1 /* $OpenBSD: exec_elf.c,v 1.13 2011/10/02 22:20:49 edd Exp $ */ 2 3 /* 4 * Copyright (c) 1999 Mats O Jansson. All rights reserved. 5 * 6 * Redistribution and use in source and binary forms, with or without 7 * modification, are permitted provided that the following conditions 8 * are met: 9 * 1. Redistributions of source code must retain the above copyright 10 * notice, this list of conditions and the following disclaimer. 11 * 2. Redistributions in binary form must reproduce the above copyright 12 * notice, this list of conditions and the following disclaimer in the 13 * documentation and/or other materials provided with the distribution. 14 * 15 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR 16 * IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES 17 * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED. 18 * IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT, 19 * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT 20 * NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, 21 * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY 22 * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT 23 * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF 24 * THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE. 25 */ 26 27 #include <sys/types.h> 28 #include <sys/exec.h> 29 #include <sys/exec_elf.h> 30 31 #include <err.h> 32 #include <errno.h> 33 #include <fcntl.h> 34 #include <nlist.h> 35 #include <stdio.h> 36 #include <stdlib.h> 37 #include <unistd.h> 38 39 #include "ukc.h" 40 #include "config.h" 41 42 caddr_t ptr, rest, pre; 43 Elf_Ehdr elf_ex; 44 Elf_Phdr *elf_phdr; 45 Elf_Shdr *elf_shdr; 46 char *elf_total; 47 char *elf_shstrtab; 48 off_t elf_size; 49 50 caddr_t elf_adjust(caddr_t); 51 caddr_t elf_readjust(caddr_t); 52 int elf_check(char *); 53 void elf_loadkernel(char *); 54 void elf_savekernel(char *); 55 56 caddr_t 57 elf_adjust(caddr_t x) 58 { 59 int i; 60 Elf_Shdr *s; 61 unsigned long y = 0; 62 63 s = elf_shdr; 64 65 for (i = 0; i < elf_ex.e_shnum; i++) { 66 if (s[i].sh_addr == 0) 67 continue; 68 if (((unsigned long)x >= s[i].sh_addr) && 69 ((unsigned long)x < (s[i].sh_addr+s[i].sh_size))) { 70 y = (unsigned long)&elf_total[(unsigned long)x - 71 s[i].sh_addr + s[i].sh_offset]; 72 break; 73 } 74 } 75 76 return((caddr_t)y); 77 } 78 79 caddr_t 80 elf_readjust(caddr_t x) 81 { 82 int i; 83 Elf_Shdr *s; 84 unsigned long y = 0; 85 86 s = elf_shdr; 87 88 for (i = 0; i < elf_ex.e_shnum; i++) { 89 if (s[i].sh_addr == 0) 90 continue; 91 if (((x - elf_total) >= s[i].sh_offset) && 92 ((x - elf_total) <= (s[i].sh_offset + s[i].sh_size))) 93 y = (unsigned long)x - (unsigned long)elf_total + 94 (unsigned long)s[i].sh_addr - s[i].sh_offset; 95 } 96 97 return((caddr_t)y); 98 } 99 100 int 101 elf_check(char *file) 102 { 103 int fd, ret = 1; 104 105 if ((fd = open(file, O_RDONLY | O_EXLOCK, 0)) < 0) 106 return (0); 107 108 if (read(fd, (char *)&elf_ex, sizeof(elf_ex)) != sizeof(elf_ex)) 109 ret = 0; 110 111 if (ret) { 112 if (!IS_ELF(elf_ex)) 113 ret = 0; 114 } 115 116 close(fd); 117 return (ret); 118 } 119 120 void 121 elf_loadkernel(char *file) 122 { 123 int fd; 124 125 if ((fd = open(file, O_RDONLY | O_EXLOCK, 0)) < 0) 126 err(1, "%s", file); 127 128 if (read(fd, (char *)&elf_ex, sizeof(elf_ex)) != sizeof(elf_ex)) 129 errx(1, "can't read elf header"); 130 131 if (!IS_ELF(elf_ex)) 132 errx(1, "bad elf magic"); 133 134 elf_size = lseek(fd, (off_t)0, SEEK_END); 135 (void)lseek(fd, (off_t)0, SEEK_SET); 136 elf_total = emalloc((size_t)elf_size); 137 138 if (read(fd, elf_total, (size_t)elf_size) != elf_size) 139 errx(1, "can't read elf kernel"); 140 141 if (elf_ex.e_phoff > (size_t)elf_size) 142 errx(1, "incorrect ELF header or truncated file"); 143 if (elf_ex.e_shoff > (size_t)elf_size) 144 errx(1, "incorrect ELF header or truncated file"); 145 146 elf_phdr = (Elf_Phdr *)&elf_total[elf_ex.e_phoff]; 147 elf_shdr = (Elf_Shdr *)&elf_total[elf_ex.e_shoff]; 148 149 if ((char *)&elf_shdr[elf_ex.e_shstrndx] + 150 sizeof(elf_shdr[elf_ex.e_shstrndx]) >= elf_total + (size_t)elf_size) 151 errx(1, "incorrect ELF header or truncated file"); 152 153 if ((char *)&elf_shdr[elf_ex.e_shstrndx].sh_offset + 154 sizeof(elf_shdr[elf_ex.e_shstrndx].sh_offset) >= 155 elf_total + (size_t)elf_size) 156 errx(1, "incorrect ELF header or truncated file"); 157 158 elf_shstrtab = &elf_total[elf_shdr[elf_ex.e_shstrndx].sh_offset]; 159 160 close(fd); 161 } 162 163 void 164 elf_savekernel(char *outfile) 165 { 166 int fd; 167 168 if ((fd = open(outfile, O_WRONLY | O_CREAT | O_TRUNC, 0755)) < 0) 169 err(1, "%s", outfile); 170 171 if (write(fd, elf_total, (size_t)elf_size) != elf_size) 172 errx(1, "can't write file %s", outfile); 173 174 close(fd); 175 } 176