422 lines
11 KiB
C
422 lines
11 KiB
C
/*
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* Copyright (c) 1997 Christopher G. Demetriou. All rights reserved.
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*
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* Redistribution and use in source and binary forms, with or without
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* modification, are permitted provided that the following conditions
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* are met:
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* 1. Redistributions of source code must retain the above copyright
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* notice, this list of conditions and the following disclaimer.
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* 2. Redistributions in binary form must reproduce the above copyright
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* notice, this list of conditions and the following disclaimer in the
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* documentation and/or other materials provided with the distribution.
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* 3. All advertising materials mentioning features or use of this software
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* must display the following acknowledgement:
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* This product includes software developed by Christopher G. Demetriou
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* for the NetBSD Project.
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* 4. The name of the author may not be used to endorse or promote products
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* derived from this software without specific prior written permission
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*
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* THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR
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* IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
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* OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED.
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* IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT,
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* INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT
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* NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
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* DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
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* THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
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* (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF
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* THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
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*/
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#include <sys/cdefs.h>
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#ifndef lint
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#if 0
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__RCSID("$NetBSD: exec_elf32.c,v 1.4 1997/08/12 06:07:24 mikel Exp $");
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#endif
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#endif
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__FBSDID("$FreeBSD$");
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#ifndef ELFSIZE
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#define ELFSIZE 32
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#endif
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#include <sys/types.h>
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#include <sys/endian.h>
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#include <sys/stat.h>
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#include <errno.h>
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#include <stdio.h>
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#include <stdlib.h>
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#include <string.h>
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#include <unistd.h>
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#include "extern.h"
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#if (defined(NLIST_ELF32) && (ELFSIZE == 32)) || \
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(defined(NLIST_ELF64) && (ELFSIZE == 64))
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#define __ELF_WORD_SIZE ELFSIZE
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#if (ELFSIZE == 32)
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#include <sys/elf32.h>
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#define xewtoh(x) ((data == ELFDATA2MSB) ? be32toh(x) : le32toh(x))
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#define htoxew(x) ((data == ELFDATA2MSB) ? htobe32(x) : htole32(x))
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#elif (ELFSIZE == 64)
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#include <sys/elf64.h>
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#define xewtoh(x) ((data == ELFDATA2MSB) ? be64toh(x) : le64toh(x))
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#define htoxew(x) ((data == ELFDATA2MSB) ? htobe64(x) : htole64(x))
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#endif
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#include <sys/elf_generic.h>
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#define CONCAT(x,y) __CONCAT(x,y)
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#define ELFNAME(x) CONCAT(elf,CONCAT(ELFSIZE,CONCAT(_,x)))
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#define ELFNAME2(x,y) CONCAT(x,CONCAT(_elf,CONCAT(ELFSIZE,CONCAT(_,y))))
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#define ELFNAMEEND(x) CONCAT(x,CONCAT(_elf,ELFSIZE))
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#define ELFDEFNNAME(x) CONCAT(ELF,CONCAT(ELFSIZE,CONCAT(_,x)))
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#define xe16toh(x) ((data == ELFDATA2MSB) ? be16toh(x) : le16toh(x))
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#define xe32toh(x) ((data == ELFDATA2MSB) ? be32toh(x) : le32toh(x))
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#define htoxe32(x) ((data == ELFDATA2MSB) ? htobe32(x) : htole32(x))
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struct listelem {
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struct listelem *next;
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void *mem;
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off_t file;
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size_t size;
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};
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static ssize_t
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xreadatoff(int fd, void *buf, off_t off, size_t size, const char *fn)
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{
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ssize_t rv;
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if (lseek(fd, off, SEEK_SET) != off) {
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perror(fn);
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return -1;
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}
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if ((rv = read(fd, buf, size)) != size) {
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fprintf(stderr, "%s: read error: %s\n", fn,
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rv == -1 ? strerror(errno) : "short read");
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return -1;
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}
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return size;
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}
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static ssize_t
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xwriteatoff(int fd, void *buf, off_t off, size_t size, const char *fn)
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{
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ssize_t rv;
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if (lseek(fd, off, SEEK_SET) != off) {
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perror(fn);
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return -1;
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}
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if ((rv = write(fd, buf, size)) != size) {
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fprintf(stderr, "%s: write error: %s\n", fn,
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rv == -1 ? strerror(errno) : "short write");
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return -1;
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}
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return size;
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}
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static void *
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xmalloc(size_t size, const char *fn, const char *use)
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{
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void *rv;
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rv = malloc(size);
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if (rv == NULL)
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fprintf(stderr, "%s: out of memory (allocating for %s)\n",
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fn, use);
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return (rv);
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}
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int
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ELFNAMEEND(check)(int fd, const char *fn)
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{
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Elf_Ehdr eh;
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struct stat sb;
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unsigned char data;
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/*
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* Check the header to maek sure it's an ELF file (of the
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* appropriate size).
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*/
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if (fstat(fd, &sb) == -1)
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return 0;
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if (sb.st_size < sizeof eh)
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return 0;
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if (read(fd, &eh, sizeof eh) != sizeof eh)
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return 0;
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if (IS_ELF(eh) == 0)
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return 0;
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data = eh.e_ident[EI_DATA];
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switch (xe16toh(eh.e_machine)) {
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case EM_386: break;
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case EM_ALPHA: break;
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#ifndef EM_IA_64
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#define EM_IA_64 50
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#endif
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case EM_IA_64: break;
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#ifndef EM_PPC
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#define EM_PPC 20
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#endif
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case EM_PPC: break;
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#ifndef EM_SPARCV9
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#define EM_SPARCV9 43
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#endif
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case EM_SPARCV9: break;
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#ifndef EM_X86_64
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#define EM_X86_64 62
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#endif
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case EM_X86_64: break;
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/* ELFDEFNNAME(MACHDEP_ID_CASES) */
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default:
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return 0;
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}
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return 1;
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}
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int
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ELFNAMEEND(hide)(int fd, const char *fn)
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{
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Elf_Ehdr ehdr;
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Elf_Shdr *shdrp = NULL, *symtabshdr, *strtabshdr;
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Elf_Sym *symtabp = NULL;
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char *strtabp = NULL;
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Elf_Word *symfwmap = NULL, *symrvmap = NULL, nsyms, nlocalsyms, ewi;
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struct listelem *relalist = NULL, *rellist = NULL, *tmpl;
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ssize_t shdrsize;
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int rv, i, weird;
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unsigned char data;
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rv = 0;
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if (xreadatoff(fd, &ehdr, 0, sizeof ehdr, fn) != sizeof ehdr)
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goto bad;
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data = ehdr.e_ident[EI_DATA];
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shdrsize = xe16toh(ehdr.e_shnum) * xe16toh(ehdr.e_shentsize);
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if ((shdrp = xmalloc(shdrsize, fn, "section header table")) == NULL)
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goto bad;
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if (xreadatoff(fd, shdrp, xewtoh(ehdr.e_shoff), shdrsize, fn) !=
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shdrsize)
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goto bad;
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symtabshdr = strtabshdr = NULL;
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weird = 0;
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for (i = 0; i < xe16toh(ehdr.e_shnum); i++) {
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switch (xe32toh(shdrp[i].sh_type)) {
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case SHT_SYMTAB:
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if (symtabshdr != NULL)
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weird = 1;
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symtabshdr = &shdrp[i];
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strtabshdr = &shdrp[xe32toh(shdrp[i].sh_link)];
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break;
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case SHT_RELA:
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tmpl = xmalloc(sizeof *tmpl, fn, "rela list element");
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if (tmpl == NULL)
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goto bad;
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tmpl->mem = NULL;
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tmpl->file = xewtoh(shdrp[i].sh_offset);
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tmpl->size = xewtoh(shdrp[i].sh_size);
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tmpl->next = relalist;
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relalist = tmpl;
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break;
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case SHT_REL:
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tmpl = xmalloc(sizeof *tmpl, fn, "rel list element");
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if (tmpl == NULL)
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goto bad;
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tmpl->mem = NULL;
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tmpl->file = xewtoh(shdrp[i].sh_offset);
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tmpl->size = xewtoh(shdrp[i].sh_size);
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tmpl->next = rellist;
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rellist = tmpl;
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break;
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}
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}
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if (symtabshdr == NULL)
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goto out;
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if (strtabshdr == NULL)
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weird = 1;
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if (weird) {
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fprintf(stderr, "%s: weird executable (unsupported)\n", fn);
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goto bad;
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}
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/*
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* load up everything we need
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*/
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/* symbol table */
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if ((symtabp = xmalloc(xewtoh(symtabshdr->sh_size), fn, "symbol table"))
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== NULL)
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goto bad;
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if (xreadatoff(fd, symtabp, xewtoh(symtabshdr->sh_offset),
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xewtoh(symtabshdr->sh_size), fn) != xewtoh(symtabshdr->sh_size))
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goto bad;
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/* string table */
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if ((strtabp = xmalloc(xewtoh(strtabshdr->sh_size), fn, "string table"))
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== NULL)
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goto bad;
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if (xreadatoff(fd, strtabp, xewtoh(strtabshdr->sh_offset),
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xewtoh(strtabshdr->sh_size), fn) != xewtoh(strtabshdr->sh_size))
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goto bad;
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/* any rela tables */
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for (tmpl = relalist; tmpl != NULL; tmpl = tmpl->next) {
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if ((tmpl->mem = xmalloc(tmpl->size, fn, "rela table"))
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== NULL)
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goto bad;
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if (xreadatoff(fd, tmpl->mem, tmpl->file,
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tmpl->size, fn) != tmpl->size)
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goto bad;
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}
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/* any rel tables */
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for (tmpl = rellist; tmpl != NULL; tmpl = tmpl->next) {
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if ((tmpl->mem = xmalloc(tmpl->size, fn, "rel table"))
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== NULL)
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goto bad;
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if (xreadatoff(fd, tmpl->mem, tmpl->file,
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tmpl->size, fn) != tmpl->size)
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goto bad;
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}
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/* Prepare data structures for symbol movement. */
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nsyms = xewtoh(symtabshdr->sh_size) / xewtoh(symtabshdr->sh_entsize);
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nlocalsyms = xe32toh(symtabshdr->sh_info);
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if ((symfwmap = xmalloc(nsyms * sizeof (Elf_Word), fn,
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"symbol forward mapping table")) == NULL)
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goto bad;
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if ((symrvmap = xmalloc(nsyms * sizeof (Elf_Word), fn,
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"symbol reverse mapping table")) == NULL)
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goto bad;
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/* init location -> symbol # table */
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for (ewi = 0; ewi < nsyms; ewi++)
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symrvmap[ewi] = ewi;
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/* move symbols, making them local */
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for (ewi = nlocalsyms; ewi < nsyms; ewi++) {
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Elf_Sym *sp, symswap;
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Elf_Word mapswap;
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sp = &symtabp[ewi];
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/* if it's on our keep list, don't move it */
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if (in_keep_list(strtabp + xe32toh(sp->st_name)))
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continue;
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/* if it's an undefined symbol, keep it */
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if (xe16toh(sp->st_shndx) == SHN_UNDEF)
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continue;
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/* adjust the symbol so that it's local */
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sp->st_info =
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ELF_ST_INFO(STB_LOCAL, sp->st_info);
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/* (STB_LOCAL << 4) | ELF_SYM_TYPE(sp->st_info); *//* XXX */
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/*
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* move the symbol to its new location
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*/
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/* note that symbols in those locations have been swapped */
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mapswap = symrvmap[ewi];
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symrvmap[ewi] = symrvmap[nlocalsyms];
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symrvmap[nlocalsyms] = mapswap;
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/* and swap the symbols */
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symswap = *sp;
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*sp = symtabp[nlocalsyms];
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symtabp[nlocalsyms] = symswap;
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nlocalsyms++; /* note new local sym */
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}
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symtabshdr->sh_info = htoxe32(nlocalsyms);
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/* set up symbol # -> location mapping table */
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for (ewi = 0; ewi < nsyms; ewi++)
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symfwmap[symrvmap[ewi]] = ewi;
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/* any rela tables */
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for (tmpl = relalist; tmpl != NULL; tmpl = tmpl->next) {
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Elf_Rela *relap = tmpl->mem;
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for (ewi = 0; ewi < tmpl->size / sizeof(*relap); ewi++) {
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relap[ewi].r_info = htoxew(ELF_R_INFO(
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symfwmap[ELF_R_SYM(xewtoh(relap[ewi].r_info))],
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ELF_R_TYPE(xewtoh(relap[ewi].r_info))
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));
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}
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}
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/* any rel tables */
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for (tmpl = rellist; tmpl != NULL; tmpl = tmpl->next) {
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Elf_Rel *relp = tmpl->mem;
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for (ewi = 0; ewi < tmpl->size / sizeof *relp; ewi++) {
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relp[ewi].r_info = htoxew(ELF_R_INFO(
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symfwmap[ELF_R_SYM(xewtoh(relp[ewi].r_info))],
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ELF_R_TYPE(xewtoh(relp[ewi].r_info))
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));
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}
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}
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/*
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* write new tables to the file
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*/
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if (xwriteatoff(fd, shdrp, xewtoh(ehdr.e_shoff), shdrsize, fn) !=
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shdrsize)
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goto bad;
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if (xwriteatoff(fd, symtabp, xewtoh(symtabshdr->sh_offset),
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xewtoh(symtabshdr->sh_size), fn) != xewtoh(symtabshdr->sh_size))
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goto bad;
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for (tmpl = relalist; tmpl != NULL; tmpl = tmpl->next) {
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if (xwriteatoff(fd, tmpl->mem, tmpl->file,
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tmpl->size, fn) != tmpl->size)
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goto bad;
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}
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for (tmpl = rellist; tmpl != NULL; tmpl = tmpl->next) {
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if (xwriteatoff(fd, tmpl->mem, tmpl->file,
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tmpl->size, fn) != tmpl->size)
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goto bad;
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}
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out:
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if (shdrp != NULL)
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free(shdrp);
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if (symtabp != NULL)
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free(symtabp);
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if (strtabp != NULL)
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free(strtabp);
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if (symfwmap != NULL)
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free(symfwmap);
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if (symrvmap != NULL)
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free(symrvmap);
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while ((tmpl = relalist) != NULL) {
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relalist = tmpl->next;
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if (tmpl->mem != NULL)
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free(tmpl->mem);
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free(tmpl);
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}
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while ((tmpl = rellist) != NULL) {
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rellist = tmpl->next;
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if (tmpl->mem != NULL)
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free(tmpl->mem);
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free(tmpl);
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}
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return (rv);
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bad:
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rv = 1;
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goto out;
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}
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#endif /* include this size of ELF */
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