tplink-safeloader: add support to split & extract firmwares

Split the oem firmware upgrade images into seperate files.
Useful when analysing oem firmware files.

Signed-off-by: Alexander Couzens <lynxis@fe80.eu>
This commit is contained in:
Alexander Couzens 2018-03-02 00:44:30 +01:00
parent 0c7e78930b
commit 638e2193fe

View File

@ -46,6 +46,7 @@
#include <sys/types.h>
#include <sys/stat.h>
#include <limits.h>
#include "md5.h"
@ -1379,6 +1380,9 @@ static void usage(const char *argv0) {
"Usage: %s [OPTIONS...]\n"
"\n"
"Options:\n"
" -h show this help\n"
"\n"
"Create a new image:\n"
" -B <board> create image for the board specified with <board>\n"
" -k <file> read kernel image from the file <file>\n"
" -r <file> read rootfs image from the file <file>\n"
@ -1386,7 +1390,9 @@ static void usage(const char *argv0) {
" -V <rev> sets the revision number to <rev>\n"
" -j add jffs2 end-of-filesystem markers\n"
" -S create sysupgrade instead of factory image\n"
" -h show this help\n",
"Extract an old image:\n"
" -x <file> extract all oem firmware partition\n"
" -d <dir> destination to extract the firmware partition\n",
argv0
);
};
@ -1403,8 +1409,232 @@ static const struct device_info *find_board(const char *id)
return NULL;
}
static int add_flash_partition(
struct flash_partition_entry *part_list,
size_t max_entries,
const char *name,
unsigned long base,
unsigned long size)
{
int ptr = 0;
/* check if the list has a free entry */
for (int ptr=0; ptr<max_entries; ptr++, part_list++) {
if (part_list->name == NULL &&
part_list->base == 0 &&
part_list->size == 0)
break;
}
if (ptr == max_entries) {
error(1, 0, "No free flash part entry available.");
}
part_list->name = calloc(1, strlen(name) + 1);
memcpy((char *)part_list->name, name, strlen(name));
part_list->base = base;
part_list->size = size;
return 0;
}
/** read the partition table into struct flash_partition_entry */
static int read_partition_table(
FILE *file, long offset,
struct flash_partition_entry *entries, size_t max_entries,
int type)
{
char buf[2048];
char *ptr, *end;
const char *parthdr = NULL;
const char *fwuphdr = "fwup-ptn";
const char *flashhdr = "partition";
/* TODO: search for the partition table */
switch(type) {
case 0:
parthdr = fwuphdr;
break;
case 1:
parthdr = flashhdr;
break;
default:
error(1, 0, "Invalid partition table");
}
if (fseek(file, offset, SEEK_SET) < 0)
error(1, errno, "Can not seek in the firmware");
if (fread(buf, 1, 2048, file) < 0)
error(1, errno, "Can not read fwup-ptn from the firmware");
buf[2047] = '\0';
/* look for the partition header */
if (memcmp(buf, parthdr, strlen(parthdr)) != 0) {
fprintf(stderr, "DEBUG: can not find fwuphdr\n");
return 1;
}
ptr = buf;
end = buf + sizeof(buf);
while ((ptr + strlen(parthdr)) < end &&
memcmp(ptr, parthdr, strlen(parthdr)) == 0) {
char *end_part;
char *end_element;
char name[32] = { 0 };
int name_len = 0;
unsigned long base = 0;
unsigned long size = 0;
end_part = memchr(ptr, '\n', (end - ptr));
if (end_part == NULL) {
/* in theory this should never happen, because a partition always ends with 0x09, 0x0D, 0x0A */
break;
}
for (int i=0; i<=4; i++) {
if (end_part <= ptr)
break;
end_element = memchr(ptr, 0x20, (end_part - ptr));
if (end_element == NULL) {
error(1, errno, "Ignoring the rest of the partition entries.");
break;
}
switch (i) {
/* partition header */
case 0:
ptr = end_element + 1;
continue;
/* name */
case 1:
name_len = (end_element - ptr) > 31 ? 31 : (end_element - ptr);
strncpy(name, ptr, name_len);
name[name_len] = '\0';
ptr = end_element + 1;
continue;
/* string "base" */
case 2:
ptr = end_element + 1;
continue;
/* actual base */
case 3:
base = strtoul(ptr, NULL, 16);
ptr = end_element + 1;
continue;
/* string "size" */
case 4:
ptr = end_element + 1;
/* actual size. The last element doesn't have a sepeartor */
size = strtoul(ptr, NULL, 16);
/* the part ends with 0x09, 0x0d, 0x0a */
ptr = end_part + 1;
add_flash_partition(entries, max_entries, name, base, size);
continue;
}
}
}
return 0;
}
static void write_partition(
FILE *input_file,
size_t firmware_offset,
struct flash_partition_entry *entry,
FILE *output_file)
{
char buf[4096];
size_t offset;
fseek(input_file, entry->base + firmware_offset, SEEK_SET);
for (offset = 0; sizeof(buf) + offset <= entry->size; offset += sizeof(buf)) {
if (fread(buf, sizeof(buf), 1, input_file) < 0)
error(1, errno, "Can not read partition from input_file");
if (fwrite(buf, sizeof(buf), 1, output_file) < 0)
error(1, errno, "Can not write partition to output_file");
}
/* write last chunk smaller than buffer */
if (offset < entry->size) {
offset = entry->size - offset;
if (fread(buf, offset, 1, input_file) < 0)
error(1, errno, "Can not read partition from input_file");
if (fwrite(buf, offset, 1, output_file) < 0)
error(1, errno, "Can not write partition to output_file");
}
}
static int extract_firmware_partition(FILE *input_file, size_t firmware_offset, struct flash_partition_entry *entry, const char *output_directory)
{
FILE *output_file;
char output[PATH_MAX];
snprintf(output, PATH_MAX, "%s/%s", output_directory, entry->name);
output_file = fopen(output, "wb+");
if (output_file == NULL) {
error(1, errno, "Can not open output file %s", output);
}
write_partition(input_file, firmware_offset, entry, output_file);
fclose(output_file);
return 0;
}
/** extract all partitions from the firmware file */
static int extract_firmware(const char *input, const char *output_directory)
{
struct flash_partition_entry entries[16] = { 0 };
size_t max_entries = 16;
size_t firmware_offset = 0x1014;
FILE *input_file;
struct stat statbuf;
/* check input file */
if (stat(input, &statbuf)) {
error(1, errno, "Can not read input firmware %s", input);
}
/* check if output directory exists */
if (stat(output_directory, &statbuf)) {
error(1, errno, "Failed to stat output directory %s", output_directory);
}
if ((statbuf.st_mode & S_IFMT) != S_IFDIR) {
error(1, errno, "Given output directory is not a directory %s", output_directory);
}
input_file = fopen(input, "rb");
if (read_partition_table(input_file, firmware_offset, entries, 16, 0) != 0) {
error(1, 0, "Error can not read the partition table (fwup-ptn)");
}
for (int i=0; i<max_entries; i++) {
if (entries[i].name == NULL &&
entries[i].base == 0 &&
entries[i].size == 0)
continue;
extract_firmware_partition(input_file, firmware_offset, &entries[i], output_directory);
}
return 0;
}
int main(int argc, char *argv[]) {
const char *board = NULL, *kernel_image = NULL, *rootfs_image = NULL, *output = NULL;
const char *extract_image = NULL, *output_directory = NULL;
bool add_jffs2_eof = false, sysupgrade = false;
unsigned rev = 0;
const struct device_info *info;
@ -1413,7 +1643,7 @@ int main(int argc, char *argv[]) {
while (true) {
int c;
c = getopt(argc, argv, "B:k:r:o:V:jSh");
c = getopt(argc, argv, "B:k:r:o:V:jSh:x:d:");
if (c == -1)
break;
@ -1450,12 +1680,27 @@ int main(int argc, char *argv[]) {
usage(argv[0]);
return 0;
case 'd':
output_directory = optarg;
break;
case 'x':
extract_image = optarg;
break;
default:
usage(argv[0]);
return 1;
}
}
if (extract_image || output_directory) {
if (!extract_image)
error(1, 0, "No factory/oem image given via -x <file>. Output directory is only valid with -x");
if (!output_directory)
error(1, 0, "Can not extract an image without output directory. Use -d <dir>");
extract_firmware(extract_image, output_directory);
} else {
if (!board)
error(1, 0, "no board has been specified");
if (!kernel_image)
@ -1471,6 +1716,7 @@ int main(int argc, char *argv[]) {
error(1, 0, "unsupported board %s", board);
build_image(output, kernel_image, rootfs_image, rev, add_jffs2_eof, sysupgrade, info);
}
return 0;
}