OpenWrt – Rev 2
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/*
* Copyright (C) 2013 Jeff Kent <jeff@jkent.net>
*
* 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.
*
* 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
*
* This tool encrypts and decrypts uImage formatted firmware for Hilink
* HLK-RM04 wireless modules. It will also truncate a dump of mtd6 and make
* it an image suitable for flashing via the stock firmware upgrade page.
*
* Build instructions:
* gcc -lcrypto hlkcrypt.c -o hlkcrypt
*/
#include <arpa/inet.h>
#include <errno.h>
#include <fcntl.h>
#include <getopt.h>
#include <openssl/des.h>
#include <stdint.h>
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <sys/mman.h>
#include <sys/types.h>
#include <sys/stat.h>
#include <unistd.h>
#define DES_KEY "H@L9K*(3"
#ifndef min
#define min(a,b) \
({ __typeof__ (a) _a = (a); \
__typeof__ (b) _b = (b); \
_a < _b ? _a : _b; })
#endif
#define IH_MAGIC 0x27051956
#define IH_NMLEN 32
typedef struct image_header {
uint32_t ih_magic; /* Image Header Magic Number */
uint32_t ih_hcrc; /* Image Header CRC Checksum */
uint32_t ih_time; /* Image Creation Timestamp */
uint32_t ih_size; /* Image Data Size */
uint32_t ih_load; /* Data Load Address */
uint32_t ih_ep; /* Entry Point Address */
uint32_t ih_dcrc; /* Image Data CRC Checksum */
uint8_t ih_os; /* Operating System */
uint8_t ih_arch; /* CPU architecture */
uint8_t ih_type; /* Image Type */
uint8_t ih_comp; /* Compression Type */
uint8_t ih_name[IH_NMLEN]; /* Image Name */
} image_header_t;
static int temp_fd = -1;
static DES_key_schedule schedule;
static void show_usage(const char *arg0);
static void exit_cleanup(void);
static void copy_file(int src, int dst);
static void do_encrypt(void *p, off_t len);
static void do_decrypt(void *p, off_t len);
int main(int argc, char **argv)
{
int encrypt_opt = 0;
int decrypt_opt = 0;
int input_opt = 0;
int output_opt = 0;
char *input_filename = NULL;
char *output_filename = NULL;
int input_fd;
int output_fd;
off_t file_len;
char *p;
char buf[sizeof(image_header_t) + 3];
image_header_t *header;
while (1) {
static struct option long_options[] = {
{"encrypt", no_argument, 0, 'e'},
{"decrypt", no_argument, 0, 'd'},
{"input", required_argument, 0, 'i'},
{"output", required_argument, 0, 'o'},
{0, 0, 0, 0 }
};
int option_index = 0;
int c = getopt_long(argc, argv, "dei:o:",
long_options, &option_index);
if (c == -1)
break;
switch (c) {
case 'd':
decrypt_opt++;
if (decrypt_opt > 1) {
fprintf(stderr, "%s: decrypt may only be specified once\n",
argv[0]);
show_usage(argv[0]);
}
break;
case 'e':
encrypt_opt++;
if (encrypt_opt > 1) {
fprintf(stderr, "%s: encrypt may only be specified once\n",
argv[0]);
show_usage(argv[0]);
}
break;
case 'i':
input_opt++;
if (input_opt > 1) {
fprintf(stderr, "%s: only one input file may be specified\n",
argv[0]);
show_usage(argv[0]);
}
if (strcmp("-", optarg) != 0) {
input_filename = optarg;
}
break;
case 'o':
output_opt++;
if (output_opt > 1) {
fprintf(stderr, "%s: only one output file may be specified\n",
argv[0]);
show_usage(argv[0]);
}
if (strcmp("-", optarg) != 0) {
output_filename = optarg;
}
break;
case '?':
exit(-1);
default:
abort();
}
}
if (decrypt_opt && encrypt_opt) {
fprintf(stderr, "%s: decrypt and encrypt may not be used together\n",
argv[0]);
show_usage(argv[0]);
}
if (!decrypt_opt && !encrypt_opt) {
fprintf(stderr, "%s: neither decrypt or encrypt were specified\n",
argv[0]);
show_usage(argv[0]);
}
temp_fd = fileno(tmpfile());
if (temp_fd < 0) {
fprintf(stderr, "Can't create temporary file\n");
exit(EXIT_FAILURE);
}
atexit(exit_cleanup);
DES_set_key_unchecked((const_DES_cblock *)DES_KEY, &schedule);
if (input_filename) {
input_fd = open(input_filename, O_RDONLY);
if (input_fd < 0) {
fprintf(stderr, "Can't open %s for reading: %s\n", input_filename,
strerror(errno));
exit(EXIT_FAILURE);
}
copy_file(input_fd, temp_fd);
close(input_fd);
}
else {
copy_file(STDIN_FILENO, temp_fd);
}
file_len = lseek(temp_fd, 0, SEEK_CUR);
if (file_len < 64) {
fprintf(stderr, "Not enough data\n");
exit(EXIT_FAILURE);
}
p = mmap(0, file_len, PROT_READ|PROT_WRITE, MAP_SHARED, temp_fd, 0);
if (p == MAP_FAILED) {
fprintf(stderr, "mmap failed: %s\n", strerror(errno));
exit(EXIT_FAILURE);
}
if (encrypt_opt) {
header = (image_header_t *)p;
off_t len = min(file_len,
ntohl(header->ih_size) + sizeof(image_header_t));
if (ntohl(header->ih_magic) != IH_MAGIC) {
fprintf(stderr, "Header magic incorrect: "
"expected 0x%08X, got 0x%08X\n",
IH_MAGIC, ntohl(header->ih_magic));
munmap(p, file_len);
exit(EXIT_FAILURE);
}
do_encrypt(p, len);
munmap(p, file_len);
if (len != file_len) {
if (ftruncate(temp_fd, len) < 0) {
fprintf(stderr, "ftruncate failed: %s\n", strerror(errno));
exit(EXIT_FAILURE);
}
}
}
if (decrypt_opt) {
off_t header_len = min(file_len, sizeof(image_header_t) + 3);
memcpy(buf, p, header_len);
do_decrypt(buf, header_len);
header = (image_header_t *)buf;
if (ntohl(header->ih_magic) != IH_MAGIC) {
fprintf(stderr, "Header magic incorrect: "
"expected 0x%08X, got 0x%08X\n",
IH_MAGIC, ntohl(header->ih_magic));
exit(EXIT_FAILURE);
}
do_decrypt(p, file_len);
munmap(p, file_len);
}
lseek(temp_fd, 0, SEEK_SET);
if (output_filename) {
output_fd = creat(output_filename, S_IRUSR|S_IWUSR|S_IRGRP|S_IROTH);
if (output_fd < 0) {
fprintf(stderr, "Can't open %s for writing: %s\n",
output_filename, strerror(errno));
exit(EXIT_FAILURE);
}
copy_file(temp_fd, output_fd);
close(output_fd);
}
else {
copy_file(temp_fd, STDOUT_FILENO);
}
exit(EXIT_SUCCESS);
return 0;
}
static void show_usage(const char *arg0)
{
fprintf(stderr, "usage: %s -d|-e [-i FILE] [-o FILE]\n\n", arg0);
fprintf(stderr, "%-15s %s\n", "-d, --decrypt", "decrypt data");
fprintf(stderr, "%-15s %s\n", "-e, --encrypt", "encrypt data");
fprintf(stderr, "%-15s %s\n", "-i, --input", "intput file (defaults to stdin)");
fprintf(stderr, "%-15s %s\n", "-o, --output", "output file (defaults to stdout)");
exit(-1);
}
static void exit_cleanup(void)
{
if (temp_fd >= 0) {
close(temp_fd);
}
}
static void copy_file(int src, int dst)
{
char buf[4096];
ssize_t size;
while ((size = read(src, buf, 4096)) > 0) {
write(dst, buf, size);
}
}
static void do_encrypt(void *p, off_t len)
{
DES_cblock *pblock;
int num_blocks;
num_blocks = len / 8;
pblock = (DES_cblock *) p;
while (num_blocks--) {
DES_ecb_encrypt(pblock, pblock, &schedule, DES_ENCRYPT);
pblock++;
}
num_blocks = (len - 3) / 8;
pblock = (DES_cblock *) (p + 3);
while (num_blocks--) {
DES_ecb_encrypt(pblock, pblock, &schedule, DES_ENCRYPT);
pblock++;
}
}
static void do_decrypt(void *p, off_t len)
{
DES_cblock *pblock;
int num_blocks;
num_blocks = (len - 3) / 8;
pblock = (DES_cblock *) (p + 3);
while (num_blocks--) {
DES_ecb_encrypt(pblock, pblock, &schedule, DES_DECRYPT);
pblock++;
}
num_blocks = len / 8;
pblock = (DES_cblock *) p;
while (num_blocks--) {
DES_ecb_encrypt(pblock, pblock, &schedule, DES_DECRYPT);
pblock++;
}
}