upstream commit

adapt kex to sshbuf and struct ssh; ok djm@

1 files changed, 120 insertions, 74 deletions

diff --git a/kexdhc.c b/kexdhc.c
index cd12df33d..52b752295 100644
--- a/kexdhc.c
+++ b/kexdhc.c
@@ -1,4 +1,4 @@
-/* $OpenBSD: kexdhc.c,v 1.16 2015/01/19 19:52:16 markus Exp $ */
+/* $OpenBSD: kexdhc.c,v 1.17 2015/01/19 20:16:15 markus Exp $ */
 /*
  * Copyright (c) 2001 Markus Friedl.  All rights reserved.
  *
@@ -36,129 +36,175 @@
 #include <string.h>
 #include <signal.h>
 
-#include "xmalloc.h"
-#include "buffer.h"
-#include "key.h"
+#include "sshkey.h"
 #include "cipher.h"
+#include "digest.h"
 #include "kex.h"
 #include "log.h"
 #include "packet.h"
 #include "dh.h"
 #include "ssh2.h"
+#include "dispatch.h"
+#include "compat.h"
+#include "ssherr.h"
+#include "sshbuf.h"
 
-void
-kexdh_client(Kex *kex)
+static int input_kex_dh(int, u_int32_t, void *);
+
+int
+kexdh_client(struct ssh *ssh)
 {
-        BIGNUM *dh_server_pub = NULL, *shared_secret = NULL;
-        DH *dh;
-        Key *server_host_key;
-        u_char *server_host_key_blob = NULL, *signature = NULL;
-        u_char *kbuf, *hash;
-        u_int klen, slen, sbloblen, hashlen;
-        int kout;
+        struct kex *kex = ssh->kex;
+        int r;
 
         /* generate and send 'e', client DH public key */
         switch (kex->kex_type) {
         case KEX_DH_GRP1_SHA1:
-                dh = dh_new_group1();
+                kex->dh = dh_new_group1();
                 break;
         case KEX_DH_GRP14_SHA1:
-                dh = dh_new_group14();
+                kex->dh = dh_new_group14();
                 break;
         default:
-                fatal("%s: Unexpected KEX type %d", __func__, kex->kex_type);
+                r = SSH_ERR_INVALID_ARGUMENT;
+                goto out;
+        }
+        if (kex->dh == NULL) {
+                r = SSH_ERR_ALLOC_FAIL;
+                goto out;
         }
-        dh_gen_key(dh, kex->we_need * 8);
-        packet_start(SSH2_MSG_KEXDH_INIT);
-        packet_put_bignum2(dh->pub_key);
-        packet_send();
-
         debug("sending SSH2_MSG_KEXDH_INIT");
+        if ((r = dh_gen_key(kex->dh, kex->we_need * 8)) != 0 ||
+            (r = sshpkt_start(ssh, SSH2_MSG_KEXDH_INIT)) != 0 ||
+            (r = sshpkt_put_bignum2(ssh, kex->dh->pub_key)) != 0 ||
+            (r = sshpkt_send(ssh)) != 0)
+                goto out;
 #ifdef DEBUG_KEXDH
-        DHparams_print_fp(stderr, dh);
+        DHparams_print_fp(stderr, kex->dh);
         fprintf(stderr, "pub= ");
-        BN_print_fp(stderr, dh->pub_key);
+        BN_print_fp(stderr, kex->dh->pub_key);
         fprintf(stderr, "\n");
 #endif
-
         debug("expecting SSH2_MSG_KEXDH_REPLY");
-        packet_read_expect(SSH2_MSG_KEXDH_REPLY);
+        ssh_dispatch_set(ssh, SSH2_MSG_KEXDH_REPLY, &input_kex_dh);
+        r = 0;
+ out:
+        return r;
+}
 
+static int
+input_kex_dh(int type, u_int32_t seq, void *ctxt)
+{
+        struct ssh *ssh = ctxt;
+        struct kex *kex = ssh->kex;
+        BIGNUM *dh_server_pub = NULL, *shared_secret = NULL;
+        struct sshkey *server_host_key = NULL;
+        u_char *kbuf = NULL, *server_host_key_blob = NULL, *signature = NULL;
+        u_char hash[SSH_DIGEST_MAX_LENGTH];
+        size_t klen = 0, slen, sbloblen, hashlen;
+        int kout, r;
+
+        if (kex->verify_host_key == NULL) {
+                r = SSH_ERR_INVALID_ARGUMENT;
+                goto out;
+        }
         /* key, cert */
-        server_host_key_blob = packet_get_string(&sbloblen);
-        server_host_key = key_from_blob(server_host_key_blob, sbloblen);
-        if (server_host_key == NULL)
-                fatal("cannot decode server_host_key_blob");
-        if (server_host_key->type != kex->hostkey_type)
-                fatal("type mismatch for decoded server_host_key_blob");
-        if (kex->verify_host_key == NULL)
-                fatal("cannot verify server_host_key");
-        if (kex->verify_host_key(server_host_key) == -1)
-                fatal("server_host_key verification failed");
-
+        if ((r = sshpkt_get_string(ssh, &server_host_key_blob,
+            &sbloblen)) != 0 ||
+            (r = sshkey_from_blob(server_host_key_blob, sbloblen,
+            &server_host_key)) != 0)
+                goto out;
+        if (server_host_key->type != kex->hostkey_type) {
+                r = SSH_ERR_KEY_TYPE_MISMATCH;
+                goto out;
+        }
+        if (kex->verify_host_key(server_host_key, ssh) == -1) {
+                r = SSH_ERR_SIGNATURE_INVALID;
+                goto out;
+        }
         /* DH parameter f, server public DH key */
-        if ((dh_server_pub = BN_new()) == NULL)
-                fatal("dh_server_pub == NULL");
-        packet_get_bignum2(dh_server_pub);
-
+        if ((dh_server_pub = BN_new()) == NULL) {
+                r = SSH_ERR_ALLOC_FAIL;
+                goto out;
+        }
+        /* signed H */
+        if ((r = sshpkt_get_bignum2(ssh, dh_server_pub)) != 0 ||
+            (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;
+        }
 
-        /* signed H */
-        signature = packet_get_string(&slen);
-        packet_check_eom();
-
-        if (!dh_pub_is_valid(dh, dh_server_pub))
-                packet_disconnect("bad server public DH value");
-
-        klen = DH_size(dh);
-        kbuf = xmalloc(klen);
-        if ((kout = DH_compute_key(kbuf, dh_server_pub, dh)) < 0)
-                fatal("DH_compute_key: failed");
+        klen = DH_size(kex->dh);
+        if ((kbuf = malloc(klen)) == NULL ||
+            (shared_secret = BN_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;
+                goto out;
+        }
 #ifdef DEBUG_KEXDH
         dump_digest("shared secret", kbuf, kout);
 #endif
-        if ((shared_secret = BN_new()) == NULL)
-                fatal("kexdh_client: BN_new failed");
-        if (BN_bin2bn(kbuf, kout, shared_secret) == NULL)
-                fatal("kexdh_client: BN_bin2bn failed");
-        explicit_bzero(kbuf, klen);
-        free(kbuf);
 
         /* calc and verify H */
-        kex_dh_hash(
+        hashlen = sizeof(hash);
+        if ((r = kex_dh_hash(
             kex->client_version_string,
             kex->server_version_string,
-            buffer_ptr(kex->my), buffer_len(kex->my),
-            buffer_ptr(kex->peer), buffer_len(kex->peer),
+            sshbuf_ptr(kex->my), sshbuf_len(kex->my),
+            sshbuf_ptr(kex->peer), sshbuf_len(kex->peer),
             server_host_key_blob, sbloblen,
-            dh->pub_key,
+            kex->dh->pub_key,
             dh_server_pub,
             shared_secret,
-            &hash, &hashlen
-        );
-        free(server_host_key_blob);
-        BN_clear_free(dh_server_pub);
-        DH_free(dh);
+            hash, &hashlen)) != 0)
+                goto out;
 
-        if (key_verify(server_host_key, signature, slen, hash, hashlen) != 1)
-                fatal("key_verify failed for server_host_key");
-        key_free(server_host_key);
-        free(signature);
+        if ((r = sshkey_verify(server_host_key, signature, slen, hash, hashlen,
+            ssh->compat)) != 0)
+                goto out;
 
         /* save session id */
         if (kex->session_id == NULL) {
                 kex->session_id_len = hashlen;
-                kex->session_id = xmalloc(kex->session_id_len);
+                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);
         }
 
-        kex_derive_keys_bn(kex, hash, hashlen, shared_secret);
-        BN_clear_free(shared_secret);
-        kex_finish(kex);
+        if ((r = kex_derive_keys_bn(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_server_pub)
+                BN_clear_free(dh_server_pub);
+        if (kbuf) {
+                explicit_bzero(kbuf, klen);
+                free(kbuf);
+        }
+        if (shared_secret)
+                BN_clear_free(shared_secret);
+        sshkey_free(server_host_key);
+        free(server_host_key_blob);
+        free(signature);
+        return r;
 }
 #endif /* WITH_OPENSSL */