- set_busy_status(ssh->frontend, BUSY_WAITING); /* wait for server */
- crWaitUntil(pktin);
- if (pktin->type != s->kex_reply_value) {
- bombout(("expected key exchange reply packet from server"));
- crStop(0);
- }
- set_busy_status(ssh->frontend, BUSY_CPU); /* cogitate */
- ssh_pkt_getstring(pktin, &s->hostkeydata, &s->hostkeylen);
- s->f = ssh2_pkt_getmp(pktin);
- if (!s->f) {
- bombout(("unable to parse key exchange reply packet"));
- crStop(0);
- }
- ssh_pkt_getstring(pktin, &s->sigdata, &s->siglen);
+ {
+ char *keydata;
+ ssh_pkt_getstring(pktin, &keydata, &s->rsakeylen);
+ s->rsakeydata = snewn(s->rsakeylen, char);
+ memcpy(s->rsakeydata, keydata, s->rsakeylen);
+ }
+
+ s->rsakey = ssh_rsakex_newkey(s->rsakeydata, s->rsakeylen);
+ if (!s->rsakey) {
+ sfree(s->rsakeydata);
+ bombout(("unable to parse RSA public key from server"));
+ crStop(0);
+ }
+
+ hash_string(ssh->kex->hash, ssh->exhash, s->rsakeydata, s->rsakeylen);
+
+ /*
+ * Next, set up a shared secret K, of precisely KLEN -
+ * 2*HLEN - 49 bits, where KLEN is the bit length of the
+ * RSA key modulus and HLEN is the bit length of the hash
+ * we're using.
+ */
+ {
+ int klen = ssh_rsakex_klen(s->rsakey);
+ int nbits = klen - (2*ssh->kex->hash->hlen*8 + 49);
+ int i, byte = 0;
+ unsigned char *kstr1, *kstr2, *outstr;
+ int kstr1len, kstr2len, outstrlen;
+
+ s->K = bn_power_2(nbits - 1);
+
+ for (i = 0; i < nbits; i++) {
+ if ((i & 7) == 0) {
+ byte = random_byte();
+ }
+ bignum_set_bit(s->K, i, (byte >> (i & 7)) & 1);
+ }
+
+ /*
+ * Encode this as an mpint.
+ */
+ kstr1 = ssh2_mpint_fmt(s->K, &kstr1len);
+ kstr2 = snewn(kstr2len = 4 + kstr1len, unsigned char);
+ PUT_32BIT(kstr2, kstr1len);
+ memcpy(kstr2 + 4, kstr1, kstr1len);
+
+ /*
+ * Encrypt it with the given RSA key.
+ */
+ outstrlen = (klen + 7) / 8;
+ outstr = snewn(outstrlen, unsigned char);
+ ssh_rsakex_encrypt(ssh->kex->hash, kstr2, kstr2len,
+ outstr, outstrlen, s->rsakey);
+
+ /*
+ * And send it off in a return packet.
+ */
+ s->pktout = ssh2_pkt_init(SSH2_MSG_KEXRSA_SECRET);
+ ssh2_pkt_addstring_start(s->pktout);
+ ssh2_pkt_addstring_data(s->pktout, outstr, outstrlen);
+ ssh2_pkt_send_noqueue(ssh, s->pktout);
+
+ hash_string(ssh->kex->hash, ssh->exhash, outstr, outstrlen);
+
+ sfree(kstr2);
+ sfree(kstr1);
+ sfree(outstr);
+ }
+
+ ssh_rsakex_freekey(s->rsakey);