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linux_exec_elf32.c revision 1.42.2.4
      1 /*	$NetBSD: linux_exec_elf32.c,v 1.42.2.4 2001/01/05 17:35:26 bouyer Exp $	*/
      2 
      3 /*-
      4  * Copyright (c) 1995, 1998, 2000 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 and Eric Haszlakiewicz.
      9  *
     10  * Redistribution and use in source and binary forms, with or without
     11  * modification, are permitted provided that the following conditions
     12  * are met:
     13  * 1. Redistributions of source code must retain the above copyright
     14  *    notice, this list of conditions and the following disclaimer.
     15  * 2. Redistributions in binary form must reproduce the above copyright
     16  *    notice, this list of conditions and the following disclaimer in the
     17  *    documentation and/or other materials provided with the distribution.
     18  * 3. All advertising materials mentioning features or use of this software
     19  *    must display the following acknowledgement:
     20  *	This product includes software developed by the NetBSD
     21  *	Foundation, Inc. and its contributors.
     22  * 4. Neither the name of The NetBSD Foundation nor the names of its
     23  *    contributors may be used to endorse or promote products derived
     24  *    from this software without specific prior written permission.
     25  *
     26  * THIS SOFTWARE IS PROVIDED BY THE NETBSD FOUNDATION, INC. AND CONTRIBUTORS
     27  * ``AS IS'' AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED
     28  * TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR
     29  * PURPOSE ARE DISCLAIMED.  IN NO EVENT SHALL THE FOUNDATION OR CONTRIBUTORS
     30  * BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
     31  * CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
     32  * SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
     33  * INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
     34  * CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
     35  * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
     36  * POSSIBILITY OF SUCH DAMAGE.
     37  */
     38 
     39 /*
     40  * based on exec_aout.c, sunos_exec.c and svr4_exec.c
     41  */
     42 
     43 #ifndef ELFSIZE
     44 #define	ELFSIZE		32				/* XXX should die */
     45 #endif
     46 
     47 #include <sys/param.h>
     48 #include <sys/systm.h>
     49 #include <sys/kernel.h>
     50 #include <sys/proc.h>
     51 #include <sys/malloc.h>
     52 #include <sys/namei.h>
     53 #include <sys/vnode.h>
     54 #include <sys/mount.h>
     55 #include <sys/exec.h>
     56 #include <sys/exec_elf.h>
     57 
     58 #include <sys/mman.h>
     59 #include <sys/syscallargs.h>
     60 
     61 #include <machine/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 
     70 #include <compat/linux/linux_syscallargs.h>
     71 #include <compat/linux/linux_syscall.h>
     72 
     73 static int ELFNAME2(linux,signature) __P((struct proc *, struct exec_package *,
     74 	Elf_Ehdr *, char *));
     75 #ifdef LINUX_GCC_SIGNATURE
     76 static int ELFNAME2(linux,gcc_signature) __P((struct proc *p,
     77 	struct exec_package *, Elf_Ehdr *));
     78 #endif
     79 
     80 #ifdef LINUX_GCC_SIGNATURE
     81 /*
     82  * Take advantage of the fact that all the linux binaries are compiled
     83  * with gcc, and gcc sticks in the comment field a signature. Note that
     84  * on SVR4 binaries, the gcc signature will follow the OS name signature,
     85  * that will not be a problem. We don't bother to read in the string table,
     86  * but we check all the progbits headers.
     87  *
     88  * XXX This only works in the i386.  On the alpha (at least)
     89  * XXX we have the same gcc signature which incorrectly identifies
     90  * XXX NetBSD binaries as Linux.
     91  */
     92 static int
     93 ELFNAME2(linux,gcc_signature)(p, epp, eh)
     94 	struct proc *p;
     95 	struct exec_package *epp;
     96 	Elf_Ehdr *eh;
     97 {
     98 	size_t shsize;
     99 	size_t i;
    100 	static const char signature[] = "\0GCC: (GNU) ";
    101 	char buf[sizeof(signature) - 1];
    102 	Elf_Shdr *sh;
    103 	int error;
    104 
    105 	shsize = eh->e_shnum * sizeof(Elf_Shdr);
    106 	sh = (Elf_Shdr *) malloc(shsize, M_TEMP, M_WAITOK);
    107 	error = ELFNAME(read_from)(p, epp->ep_vp, eh->e_shoff, (caddr_t)sh,
    108 	    shsize);
    109 	if (error)
    110 		goto out;
    111 
    112 	for (i = 0; i < eh->e_shnum; i++) {
    113 		Elf_Shdr *s = &sh[i];
    114 
    115 		/*
    116 		 * Identify candidates for the comment header;
    117 		 * Header cannot have a load address, or flags and
    118 		 * it must be large enough.
    119 		 */
    120 		if (s->sh_type != SHT_PROGBITS ||
    121 		    s->sh_addr != 0 ||
    122 		    s->sh_flags != 0 ||
    123 		    s->sh_size < sizeof(signature) - 1)
    124 			continue;
    125 
    126 		error = ELFNAME(read_from)(p, epp->ep_vp, s->sh_offset,
    127 		    (caddr_t)buf, sizeof(signature) - 1);
    128 		if (error)
    129 			continue;
    130 
    131 		/*
    132 		 * error is 0, if the signatures match we are done.
    133 		 */
    134 #ifdef DEBUG_LINUX
    135 		printf("linux_gcc_sig: sig=%s\n", buf);
    136 #endif
    137 		if (!memcmp(buf, signature, sizeof(signature) - 1)) {
    138 			error = 0;
    139 			goto out;
    140 		}
    141 	}
    142 	error = ENOEXEC;
    143 
    144 out:
    145 	free(sh, M_TEMP);
    146 	return (error);
    147 }
    148 #endif
    149 
    150 static int
    151 ELFNAME2(linux,signature)(p, epp, eh, itp)
    152 	struct proc *p;
    153 	struct exec_package *epp;
    154 	Elf_Ehdr *eh;
    155 	char *itp;
    156 {
    157 	size_t i;
    158 	Elf_Phdr *ph;
    159 	size_t phsize;
    160 	int error;
    161 
    162 	phsize = eh->e_phnum * sizeof(Elf_Phdr);
    163 	ph = (Elf_Phdr *)malloc(phsize, M_TEMP, M_WAITOK);
    164 	error = ELFNAME(read_from)(p, epp->ep_vp, eh->e_phoff, (caddr_t)ph,
    165 	    phsize);
    166 	if (error)
    167 		goto out;
    168 
    169 	for (i = 0; i < eh->e_phnum; i++) {
    170 		Elf_Phdr *ephp = &ph[i];
    171 		Elf_Nhdr *np;
    172 		u_int32_t *abi;
    173 
    174 		if (ephp->p_type != PT_NOTE ||
    175 		    ephp->p_filesz > 1024 ||
    176 		    ephp->p_filesz < sizeof(Elf_Nhdr) + 20)
    177 			continue;
    178 
    179 		np = (Elf_Nhdr *)malloc(ephp->p_filesz, M_TEMP, M_WAITOK);
    180 		error = ELFNAME(read_from)(p, epp->ep_vp, ephp->p_offset,
    181 		    (caddr_t)np, ephp->p_filesz);
    182 		if (error)
    183 			goto next;
    184 
    185 		if (np->n_type != ELF_NOTE_TYPE_ABI_TAG ||
    186 		    np->n_namesz != ELF_NOTE_ABI_NAMESZ ||
    187 		    np->n_descsz != ELF_NOTE_ABI_DESCSZ ||
    188 		    memcmp((caddr_t)(np + 1), ELF_NOTE_ABI_NAME,
    189 		    ELF_NOTE_ABI_NAMESZ))
    190 			goto next;
    191 
    192 		/* Make sure the OS is Linux. */
    193 		abi = (u_int32_t *)((caddr_t)np + sizeof(Elf_Nhdr) +
    194 		    np->n_namesz);
    195 		if (abi[0] == ELF_NOTE_ABI_OS_LINUX)
    196 			error = 0;
    197 		else
    198 			error = ENOEXEC;
    199 		free(np, M_TEMP);
    200 		goto out;
    201 
    202 	next:
    203 		free(np, M_TEMP);
    204 		continue;
    205 	}
    206 
    207 	/* Check for certain intepreter names. */
    208 	if (itp[0]) {
    209 		if (!strncmp(itp, "/lib/ld-linux", 13) ||
    210 		    !strncmp(itp, "/lib/ld.so.", 11))
    211 			error = 0;
    212 		else
    213 			error = ENOEXEC;
    214 		goto out;
    215 	}
    216 
    217 	error = ENOEXEC;
    218 out:
    219 	free(ph, M_TEMP);
    220 	return (error);
    221 }
    222 
    223 int
    224 ELFNAME2(linux,probe)(p, epp, eh, itp, pos)
    225 	struct proc *p;
    226 	struct exec_package *epp;
    227 	void *eh;
    228 	char *itp;
    229 	vaddr_t *pos;
    230 {
    231 	const char *bp;
    232 	int error;
    233 	size_t len;
    234 
    235 	if ((error = ELFNAME2(linux,signature)(p, epp, eh, itp)) != 0)
    236 #ifdef LINUX_GCC_SIGNATURE
    237 		if ((error = ELFNAME2(linux,gcc_signature)(p, epp, eh)) != 0)
    238 			return error;
    239 #else
    240 		return error;
    241 #endif
    242 
    243 	if (itp[0]) {
    244 		if ((error = emul_find(p, NULL, epp->ep_esch->es_emul->e_path,
    245 		    itp, &bp, 0)))
    246 			return error;
    247 		if ((error = copystr(bp, itp, MAXPATHLEN, &len)))
    248 			return error;
    249 		free((void *)bp, M_TEMP);
    250 	}
    251 	*pos = ELF_NO_ADDR;
    252 #ifdef DEBUG_LINUX
    253 	printf("linux_probe: returning 0\n");
    254 #endif
    255 	return 0;
    256 }
    257 
    258