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 #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 wrgg_fix_md5(struct wrgg03_header *shdr, int fd, size_t data_offset, size_t data_size)
  55 {
  56         char *buf;
  57         ssize_t res;
  58         MD5_CTX ctx;
  59         unsigned char digest[16];
  60         int i;
  61         int err = 0;
  62
  63         buf = malloc(data_size);
  64         if (!buf) {
  65                 err = -ENOMEM;
  66                 goto err_out;
  67         }
  68
  69         res = pread(fd, buf, data_size, data_offset);
  70         if (res != data_size) {
  71                 perror("pread");
  72                 err = -EIO;
  73                 goto err_free;
  74         }
  75
  76         MD5_Init(&ctx);
  77         MD5_Update(&ctx, (char *)&shdr->offset, sizeof(shdr->offset));
  78         MD5_Update(&ctx, (char *)&shdr->dev_name, sizeof(shdr->dev_name));
  79         MD5_Update(&ctx, buf, data_size);
  80         MD5_Final(digest, &ctx);
  81
  82         if (!memcmp(digest, shdr->digest, sizeof(digest))) {
  83                 if (quiet < 2)
  84                         fprintf(stderr, "the header is fixed already\n");
  85                 return -1;
  86         }
  87
  88         if (quiet < 2) {
  89                 fprintf(stderr, "new size:%u, new MD5: ", data_size);
  90                 for (i = 0; i < sizeof(digest); i++)
  91                         fprintf(stderr, "%02x", digest[i]);
  92
  93                 fprintf(stderr, "\n");
  94         }
  95
  96         /* update the size in the image */
  97         shdr->size = htonl(data_size);
  98
  99         /* update the checksum in the image */
 100         memcpy(shdr->digest, digest, sizeof(digest));
 101
 102 err_free:
 103         free(buf);
 104 err_out:
 105         return err;
 106 }
 107
 108 int
 109 mtd_fixwrgg(const char *mtd, size_t offset, size_t data_size)
 110 {
 111         int fd;
 112         char *first_block;
 113         ssize_t res;
 114         size_t block_offset;
 115         size_t data_offset;
 116         struct wrgg03_header *shdr;
 117
 118         if (quiet < 2)
 119                 fprintf(stderr, "Trying to fix WRGG header in %s at 0x%x...\n",
 120                         mtd, offset);
 121
 122         block_offset = offset & ~(erasesize - 1);
 123         offset -= block_offset;
 124
 125         fd = mtd_check_open(mtd);
 126         if(fd < 0) {
 127                 fprintf(stderr, "Could not open mtd device: %s\n", mtd);
 128                 exit(1);
 129         }
 130
 131         if (block_offset + erasesize > mtdsize) {
 132                 fprintf(stderr, "Offset too large, device size 0x%x\n",
 133                         mtdsize);
 134                 exit(1);
 135         }
 136
 137         first_block = malloc(erasesize);
 138         if (!first_block) {
 139                 perror("malloc");
 140                 exit(1);
 141         }
 142
 143         res = pread(fd, first_block, erasesize, block_offset);
 144         if (res != erasesize) {
 145                 perror("pread");
 146                 exit(1);
 147         }
 148
 149         shdr = (struct wrgg03_header *)(first_block + offset);
 150         if (shdr->magic1 != htonl(STORE32_LE(WRGG03_MAGIC))) {
 151                 fprintf(stderr, "magic1 %x\n", shdr->magic1);
 152                 fprintf(stderr, "htonl(WRGG03_MAGIC) %x\n", WRGG03_MAGIC);
 153                 fprintf(stderr, "No WRGG header found\n");
 154                 exit(1);
 155         } else if (!ntohl(shdr->size)) {
 156                 fprintf(stderr, "WRGG entity with empty image\n");
 157                 exit(1);
 158         }
 159
 160         data_offset = offset + sizeof(struct wrgg03_header);
 161         if (!data_size)
 162                 data_size = mtdsize - data_offset;
 163         if (data_size > ntohl(shdr->size))
 164                 data_size = ntohl(shdr->size);
 165         if (wrgg_fix_md5(shdr, fd, data_offset, data_size))
 166                 goto out;
 167
 168         if (mtd_erase_block(fd, block_offset)) {
 169                 fprintf(stderr, "Can't erease block at 0x%x (%s)\n",
 170                         block_offset, strerror(errno));
 171                 exit(1);
 172         }
 173
 174         if (quiet < 2)
 175                 fprintf(stderr, "Rewriting block at 0x%x\n", block_offset);
 176
 177         if (pwrite(fd, first_block, erasesize, block_offset) != erasesize) {
 178                 fprintf(stderr, "Error writing block (%s)\n", strerror(errno));
 179                 exit(1);
 180         }
 181
 182         if (quiet < 2)
 183                 fprintf(stderr, "Done.\n");
 184
 185 out:
 186         close (fd);
 187         sync();
 188
 189         return 0;
 190 }