OpenWrt – Rev 4
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/*
* osafeloader
*
* Copyright (C) 2016 Rafał Miłecki <zajec5@gmail.com>
*
* This program is free software; you can redistribute it and/or modify
* it under the terms of the GNU General Public License version 2 as
* published by the Free Software Foundation.
*/
#include <byteswap.h>
#include <endian.h>
#include <errno.h>
#include <stdint.h>
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <unistd.h>
#include "md5.h"
#if !defined(__BYTE_ORDER)
#error "Unknown byte order"
#endif
#if __BYTE_ORDER == __BIG_ENDIAN
#define cpu_to_be32(x) (x)
#define be32_to_cpu(x) (x)
#define cpu_to_be16(x) (x)
#define be16_to_cpu(x) (x)
#elif __BYTE_ORDER == __LITTLE_ENDIAN
#define cpu_to_be32(x) bswap_32(x)
#define be32_to_cpu(x) bswap_32(x)
#define cpu_to_be16(x) bswap_16(x)
#define be16_to_cpu(x) bswap_16(x)
#else
#error "Unsupported endianness"
#endif
struct safeloader_header {
uint32_t imagesize;
uint8_t md5[16];
} __attribute__ ((packed));
char *safeloader_path;
char *partition_name;
char *out_path;
static inline size_t osafeloader_min(size_t x, size_t y) {
return x < y ? x : y;
}
static const uint8_t md5_salt[16] = {
0x7a, 0x2b, 0x15, 0xed,
0x9b, 0x98, 0x59, 0x6d,
0xe5, 0x04, 0xab, 0x44,
0xac, 0x2a, 0x9f, 0x4e,
};
/**************************************************
* Info
**************************************************/
static int osafeloader_info(int argc, char **argv) {
FILE *safeloader;
struct safeloader_header hdr;
MD5_CTX ctx;
size_t bytes, imagesize;
uint8_t buf[1024];
uint8_t md5[16];
char name[32];
int base, size, i;
int err = 0;
if (argc < 3) {
fprintf(stderr, "No SafeLoader file passed\n");
err = -EINVAL;
goto out;
}
safeloader_path = argv[2];
safeloader = fopen(safeloader_path, "r");
if (!safeloader) {
fprintf(stderr, "Couldn't open %s\n", safeloader_path);
err = -EACCES;
goto out;
}
bytes = fread(&hdr, 1, sizeof(hdr), safeloader);
if (bytes != sizeof(hdr)) {
fprintf(stderr, "Couldn't read %s header\n", safeloader_path);
err = -EIO;
goto err_close;
}
imagesize = be32_to_cpu(hdr.imagesize);
MD5_Init(&ctx);
MD5_Update(&ctx, md5_salt, sizeof(md5_salt));
while ((bytes = fread(buf, 1, osafeloader_min(sizeof(buf), imagesize), safeloader)) > 0) {
MD5_Update(&ctx, buf, bytes);
imagesize -= bytes;
}
MD5_Final(md5, &ctx);
if (memcmp(md5, hdr.md5, 16)) {
fprintf(stderr, "Broken SafeLoader file with invalid MD5\n");
err = -EIO;
goto err_close;
}
printf("%10s: %d\n", "Image size", be32_to_cpu(hdr.imagesize));
printf("%10s: ", "MD5");
for (i = 0; i < 16; i++)
printf("%02x", md5[i]);
printf("\n");
/* Skip header & vendor info */
fseek(safeloader, 0x1014, SEEK_SET);
while (fscanf(safeloader, "fwup-ptn %s base 0x%x size 0x%x\t\r\n", name, &base, &size) == 3) {
printf("%10s: %s (0x%x - 0x%x)\n", "Partition", name, base, base + size);
}
err_close:
fclose(safeloader);
out:
return err;
}
/**************************************************
* Extract
**************************************************/
static void osafeloader_extract_parse_options(int argc, char **argv) {
int c;
while ((c = getopt(argc, argv, "p:o:")) != -1) {
switch (c) {
case 'p':
partition_name = optarg;
break;
case 'o':
out_path = optarg;
break;
}
}
}
static int osafeloader_extract(int argc, char **argv) {
FILE *safeloader;
FILE *out;
struct safeloader_header hdr;
size_t bytes;
char name[32];
int base, size;
int err = 0;
if (argc < 3) {
fprintf(stderr, "No SafeLoader file passed\n");
err = -EINVAL;
goto out;
}
safeloader_path = argv[2];
optind = 3;
osafeloader_extract_parse_options(argc, argv);
if (!partition_name) {
fprintf(stderr, "No partition name specified\n");
err = -EINVAL;
goto out;
} else if (!out_path) {
fprintf(stderr, "No output file specified\n");
err = -EINVAL;
goto out;
}
safeloader = fopen(safeloader_path, "r");
if (!safeloader) {
fprintf(stderr, "Couldn't open %s\n", safeloader_path);
err = -EACCES;
goto out;
}
out = fopen(out_path, "w");
if (!out) {
fprintf(stderr, "Couldn't open %s\n", out_path);
err = -EACCES;
goto err_close_safeloader;
}
bytes = fread(&hdr, 1, sizeof(hdr), safeloader);
if (bytes != sizeof(hdr)) {
fprintf(stderr, "Couldn't read %s header\n", safeloader_path);
err = -EIO;
goto err_close_out;
}
/* Skip vendor info */
fseek(safeloader, 0x1000, SEEK_CUR);
err = -ENOENT;
while (fscanf(safeloader, "fwup-ptn %s base 0x%x size 0x%x\t\r\n", name, &base, &size) == 3) {
uint8_t buf[1024];
if (strcmp(name, partition_name))
continue;
err = 0;
fseek(safeloader, sizeof(hdr) + 0x1000 + base, SEEK_SET);
while ((bytes = fread(buf, 1, osafeloader_min(sizeof(buf), size), safeloader)) > 0) {
if (fwrite(buf, 1, bytes, out) != bytes) {
fprintf(stderr, "Couldn't write %zu B to %s\n", bytes, out_path);
err = -EIO;
break;
}
size -= bytes;
}
if (size) {
fprintf(stderr, "Couldn't extract whole partition %s from %s (%d B left)\n", partition_name, safeloader_path, size);
err = -EIO;
}
break;
}
err_close_out:
fclose(out);
err_close_safeloader:
fclose(safeloader);
out:
return err;
}
/**************************************************
* Start
**************************************************/
static void usage() {
printf("Usage:\n");
printf("\n");
printf("Info about SafeLoader:\n");
printf("\tosafeloader info <file>\n");
printf("\n");
printf("Extract from SafeLoader:\n");
printf("\tosafeloader extract <file> [options]\n");
printf("\t-p name\t\t\t\tname of partition to extract\n");
printf("\t-o file\t\t\t\toutput file\n");
}
int main(int argc, char **argv) {
if (argc > 1) {
if (!strcmp(argv[1], "info"))
return osafeloader_info(argc, argv);
else if (!strcmp(argv[1], "extract"))
return osafeloader_extract(argc, argv);
}
usage();
return 0;
}