1 /* $OpenBSD: exec_elf.c,v 1.18 2021/10/24 21:24:18 deraadt 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 30 #include <elf.h> 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 #include "exec.h" 42 43 caddr_t ptr, rest, pre; 44 Elf_Ehdr elf_ex; 45 Elf_Phdr *elf_phdr; 46 Elf_Shdr *elf_shdr; 47 char *elf_total; 48 char *elf_shstrtab; 49 off_t elf_size; 50 51 caddr_t 52 adjust(caddr_t x) 53 { 54 int i; 55 Elf_Shdr *s; 56 unsigned long y = 0; 57 58 s = elf_shdr; 59 60 for (i = 0; i < elf_ex.e_shnum; i++) { 61 if (s[i].sh_addr == 0) 62 continue; 63 if (((unsigned long)x >= s[i].sh_addr) && 64 ((unsigned long)x < (s[i].sh_addr+s[i].sh_size))) { 65 y = (unsigned long)&elf_total[(unsigned long)x - 66 s[i].sh_addr + s[i].sh_offset]; 67 break; 68 } 69 } 70 71 return((caddr_t)y); 72 } 73 74 caddr_t 75 readjust(caddr_t x) 76 { 77 int i; 78 Elf_Shdr *s; 79 unsigned long y = 0; 80 81 s = elf_shdr; 82 83 for (i = 0; i < elf_ex.e_shnum; i++) { 84 if (s[i].sh_addr == 0) 85 continue; 86 if (((x - elf_total) >= s[i].sh_offset) && 87 ((x - elf_total) <= (s[i].sh_offset + s[i].sh_size))) 88 y = (unsigned long)x - (unsigned long)elf_total + 89 (unsigned long)s[i].sh_addr - s[i].sh_offset; 90 } 91 92 return((caddr_t)y); 93 } 94 95 void 96 loadkernel(char *file) 97 { 98 int fd; 99 100 if ((fd = open(file, O_RDONLY | O_EXLOCK)) == -1) 101 err(1, "%s", file); 102 103 if (read(fd, (char *)&elf_ex, sizeof(elf_ex)) != sizeof(elf_ex)) 104 errx(1, "can't read elf header"); 105 106 if (!IS_ELF(elf_ex)) 107 errx(1, "bad elf magic"); 108 109 elf_size = lseek(fd, (off_t)0, SEEK_END); 110 (void)lseek(fd, (off_t)0, SEEK_SET); 111 elf_total = emalloc((size_t)elf_size); 112 113 if (read(fd, elf_total, (size_t)elf_size) != elf_size) 114 errx(1, "can't read elf kernel"); 115 116 if (elf_ex.e_phoff > (size_t)elf_size) 117 errx(1, "incorrect ELF header or truncated file"); 118 if (elf_ex.e_shoff > (size_t)elf_size) 119 errx(1, "incorrect ELF header or truncated file"); 120 121 elf_phdr = (Elf_Phdr *)&elf_total[elf_ex.e_phoff]; 122 elf_shdr = (Elf_Shdr *)&elf_total[elf_ex.e_shoff]; 123 124 if ((char *)&elf_shdr[elf_ex.e_shstrndx] + 125 sizeof(elf_shdr[elf_ex.e_shstrndx]) >= elf_total + (size_t)elf_size) 126 errx(1, "incorrect ELF header or truncated file"); 127 128 if ((char *)&elf_shdr[elf_ex.e_shstrndx].sh_offset + 129 sizeof(elf_shdr[elf_ex.e_shstrndx].sh_offset) >= 130 elf_total + (size_t)elf_size) 131 errx(1, "incorrect ELF header or truncated file"); 132 133 elf_shstrtab = &elf_total[elf_shdr[elf_ex.e_shstrndx].sh_offset]; 134 135 close(fd); 136 } 137 138 void 139 savekernel(char *outfile) 140 { 141 int fd; 142 143 if ((fd = open(outfile, O_WRONLY | O_CREAT | O_TRUNC, 0700)) == -1) 144 err(1, "%s", outfile); 145 146 if (write(fd, elf_total, (size_t)elf_size) != elf_size) 147 errx(1, "can't write file %s", outfile); 148 149 close(fd); 150 } 151