summaryrefslogtreecommitdiff
path: root/kexgexs.c
diff options
context:
space:
mode:
Diffstat (limited to 'kexgexs.c')
-rw-r--r--kexgexs.c197
1 files changed, 62 insertions, 135 deletions
diff --git a/kexgexs.c b/kexgexs.c
index 9c281d28..8ee3aacc 100644
--- a/kexgexs.c
+++ b/kexgexs.c
@@ -1,4 +1,4 @@
-/* $OpenBSD: kexgexs.c,v 1.24 2015/01/26 06:10:03 djm Exp $ */
+/* $OpenBSD: kexgexs.c,v 1.42 2019/01/23 00:30:41 djm Exp $ */
/*
* Copyright (c) 2000 Niels Provos. All rights reserved.
* Copyright (c) 2001 Markus Friedl. All rights reserved.
@@ -28,7 +28,6 @@
#ifdef WITH_OPENSSL
-#include <sys/param.h> /* MIN MAX */
#include <stdarg.h>
#include <stdio.h>
@@ -37,6 +36,8 @@
#include <openssl/dh.h>
+#include "openbsd-compat/openssl-compat.h"
+
#include "sshkey.h"
#include "cipher.h"
#include "digest.h"
@@ -53,15 +54,14 @@
#include "dispatch.h"
#include "ssherr.h"
#include "sshbuf.h"
+#include "misc.h"
-static int input_kex_dh_gex_request(int, u_int32_t, void *);
-static int input_kex_dh_gex_init(int, u_int32_t, void *);
+static int input_kex_dh_gex_request(int, u_int32_t, struct ssh *);
+static int input_kex_dh_gex_init(int, u_int32_t, struct ssh *);
int
kexgex_server(struct ssh *ssh)
{
- ssh_dispatch_set(ssh, SSH2_MSG_KEX_DH_GEX_REQUEST_OLD,
- &input_kex_dh_gex_request);
ssh_dispatch_set(ssh, SSH2_MSG_KEX_DH_GEX_REQUEST,
&input_kex_dh_gex_request);
debug("expecting SSH2_MSG_KEX_DH_GEX_REQUEST");
@@ -69,46 +69,29 @@ kexgex_server(struct ssh *ssh)
}
static int
-input_kex_dh_gex_request(int type, u_int32_t seq, void *ctxt)
+input_kex_dh_gex_request(int type, u_int32_t seq, struct ssh *ssh)
{
- struct ssh *ssh = ctxt;
struct kex *kex = ssh->kex;
int r;
u_int min = 0, max = 0, nbits = 0;
+ const BIGNUM *dh_p, *dh_g;
- switch (type) {
- case SSH2_MSG_KEX_DH_GEX_REQUEST:
- debug("SSH2_MSG_KEX_DH_GEX_REQUEST received");
- if ((r = sshpkt_get_u32(ssh, &min)) != 0 ||
- (r = sshpkt_get_u32(ssh, &nbits)) != 0 ||
- (r = sshpkt_get_u32(ssh, &max)) != 0 ||
- (r = sshpkt_get_end(ssh)) != 0)
- goto out;
- kex->nbits = nbits;
- kex->min = min;
- kex->max = max;
- min = MAX(DH_GRP_MIN, min);
- max = MIN(DH_GRP_MAX, max);
- nbits = MAX(DH_GRP_MIN, nbits);
- nbits = MIN(DH_GRP_MAX, nbits);
- break;
- case SSH2_MSG_KEX_DH_GEX_REQUEST_OLD:
- debug("SSH2_MSG_KEX_DH_GEX_REQUEST_OLD received");
- if ((r = sshpkt_get_u32(ssh, &nbits)) != 0 ||
- (r = sshpkt_get_end(ssh)) != 0)
- goto out;
- kex->nbits = nbits;
- /* unused for old GEX */
- kex->min = min = DH_GRP_MIN;
- kex->max = max = DH_GRP_MAX;
- break;
- default:
- r = SSH_ERR_INVALID_ARGUMENT;
+ debug("SSH2_MSG_KEX_DH_GEX_REQUEST received");
+ if ((r = sshpkt_get_u32(ssh, &min)) != 0 ||
+ (r = sshpkt_get_u32(ssh, &nbits)) != 0 ||
+ (r = sshpkt_get_u32(ssh, &max)) != 0 ||
+ (r = sshpkt_get_end(ssh)) != 0)
goto out;
- }
+ kex->nbits = nbits;
+ kex->min = min;
+ kex->max = max;
+ min = MAXIMUM(DH_GRP_MIN, min);
+ max = MINIMUM(DH_GRP_MAX, max);
+ nbits = MAXIMUM(DH_GRP_MIN, nbits);
+ nbits = MINIMUM(DH_GRP_MAX, nbits);
if (kex->max < kex->min || kex->nbits < kex->min ||
- kex->max < kex->nbits) {
+ kex->max < kex->nbits || kex->max < DH_GRP_MIN) {
r = SSH_ERR_DH_GEX_OUT_OF_RANGE;
goto out;
}
@@ -121,9 +104,10 @@ input_kex_dh_gex_request(int type, u_int32_t seq, void *ctxt)
goto out;
}
debug("SSH2_MSG_KEX_DH_GEX_GROUP sent");
+ DH_get0_pqg(kex->dh, &dh_p, NULL, &dh_g);
if ((r = sshpkt_start(ssh, SSH2_MSG_KEX_DH_GEX_GROUP)) != 0 ||
- (r = sshpkt_put_bignum2(ssh, kex->dh->p)) != 0 ||
- (r = sshpkt_put_bignum2(ssh, kex->dh->g)) != 0 ||
+ (r = sshpkt_put_bignum2(ssh, dh_p)) != 0 ||
+ (r = sshpkt_put_bignum2(ssh, dh_g)) != 0 ||
(r = sshpkt_send(ssh)) != 0)
goto out;
@@ -131,10 +115,6 @@ input_kex_dh_gex_request(int type, u_int32_t seq, void *ctxt)
if ((r = dh_gen_key(kex->dh, kex->we_need * 8)) != 0)
goto out;
- /* old KEX does not use min/max in kexgex_hash() */
- if (type == SSH2_MSG_KEX_DH_GEX_REQUEST_OLD)
- kex->min = kex->max = -1;
-
debug("expecting SSH2_MSG_KEX_DH_GEX_INIT");
ssh_dispatch_set(ssh, SSH2_MSG_KEX_DH_GEX_INIT, &input_kex_dh_gex_init);
r = 0;
@@ -143,134 +123,81 @@ input_kex_dh_gex_request(int type, u_int32_t seq, void *ctxt)
}
static int
-input_kex_dh_gex_init(int type, u_int32_t seq, void *ctxt)
+input_kex_dh_gex_init(int type, u_int32_t seq, struct ssh *ssh)
{
- struct ssh *ssh = ctxt;
struct kex *kex = ssh->kex;
- BIGNUM *shared_secret = NULL, *dh_client_pub = NULL;
+ BIGNUM *dh_client_pub = NULL;
+ const BIGNUM *pub_key, *dh_p, *dh_g;
+ struct sshbuf *shared_secret = NULL;
+ struct sshbuf *server_host_key_blob = NULL;
struct sshkey *server_host_public, *server_host_private;
- u_char *kbuf = NULL, *signature = NULL, *server_host_key_blob = NULL;
+ u_char *signature = NULL;
u_char hash[SSH_DIGEST_MAX_LENGTH];
- size_t sbloblen, slen;
- size_t klen = 0, hashlen;
- int kout, r;
+ size_t slen, hashlen;
+ int r;
- if (kex->load_host_public_key == NULL ||
- kex->load_host_private_key == NULL) {
- r = SSH_ERR_INVALID_ARGUMENT;
- goto out;
- }
- server_host_public = kex->load_host_public_key(kex->hostkey_type,
- kex->hostkey_nid, ssh);
- server_host_private = kex->load_host_private_key(kex->hostkey_type,
- kex->hostkey_nid, ssh);
- if (server_host_public == NULL) {
- r = SSH_ERR_NO_HOSTKEY_LOADED;
+ if ((r = kex_load_hostkey(ssh, &server_host_private,
+ &server_host_public)) != 0)
goto out;
- }
/* key, cert */
- if ((dh_client_pub = BN_new()) == NULL) {
- r = SSH_ERR_ALLOC_FAIL;
- goto out;
- }
- if ((r = sshpkt_get_bignum2(ssh, dh_client_pub)) != 0 ||
+ if ((r = sshpkt_get_bignum2(ssh, &dh_client_pub)) != 0 ||
(r = sshpkt_get_end(ssh)) != 0)
goto out;
-
-#ifdef DEBUG_KEXDH
- fprintf(stderr, "dh_client_pub= ");
- BN_print_fp(stderr, dh_client_pub);
- fprintf(stderr, "\n");
- debug("bits %d", BN_num_bits(dh_client_pub));
-#endif
-
-#ifdef DEBUG_KEXDH
- DHparams_print_fp(stderr, kex->dh);
- fprintf(stderr, "pub= ");
- BN_print_fp(stderr, kex->dh->pub_key);
- fprintf(stderr, "\n");
-#endif
- if (!dh_pub_is_valid(kex->dh, dh_client_pub)) {
- sshpkt_disconnect(ssh, "bad client public DH value");
- r = SSH_ERR_MESSAGE_INCOMPLETE;
+ if ((shared_secret = sshbuf_new()) == NULL) {
+ r = SSH_ERR_ALLOC_FAIL;
goto out;
}
-
- klen = DH_size(kex->dh);
- if ((kbuf = malloc(klen)) == NULL ||
- (shared_secret = BN_new()) == NULL) {
+ if ((r = kex_dh_compute_key(kex, dh_client_pub, shared_secret)) != 0)
+ goto out;
+ if ((server_host_key_blob = sshbuf_new()) == NULL) {
r = SSH_ERR_ALLOC_FAIL;
goto out;
}
- if ((kout = DH_compute_key(kbuf, dh_client_pub, kex->dh)) < 0 ||
- BN_bin2bn(kbuf, kout, shared_secret) == NULL) {
- r = SSH_ERR_LIBCRYPTO_ERROR;
- goto out;
- }
-#ifdef DEBUG_KEXDH
- dump_digest("shared secret", kbuf, kout);
-#endif
- if ((r = sshkey_to_blob(server_host_public, &server_host_key_blob,
- &sbloblen)) != 0)
+ if ((r = sshkey_putb(server_host_public, server_host_key_blob)) != 0)
goto out;
+
/* calc H */
+ DH_get0_key(kex->dh, &pub_key, NULL);
+ DH_get0_pqg(kex->dh, &dh_p, NULL, &dh_g);
hashlen = sizeof(hash);
if ((r = kexgex_hash(
kex->hash_alg,
- kex->client_version_string,
- kex->server_version_string,
- sshbuf_ptr(kex->peer), sshbuf_len(kex->peer),
- sshbuf_ptr(kex->my), sshbuf_len(kex->my),
- server_host_key_blob, sbloblen,
+ kex->client_version,
+ kex->server_version,
+ kex->peer,
+ kex->my,
+ server_host_key_blob,
kex->min, kex->nbits, kex->max,
- kex->dh->p, kex->dh->g,
+ dh_p, dh_g,
dh_client_pub,
- kex->dh->pub_key,
- shared_secret,
+ pub_key,
+ sshbuf_ptr(shared_secret), sshbuf_len(shared_secret),
hash, &hashlen)) != 0)
goto out;
- /* save session id := H */
- if (kex->session_id == NULL) {
- kex->session_id_len = hashlen;
- kex->session_id = malloc(kex->session_id_len);
- if (kex->session_id == NULL) {
- r = SSH_ERR_ALLOC_FAIL;
- goto out;
- }
- memcpy(kex->session_id, hash, kex->session_id_len);
- }
-
/* sign H */
- if ((r = kex->sign(server_host_private, server_host_public,
- &signature, &slen, hash, hashlen, ssh->compat)) < 0)
+ if ((r = kex->sign(ssh, server_host_private, server_host_public,
+ &signature, &slen, hash, hashlen, kex->hostkey_alg)) < 0)
goto out;
- /* destroy_sensitive_data(); */
-
- /* send server hostkey, DH pubkey 'f' and singed H */
+ /* send server hostkey, DH pubkey 'f' and signed H */
if ((r = sshpkt_start(ssh, SSH2_MSG_KEX_DH_GEX_REPLY)) != 0 ||
- (r = sshpkt_put_string(ssh, server_host_key_blob, sbloblen)) != 0 ||
- (r = sshpkt_put_bignum2(ssh, kex->dh->pub_key)) != 0 || /* f */
+ (r = sshpkt_put_stringb(ssh, server_host_key_blob)) != 0 ||
+ (r = sshpkt_put_bignum2(ssh, pub_key)) != 0 || /* f */
(r = sshpkt_put_string(ssh, signature, slen)) != 0 ||
(r = sshpkt_send(ssh)) != 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;
- if (dh_client_pub)
- BN_clear_free(dh_client_pub);
- if (kbuf) {
- explicit_bzero(kbuf, klen);
- free(kbuf);
- }
- if (shared_secret)
- BN_clear_free(shared_secret);
- free(server_host_key_blob);
+ BN_clear_free(dh_client_pub);
+ sshbuf_free(shared_secret);
+ sshbuf_free(server_host_key_blob);
free(signature);
return r;
}
generated by cgit v1.2.3 (git 2.25.1) at 2025-10-03 02:19:06 +0000