static void
msn_dc_send_handshake(MsnDirectConn *dc)
{
MsnDirectConnPacket *p;
gchar *h;
p = msn_dc_new_packet(DC_NONCE_PACKET_SIZE);
h = (gchar *)p->data;
msn_push32le(h, 0); /* NUL */
msn_push32le(h, dc->slpcall->slplink->slp_seq_id++);
/* More NUL stuff */
msn_push64le(h, 0);
msn_push64le(h, 0);
msn_push32le(h, 0);
/* Flags */
msn_push32le(h, P2P_DC_HANDSHAKE);
/* The real Nonce, yay! */
memcpy(h, dc->nonce, 16);
msn_dc_enqueue_packet(dc, p);
}
static char *
msn_rps_encrypt(MsnNexus *nexus)
{
char usr_key_base[MSN_USER_KEY_SIZE], *usr_key;
const char magic1[] = "SESSION KEY HASH";
const char magic2[] = "SESSION KEY ENCRYPTION";
PurpleCipherContext *hmac;
size_t len;
guchar *hash;
char *key1, *key2, *key3;
gsize key1_len;
const char *iv;
char *nonce_fixed;
char *cipher;
char *response;
usr_key = &usr_key_base[0];
/* Header */
msn_push32le(usr_key, 28); /* Header size */
msn_push32le(usr_key, CRYPT_MODE_CBC); /* Crypt mode */
msn_push32le(usr_key, CIPHER_TRIPLE_DES); /* Cipher type */
msn_push32le(usr_key, HASH_SHA1); /* Hash type */
msn_push32le(usr_key, 8); /* IV size */
msn_push32le(usr_key, 20); /* Hash size */
msn_push32le(usr_key, 72); /* Cipher size */
/* Data */
iv = usr_key;
msn_push32le(usr_key, rand());
msn_push32le(usr_key, rand());
hash = (guchar *)usr_key;
usr_key += 20; /* Remaining is cipher data */
key1 = (char *)purple_base64_decode((const char *)nexus->tokens[MSN_AUTH_MESSENGER].secret, &key1_len);
key2 = rps_create_key(key1, key1_len, magic1, sizeof(magic1) - 1);
key3 = rps_create_key(key1, key1_len, magic2, sizeof(magic2) - 1);
len = strlen(nexus->nonce);
hmac = purple_cipher_context_new_by_name("hmac", NULL);
purple_cipher_context_set_option(hmac, "hash", "sha1");
purple_cipher_context_set_key_with_len(hmac, (guchar *)key2, 24);
purple_cipher_context_append(hmac, (guchar *)nexus->nonce, len);
purple_cipher_context_digest(hmac, 20, hash, NULL);
purple_cipher_context_destroy(hmac);
/* We need to pad this to 72 bytes, apparently */
nonce_fixed = g_malloc(len + 8);
memcpy(nonce_fixed, nexus->nonce, len);
memset(nonce_fixed + len, 0x08, 8);
cipher = des3_cbc(key3, iv, nonce_fixed, len + 8, FALSE);
g_free(nonce_fixed);
memcpy(usr_key, cipher, 72);
g_free(key1);
g_free(key2);
g_free(key3);
g_free(cipher);
response = purple_base64_encode((guchar *)usr_key_base, MSN_USER_KEY_SIZE);
return response;
}
