firmware-utils/buffalo-enc: add support for decrypting data with an offset

Signed-off-by: Felix Fietkau <nbd@openwrt.org>
SVN-Revision: 47185

diff --git a/tools/firmware-utils/src/buffalo-enc.c b/tools/firmware-utils/src/buffalo-enc.c
index 59b66ab930cc22ac42ccbe8709e46b850d760c10..794659eb41f5ffd666b1c44c17fcad76a4eaa432 100644 (file)
--- a/tools/firmware-utils/src/buffalo-enc.c
+++ b/tools/firmware-utils/src/buffalo-enc.c
@@ -34,6 +34,7 @@ static unsigned char seed = 'O';
 static char *product;
 static char *version;
 static int do_decrypt;
+static int offset;
 
 void usage(int status)
 {
@@ -52,6 +53,7 @@ void usage(int status)
 "  -p <product>    set product name to <product>\n"
 "  -v <version>    set version to <version>\n"
 "  -h              show this screen\n"
+"  -O              Offset of encrypted data in file (decryption)\n"
        );
 
        exit(status);
@@ -87,7 +89,7 @@ static int decrypt_file(void)
        ep.key = (unsigned char *) crypt_key;
        ep.longstate = longstate;
 
-       err = decrypt_buf(&ep, buf, src_len);
+       err = decrypt_buf(&ep, buf + offset, src_len - offset);
        if (err) {
                ERR("unable to decrypt '%s'", ifname);
                goto out;
@@ -100,7 +102,7 @@ static int decrypt_file(void)
        printf("Data len\t: %u\n", ep.datalen);
        printf("Checksum\t: 0x%08x\n", ep.csum);
 
-       err = write_buf_to_file(ofname, buf, ep.datalen);
+       err = write_buf_to_file(ofname, buf + offset, ep.datalen);
        if (err) {
                ERR("unable to write to file '%s'", ofname);
                goto out;
@@ -239,7 +241,7 @@ int main(int argc, char *argv[])
        while ( 1 ) {
                int c;
 
-               c = getopt(argc, argv, "adi:m:o:hlp:v:k:r:s:");
+               c = getopt(argc, argv, "adi:m:o:hlp:v:k:O:r:s:");
                if (c == -1)
                        break;
 
@@ -271,6 +273,9 @@ int main(int argc, char *argv[])
                case 's':
                        seed = strtoul(optarg, NULL, 16);
                        break;
+               case 'O':
+                       offset = strtoul(optarg, NULL, 0);
+                       break;
                case 'h':
                        usage(EXIT_SUCCESS);
                        break;