diff options
Diffstat (limited to 'libotr/libotr-4.1.1/toolkit/otr_readforge.c')
| -rw-r--r-- | libotr/libotr-4.1.1/toolkit/otr_readforge.c | 133 |
1 files changed, 133 insertions, 0 deletions
diff --git a/libotr/libotr-4.1.1/toolkit/otr_readforge.c b/libotr/libotr-4.1.1/toolkit/otr_readforge.c new file mode 100644 index 0000000..733f221 --- /dev/null +++ b/libotr/libotr-4.1.1/toolkit/otr_readforge.c @@ -0,0 +1,133 @@ +/* + * Off-the-Record Messaging Toolkit + * Copyright (C) 2004-2012 Ian Goldberg, Chris Alexander, Nikita Borisov + * <otr@cypherpunks.ca> + * + * This program is free software; you can redistribute it and/or modify + * it under the terms of version 2 of the GNU General Public License 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., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA + */ + +/* system headers */ +#include <stdio.h> +#include <stdlib.h> + +/* libotr headers */ +#include "proto.h" + +/* toolkit headers */ +#include "readotr.h" +#include "parse.h" +#include "sesskeys.h" +#include "sha1hmac.h" +#include "ctrmode.h" + +static void usage(const char *progname) +{ + fprintf(stderr, "Usage: %s aeskey [new_message]\n" +"Read an OTR Data Message from stdin. Use the given AES key to\n" +"verify its MAC and decrypt the message to stdout. If new_message\n" +"is given, output a new OTR Data Message with the same fields as the\n" +"original, but with the message replaced by new_message\n", progname); + exit(1); +} + +int main(int argc, char **argv) +{ + unsigned char *aeskey; + unsigned char mackey[20]; + unsigned char macval[20]; + size_t aeskeylen; + unsigned char *plaintext, *ciphertext; + char *otrmsg = NULL; + DataMsg datamsg; + + if (argc != 2 && argc != 3) { + usage(argv[0]); + } + + argv_to_buf(&aeskey, &aeskeylen, argv[1]); + if (!aeskey) { + usage(argv[0]); + } + + if (aeskeylen != 16) { + fprintf(stderr, "The AES key must be 32 hex chars long.\n"); + usage(argv[0]); + } + + otrmsg = readotr(stdin); + if (otrmsg == NULL) { + fprintf(stderr, "No OTR Data Message found on stdin.\n"); + exit(1); + } + + if (otrl_proto_message_type(otrmsg) != OTRL_MSGTYPE_DATA) { + fprintf(stderr, "OTR Non-Data Message found on stdin.\n"); + exit(1); + } + + datamsg = parse_datamsg(otrmsg); + free(otrmsg); + if (datamsg == NULL) { + fprintf(stderr, "Invalid OTR Data Message found on stdin.\n"); + exit(1); + } + + /* Create the MAC key */ + sesskeys_make_mac(mackey, aeskey); + + /* Check the MAC */ + sha1hmac(macval, mackey, datamsg->macstart, + datamsg->macend - datamsg->macstart); + if (memcmp(macval, datamsg->mac, 20)) { + fprintf(stderr, "MAC does not verify: wrong AES key?\n"); + } else { + /* Decrypt the message */ + plaintext = malloc(datamsg->encmsglen+1); + if (!plaintext) { + fprintf(stderr, "Out of memory!\n"); + exit(1); + } + aes_ctr_crypt(plaintext, datamsg->encmsg, datamsg->encmsglen, + aeskey, datamsg->ctr); + plaintext[datamsg->encmsglen] = '\0'; + printf("Plaintext: ``%s''\n", plaintext); + free(plaintext); + } + + /* Do we want to forge a message? */ + if (argv[2] != NULL) { + char *newdatamsg; + size_t newlen = strlen(argv[2]); + ciphertext = malloc(newlen); + if (!ciphertext && newlen > 0) { + fprintf(stderr, "Out of memory!\n"); + exit(1); + } + aes_ctr_crypt(ciphertext, (const unsigned char *)argv[2], newlen, + aeskey, datamsg->ctr); + free(datamsg->encmsg); + datamsg->encmsg = ciphertext; + datamsg->encmsglen = newlen; + + newdatamsg = remac_datamsg(datamsg, mackey); + + printf("%s\n", newdatamsg); + free(newdatamsg); + } + + free_datamsg(datamsg); + free(aeskey); + fflush(stdout); + return 0; +} |