OpenWrt – Rev 4
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/*
* wrgg.c
*
* Copyright (C) 2005 Mike Baker
* Copyright (C) 2008 Felix Fietkau <nbd@nbd.name>
* Copyright (C) 2011-2012 Gabor Juhos <juhosg@openwrt.org>
* Copyright (C) 2016 Stijn Tintel <stijn@linux-ipv6.be>
*
* This program is free software; you can redistribute it and/or
* modify it under the terms of the GNU General Public License
* as published by the Free Software Foundation; either version 2
* of the License, or (at your option) any later version.
*
* This program is distributed in the hope that it will be useful,
* but WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
* GNU General Public License for more details.
*
* You should have received a copy of the GNU General Public License
* along with this program; if not, write to the Free Software
* Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA 02111-1307, USA.
*/
#include <endian.h>
#include <stdio.h>
#include <stdlib.h>
#include <stddef.h>
#include <unistd.h>
#include <fcntl.h>
#include <sys/mman.h>
#include <sys/stat.h>
#include <string.h>
#include <errno.h>
#include <arpa/inet.h>
#include <sys/ioctl.h>
#include <mtd/mtd-user.h>
#include "mtd.h"
#include "wrgg.h"
#include "md5.h"
#if __BYTE_ORDER == __BIG_ENDIAN
#define STORE32_LE(X) ((((X) & 0x000000FF) << 24) | (((X) & 0x0000FF00) << 8) | (((X) & 0x00FF0000) >> 8) | (((X) & 0xFF000000) >> 24))
#elif __BYTE_ORDER == __LITTLE_ENDIAN
#define STORE32_LE(X) (X)
#else
#error unknown endianness!
#endif
ssize_t pread(int fd, void *buf, size_t count, off_t offset);
ssize_t pwrite(int fd, const void *buf, size_t count, off_t offset);
int
wrgg_fix_md5(struct wrgg03_header *shdr, int fd, size_t data_offset, size_t data_size)
{
char *buf;
ssize_t res;
MD5_CTX ctx;
unsigned char digest[16];
int i;
int err = 0;
buf = malloc(data_size);
if (!buf) {
err = -ENOMEM;
goto err_out;
}
res = pread(fd, buf, data_size, data_offset);
if (res != data_size) {
perror("pread");
err = -EIO;
goto err_free;
}
MD5_Init(&ctx);
MD5_Update(&ctx, (char *)&shdr->offset, sizeof(shdr->offset));
MD5_Update(&ctx, (char *)&shdr->dev_name, sizeof(shdr->dev_name));
MD5_Update(&ctx, buf, data_size);
MD5_Final(digest, &ctx);
if (!memcmp(digest, shdr->digest, sizeof(digest))) {
if (quiet < 2)
fprintf(stderr, "the header is fixed already\n");
return -1;
}
if (quiet < 2) {
fprintf(stderr, "new size:%u, new MD5: ", data_size);
for (i = 0; i < sizeof(digest); i++)
fprintf(stderr, "%02x", digest[i]);
fprintf(stderr, "\n");
}
/* update the size in the image */
shdr->size = htonl(data_size);
/* update the checksum in the image */
memcpy(shdr->digest, digest, sizeof(digest));
err_free:
free(buf);
err_out:
return err;
}
int
mtd_fixwrgg(const char *mtd, size_t offset, size_t data_size)
{
int fd;
char *first_block;
ssize_t res;
size_t block_offset;
size_t data_offset;
struct wrgg03_header *shdr;
if (quiet < 2)
fprintf(stderr, "Trying to fix WRGG header in %s at 0x%x...\n",
mtd, offset);
block_offset = offset & ~(erasesize - 1);
offset -= block_offset;
fd = mtd_check_open(mtd);
if(fd < 0) {
fprintf(stderr, "Could not open mtd device: %s\n", mtd);
exit(1);
}
if (block_offset + erasesize > mtdsize) {
fprintf(stderr, "Offset too large, device size 0x%x\n",
mtdsize);
exit(1);
}
first_block = malloc(erasesize);
if (!first_block) {
perror("malloc");
exit(1);
}
res = pread(fd, first_block, erasesize, block_offset);
if (res != erasesize) {
perror("pread");
exit(1);
}
shdr = (struct wrgg03_header *)(first_block + offset);
if (shdr->magic1 != htonl(STORE32_LE(WRGG03_MAGIC))) {
fprintf(stderr, "magic1 %x\n", shdr->magic1);
fprintf(stderr, "htonl(WRGG03_MAGIC) %x\n", WRGG03_MAGIC);
fprintf(stderr, "No WRGG header found\n");
exit(1);
} else if (!ntohl(shdr->size)) {
fprintf(stderr, "WRGG entity with empty image\n");
exit(1);
}
data_offset = offset + sizeof(struct wrgg03_header);
if (!data_size)
data_size = mtdsize - data_offset;
if (data_size > ntohl(shdr->size))
data_size = ntohl(shdr->size);
if (wrgg_fix_md5(shdr, fd, data_offset, data_size))
goto out;
if (mtd_erase_block(fd, block_offset)) {
fprintf(stderr, "Can't erease block at 0x%x (%s)\n",
block_offset, strerror(errno));
exit(1);
}
if (quiet < 2)
fprintf(stderr, "Rewriting block at 0x%x\n", block_offset);
if (pwrite(fd, first_block, erasesize, block_offset) != erasesize) {
fprintf(stderr, "Error writing block (%s)\n", strerror(errno));
exit(1);
}
if (quiet < 2)
fprintf(stderr, "Done.\n");
out:
close (fd);
sync();
return 0;
}