package/system/mtd/src/wrgg.c

   1 /*
   2  * wrgg.c
   3  *
   4  * Copyright (C) 2005 Mike Baker
   5  * Copyright (C) 2008 Felix Fietkau <nbd@nbd.name>
   6  * Copyright (C) 2011-2012 Gabor Juhos <juhosg@openwrt.org>
   7  * Copyright (C) 2016 Stijn Tintel <stijn@linux-ipv6.be>
   8  *
   9  * This program is free software; you can redistribute it and/or
  10  * modify it under the terms of the GNU General Public License
  11  * as published by the Free Software Foundation; either version 2
  12  * of the License, or (at your option) any later version.
  13  *
  14  * This program is distributed in the hope that it will be useful,
  15  * but WITHOUT ANY WARRANTY; without even the implied warranty of
  16  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  17  * GNU General Public License for more details.
  18  *
  19  * You should have received a copy of the GNU General Public License
  20  * along with this program; if not, write to the Free Software
  21  * Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA  02111-1307, USA.
  22  */
  23
  24 #include <endian.h>
  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 "wrgg.h"
  40 #include "md5.h"
  41
  42 static inline uint32_t le32_to_cpu(uint8_t *buf)
  43 {
  44         return buf[0] | buf[1] << 8 | buf[2] << 16 | buf[3] << 24;
  45 }
  46
  47 ssize_t pread(int fd, void *buf, size_t count, off_t offset);
  48 ssize_t pwrite(int fd, const void *buf, size_t count, off_t offset);
  49
  50 int
  51 wrgg_fix_md5(struct wrgg03_header *shdr, int fd, size_t data_offset, size_t data_size)
  52 {
  53         char *buf;
  54         ssize_t res;
  55         MD5_CTX ctx;
  56         unsigned char digest[16];
  57         int i;
  58         int err = 0;
  59
  60         buf = malloc(data_size);
  61         if (!buf) {
  62                 err = -ENOMEM;
  63                 goto err_out;
  64         }
  65
  66         res = pread(fd, buf, data_size, data_offset);
  67         if (res != data_size) {
  68                 perror("pread");
  69                 err = -EIO;
  70                 goto err_free;
  71         }
  72
  73         MD5_Init(&ctx);
  74         MD5_Update(&ctx, (char *)&shdr->offset, sizeof(shdr->offset));
  75         MD5_Update(&ctx, (char *)&shdr->dev_name, sizeof(shdr->dev_name));
  76         MD5_Update(&ctx, buf, data_size);
  77         MD5_Final(digest, &ctx);
  78
  79         if (!memcmp(digest, shdr->digest, sizeof(digest))) {
  80                 if (quiet < 2)
  81                         fprintf(stderr, "the header is fixed already\n");
  82                 return -1;
  83         }
  84
  85         if (quiet < 2) {
  86                 fprintf(stderr, "new size:%u, new MD5: ", data_size);
  87                 for (i = 0; i < sizeof(digest); i++)
  88                         fprintf(stderr, "%02x", digest[i]);
  89
  90                 fprintf(stderr, "\n");
  91         }
  92
  93         /* update the size in the image */
  94         shdr->size = data_size;
  95
  96         /* update the checksum in the image */
  97         memcpy(shdr->digest, digest, sizeof(digest));
  98
  99 err_free:
 100         free(buf);
 101 err_out:
 102         return err;
 103 }
 104
 105 int
 106 mtd_fixwrgg(const char *mtd, size_t offset, size_t data_size)
 107 {
 108         int fd;
 109         char *first_block;
 110         ssize_t res;
 111         size_t block_offset;
 112         size_t data_offset;
 113         struct wrgg03_header *shdr;
 114
 115         if (quiet < 2)
 116                 fprintf(stderr, "Trying to fix WRGG header in %s at 0x%x...\n",
 117                         mtd, offset);
 118
 119         block_offset = offset & ~(erasesize - 1);
 120         offset -= block_offset;
 121
 122         fd = mtd_check_open(mtd);
 123         if(fd < 0) {
 124                 fprintf(stderr, "Could not open mtd device: %s\n", mtd);
 125                 exit(1);
 126         }
 127
 128         if (block_offset + erasesize > mtdsize) {
 129                 fprintf(stderr, "Offset too large, device size 0x%x\n",
 130                         mtdsize);
 131                 exit(1);
 132         }
 133
 134         first_block = malloc(erasesize);
 135         if (!first_block) {
 136                 perror("malloc");
 137                 exit(1);
 138         }
 139
 140         res = pread(fd, first_block, erasesize, block_offset);
 141         if (res != erasesize) {
 142                 perror("pread");
 143                 exit(1);
 144         }
 145
 146         shdr = (struct wrgg03_header *)(first_block + offset);
 147
 148         /* The magic is always stored in little-endian byte order */
 149         if (le32_to_cpu((uint8_t *)&shdr->magic1) != WRGG03_MAGIC) {
 150                 fprintf(stderr, "magic1 = %x\n", shdr->magic1);
 151                 fprintf(stderr, "WRGG03_MAGIC = %x\n", WRGG03_MAGIC);
 152                 fprintf(stderr, "No WRGG header found\n");
 153                 exit(1);
 154         } else if (!shdr->size) {
 155                 fprintf(stderr, "WRGG entity with empty image\n");
 156                 exit(1);
 157         }
 158
 159         data_offset = offset + sizeof(struct wrgg03_header);
 160         if (!data_size)
 161                 data_size = mtdsize - data_offset;
 162         if (data_size > shdr->size)
 163                 data_size = shdr->size;
 164         if (wrgg_fix_md5(shdr, fd, data_offset, data_size))
 165                 goto out;
 166
 167         if (mtd_erase_block(fd, block_offset)) {
 168                 fprintf(stderr, "Can't erease block at 0x%x (%s)\n",
 169                         block_offset, strerror(errno));
 170                 exit(1);
 171         }
 172
 173         if (quiet < 2)
 174                 fprintf(stderr, "Rewriting block at 0x%x\n", block_offset);
 175
 176         if (pwrite(fd, first_block, erasesize, block_offset) != erasesize) {
 177                 fprintf(stderr, "Error writing block (%s)\n", strerror(errno));
 178                 exit(1);
 179         }
 180
 181         if (quiet < 2)
 182                 fprintf(stderr, "Done.\n");
 183
 184 out:
 185         close (fd);
 186         sync();
 187
 188         return 0;
 189 }