upstream: factor out kex_dh_compute_key() - it's shared between
plain DH KEX and DH GEX in both the client and server implementations
from markus@ ok djm@
OpenBSD-Commit-ID: 12186e18791fffcd4642c82e7e0cfdd7ea37e2ec
diff --git a/kexgexc.c b/kexgexc.c
index 0425309..600d91a 100644
--- a/kexgexc.c
+++ b/kexgexc.c
@@ -1,4 +1,4 @@
-/* $OpenBSD: kexgexc.c,v 1.31 2019/01/21 09:55:52 djm Exp $ */
+/* $OpenBSD: kexgexc.c,v 1.32 2019/01/21 10:03:37 djm Exp $ */
/*
* Copyright (c) 2000 Niels Provos. All rights reserved.
* Copyright (c) 2001 Markus Friedl. All rights reserved.
@@ -143,13 +143,14 @@
input_kex_dh_gex_reply(int type, u_int32_t seq, struct ssh *ssh)
{
struct kex *kex = ssh->kex;
- BIGNUM *dh_server_pub = NULL, *shared_secret = NULL;
+ BIGNUM *dh_server_pub = NULL;
const BIGNUM *pub_key, *dh_p, *dh_g;
+ struct sshbuf *shared_secret = NULL;
struct sshkey *server_host_key = NULL;
- u_char *kbuf = NULL, *signature = NULL, *server_host_key_blob = NULL;
+ u_char *signature = NULL, *server_host_key_blob = NULL;
u_char hash[SSH_DIGEST_MAX_LENGTH];
- size_t klen = 0, slen, sbloblen, hashlen;
- int kout, r;
+ size_t slen, sbloblen, hashlen;
+ int r;
debug("got SSH2_MSG_KEX_DH_GEX_REPLY");
if (kex->verify_host_key == NULL) {
@@ -177,32 +178,12 @@
(r = sshpkt_get_string(ssh, &signature, &slen)) != 0 ||
(r = sshpkt_get_end(ssh)) != 0)
goto out;
-#ifdef DEBUG_KEXDH
- fprintf(stderr, "dh_server_pub= ");
- BN_print_fp(stderr, dh_server_pub);
- fprintf(stderr, "\n");
- debug("bits %d", BN_num_bits(dh_server_pub));
-#endif
- if (!dh_pub_is_valid(kex->dh, dh_server_pub)) {
- sshpkt_disconnect(ssh, "bad server public DH value");
- r = SSH_ERR_MESSAGE_INCOMPLETE;
- goto out;
- }
-
- klen = DH_size(kex->dh);
- if ((kbuf = malloc(klen)) == NULL ||
- (shared_secret = BN_new()) == NULL) {
+ if ((shared_secret = sshbuf_new()) == NULL) {
r = SSH_ERR_ALLOC_FAIL;
goto out;
}
- if ((kout = DH_compute_key(kbuf, dh_server_pub, kex->dh)) < 0 ||
- BN_bin2bn(kbuf, kout, shared_secret) == NULL) {
- r = SSH_ERR_LIBCRYPTO_ERROR;
+ if ((r = kex_dh_compute_key(kex, dh_server_pub, shared_secret)) != 0)
goto out;
- }
-#ifdef DEBUG_KEXDH
- dump_digest("shared secret", kbuf, kout);
-#endif
if (ssh->compat & SSH_OLD_DHGEX)
kex->min = kex->max = -1;
@@ -221,7 +202,7 @@
dh_p, dh_g,
pub_key,
dh_server_pub,
- shared_secret,
+ sshbuf_ptr(shared_secret), sshbuf_len(shared_secret),
hash, &hashlen)) != 0)
goto out;
@@ -229,18 +210,14 @@
hashlen, kex->hostkey_alg, ssh->compat)) != 0)
goto out;
- if ((r = kex_derive_keys_bn(ssh, hash, hashlen, shared_secret)) == 0)
+ if ((r = kex_derive_keys(ssh, hash, hashlen, shared_secret)) == 0)
r = kex_send_newkeys(ssh);
out:
explicit_bzero(hash, sizeof(hash));
DH_free(kex->dh);
kex->dh = NULL;
BN_clear_free(dh_server_pub);
- if (kbuf) {
- explicit_bzero(kbuf, klen);
- free(kbuf);
- }
- BN_clear_free(shared_secret);
+ sshbuf_free(shared_secret);
sshkey_free(server_host_key);
free(server_host_key_blob);
free(signature);