| 1 | /* |
| 2 | * seama.c |
| 3 | * |
| 4 | * Copyright (C) 2011-2012 Gabor Juhos <juhosg@openwrt.org> |
| 5 | * |
| 6 | * Based on the trx fixup code: |
| 7 | * Copyright (C) 2005 Mike Baker |
| 8 | * Copyright (C) 2008 Felix Fietkau <nbd@openwrt.org> |
| 9 | * |
| 10 | * This program is free software; you can redistribute it and/or |
| 11 | * modify it under the terms of the GNU General Public License |
| 12 | * as published by the Free Software Foundation; either version 2 |
| 13 | * of the License, or (at your option) any later version. |
| 14 | * |
| 15 | * This program is distributed in the hope that it will be useful, |
| 16 | * but WITHOUT ANY WARRANTY; without even the implied warranty of |
| 17 | * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the |
| 18 | * GNU General Public License for more details. |
| 19 | * |
| 20 | * You should have received a copy of the GNU General Public License |
| 21 | * along with this program; if not, write to the Free Software |
| 22 | * Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA 02111-1307, USA. |
| 23 | */ |
| 24 | |
| 25 | #include <stdio.h> |
| 26 | #include <stdlib.h> |
| 27 | #include <stddef.h> |
| 28 | #include <unistd.h> |
| 29 | #include <fcntl.h> |
| 30 | #include <sys/mman.h> |
| 31 | #include <sys/stat.h> |
| 32 | #include <string.h> |
| 33 | #include <errno.h> |
| 34 | #include <arpa/inet.h> |
| 35 | |
| 36 | #include <sys/ioctl.h> |
| 37 | #include <mtd/mtd-user.h> |
| 38 | #include "mtd.h" |
| 39 | #include "seama.h" |
| 40 | #include "md5.h" |
| 41 | |
| 42 | #if __BYTE_ORDER == __BIG_ENDIAN |
| 43 | #define STORE32_LE(X) ((((X) & 0x000000FF) << 24) | (((X) & 0x0000FF00) << 8) | (((X) & 0x00FF0000) >> 8) | (((X) & 0xFF000000) >> 24)) |
| 44 | #elif __BYTE_ORDER == __LITTLE_ENDIAN |
| 45 | #define STORE32_LE(X) (X) |
| 46 | #else |
| 47 | #error unknown endianness! |
| 48 | #endif |
| 49 | |
| 50 | ssize_t pread(int fd, void *buf, size_t count, off_t offset); |
| 51 | ssize_t pwrite(int fd, const void *buf, size_t count, off_t offset); |
| 52 | |
| 53 | int |
| 54 | seama_fix_md5(char *buf, size_t len) |
| 55 | { |
| 56 | struct seama_hdr *shdr; |
| 57 | char *data; |
| 58 | size_t msize; |
| 59 | size_t isize; |
| 60 | MD5_CTX ctx; |
| 61 | unsigned char digest[16]; |
| 62 | int i; |
| 63 | |
| 64 | if (len < sizeof(struct seama_hdr)) |
| 65 | return -1; |
| 66 | |
| 67 | shdr = (struct seama_hdr *) buf; |
| 68 | if (shdr->magic != htonl(SEAMA_MAGIC)) { |
| 69 | fprintf(stderr, "no SEAMA header found\n"); |
| 70 | return -1; |
| 71 | } |
| 72 | |
| 73 | isize = ntohl(shdr->size); |
| 74 | msize = ntohs(shdr->metasize); |
| 75 | if (isize == 0) { |
| 76 | /* the image contains no checksum */ |
| 77 | return -1; |
| 78 | } |
| 79 | |
| 80 | len -= sizeof(struct seama_hdr) + sizeof(digest) + msize; |
| 81 | if (isize > len) |
| 82 | isize = len; |
| 83 | |
| 84 | data = buf + sizeof(struct seama_hdr) + sizeof(digest) + msize; |
| 85 | |
| 86 | MD5_Init(&ctx); |
| 87 | MD5_Update(&ctx, data, isize); |
| 88 | MD5_Final(digest, &ctx); |
| 89 | |
| 90 | if (!memcmp(digest, &buf[sizeof(struct seama_hdr)], sizeof(digest))) { |
| 91 | if (quiet < 2) |
| 92 | fprintf(stderr, "the header is fixed already\n"); |
| 93 | return -1; |
| 94 | } |
| 95 | |
| 96 | if (quiet < 2) { |
| 97 | fprintf(stderr, "new size:%u, new MD5: ", isize); |
| 98 | for (i = 0; i < sizeof(digest); i++) |
| 99 | fprintf(stderr, "%02x", digest[i]); |
| 100 | |
| 101 | fprintf(stderr, "\n"); |
| 102 | } |
| 103 | |
| 104 | /* update the size in the image */ |
| 105 | shdr->size = htonl(isize); |
| 106 | |
| 107 | /* update the checksum in the image */ |
| 108 | for (i = 0; i < sizeof(digest); i++) |
| 109 | buf[sizeof(struct seama_hdr) + i] = digest[i]; |
| 110 | |
| 111 | return 0; |
| 112 | } |
| 113 | |
| 114 | int |
| 115 | mtd_fixseama(const char *mtd, size_t offset) |
| 116 | { |
| 117 | int fd; |
| 118 | char *buf; |
| 119 | ssize_t res; |
| 120 | size_t block_offset; |
| 121 | |
| 122 | if (quiet < 2) |
| 123 | fprintf(stderr, "Trying to fix SEAMA header in %s at 0x%x...\n", |
| 124 | mtd, offset); |
| 125 | |
| 126 | block_offset = offset & ~(erasesize - 1); |
| 127 | offset -= block_offset; |
| 128 | |
| 129 | fd = mtd_check_open(mtd); |
| 130 | if(fd < 0) { |
| 131 | fprintf(stderr, "Could not open mtd device: %s\n", mtd); |
| 132 | exit(1); |
| 133 | } |
| 134 | |
| 135 | if (block_offset + erasesize > mtdsize) { |
| 136 | fprintf(stderr, "Offset too large, device size 0x%x\n", |
| 137 | mtdsize); |
| 138 | exit(1); |
| 139 | } |
| 140 | |
| 141 | buf = malloc(mtdsize); |
| 142 | if (!buf) { |
| 143 | perror("malloc"); |
| 144 | exit(1); |
| 145 | } |
| 146 | |
| 147 | res = pread(fd, buf, mtdsize, block_offset); |
| 148 | if (res != mtdsize) { |
| 149 | perror("pread"); |
| 150 | exit(1); |
| 151 | } |
| 152 | |
| 153 | if (seama_fix_md5(buf, mtdsize)) |
| 154 | goto out; |
| 155 | |
| 156 | if (mtd_erase_block(fd, block_offset)) { |
| 157 | fprintf(stderr, "Can't erease block at 0x%x (%s)\n", |
| 158 | block_offset, strerror(errno)); |
| 159 | exit(1); |
| 160 | } |
| 161 | |
| 162 | if (quiet < 2) |
| 163 | fprintf(stderr, "Rewriting block at 0x%x\n", block_offset); |
| 164 | |
| 165 | if (pwrite(fd, buf, erasesize, block_offset) != erasesize) { |
| 166 | fprintf(stderr, "Error writing block (%s)\n", strerror(errno)); |
| 167 | exit(1); |
| 168 | } |
| 169 | |
| 170 | if (quiet < 2) |
| 171 | fprintf(stderr, "Done.\n"); |
| 172 | |
| 173 | out: |
| 174 | close (fd); |
| 175 | sync(); |
| 176 | |
| 177 | return 0; |
| 178 | } |
| 179 | |
| 180 | |
