 263 goto next; 264 265 if (np->n_type != ELF_NOTE_TYPE_ABI_TAG || 266 np->n_namesz != ELF_NOTE_ABI_NAMESZ || 267 np->n_descsz != ELF_NOTE_ABI_DESCSZ || 268 memcmp((caddr_t)(np + 1), ELF_NOTE_ABI_NAME, 269 ELF_NOTE_ABI_NAMESZ)) 270 goto next; 271 272 /* Make sure the OS is Linux. */ 273 abi = (u_int32_t *)((caddr_t)np + sizeof(Elf_Nhdr) + 274 np->n_namesz); 275 if (abi[0] == ELF_NOTE_ABI_OS_LINUX) 276 error = 0; 277 else 278 error = ENOEXEC; 279 free(np, M_TEMP); 280 goto out; 281 282 next: 283 free(np, M_TEMP); 284 continue; 285 } 286 287 /* Check for certain intepreter names. */ 288 if (itp[0]) { 289 if (!strncmp(itp, "/lib/ld-linux", 13) || 290 !strncmp(itp, "/lib/ld.so.", 11)) 291 error = 0; 292 else 293 error = ENOEXEC; 294 goto out; 295 } 296 297 error = ENOEXEC; 298 out: 299 free(ph, M_TEMP); 300 return (error); 301 } 302 303 int 304 ELFNAME2(linux,probe)(p, epp, eh, itp, pos) 305 struct proc *p; 306 struct exec_package *epp; 307 void *eh; 308 char *itp; 309 vaddr_t *pos; 310 { 311 const char *bp; 312 int error; 313 size_t len; 314 315 if (((error = ELFNAME2(linux,signature)(p, epp, eh, itp)) != 0) && 316 #ifdef LINUX_GCC_SIGNATURE 317 ((error = ELFNAME2(linux,gcc_signature)(p, epp, eh)) != 0) && 318 #endif 319 #ifdef LINUX_ATEXIT_SIGNATURE 320 ((error = ELFNAME2(linux,atexit_signature)(p, epp, eh)) != 0) && 321 #endif 322 1) 323 return error; 324 325 if (itp[0]) { 326 if ((error = emul_find(p, NULL, epp->ep_esch->es_emul->e_path, 327 itp, &bp, 0))) 328 return error; 329 if ((error = copystr(bp, itp, MAXPATHLEN, &len))) 330 return error; 331 free((void *)bp, M_TEMP); 332 } 333 *pos = ELF_NO_ADDR; 334 DPRINTF(("linux_probe: returning 0\n")); 335 return 0; 336 } 337 338
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