Don't leak the strings allocated by order_hostkeyalgs() and

list_hostkey_types() that are passed to compat_pkalg_proposal().
Part of github PR#324 from ZoltanFridrich, ok djm@

diff --git a/usr.bin/ssh/sshconnect2.c b/usr.bin/ssh/sshconnect2.c
index 1171e5a..2cd3ef0 100644 (file)
--- a/usr.bin/ssh/sshconnect2.c
+++ b/usr.bin/ssh/sshconnect2.c
@@ -1,4 +1,4 @@
-/* $OpenBSD: sshconnect2.c,v 1.356 2022/02/01 23:32:51 djm Exp $ */
+/* $OpenBSD: sshconnect2.c,v 1.357 2022/06/24 04:37:00 dtucker Exp $ */
 /*
  * Copyright (c) 2000 Markus Friedl.  All rights reserved.
  * Copyright (c) 2008 Damien Miller.  All rights reserved.
@@ -109,6 +109,7 @@ first_alg(const char *algs)
        return ret;
 }
 
+/* Returns an allocated string that the caller must free. */
 static char *
 order_hostkeyalgs(char *host, struct sockaddr *hostaddr, u_short port,
     const struct ssh_conn_info *cinfo)
@@ -212,7 +213,7 @@ ssh_kex2(struct ssh *ssh, char *host, struct sockaddr *hostaddr, u_short port,
     const struct ssh_conn_info *cinfo)
 {
        char *myproposal[PROPOSAL_MAX] = { KEX_CLIENT };
-       char *s, *all_key;
+       char *s, *all_key, *hostkeyalgs = NULL;
        int r, use_known_hosts_order = 0;
 
        xxx_host = host;
@@ -250,9 +251,10 @@ ssh_kex2(struct ssh *ssh, char *host, struct sockaddr *hostaddr, u_short port,
            myproposal[PROPOSAL_MAC_ALGS_STOC] = options.macs;
        if (use_known_hosts_order) {
                /* Query known_hosts and prefer algorithms that appear there */
+               hostkeyalgs = order_hostkeyalgs(host, hostaddr, port, cinfo);
                myproposal[PROPOSAL_SERVER_HOST_KEY_ALGS] =
-                   compat_pkalg_proposal(ssh,
-                   order_hostkeyalgs(host, hostaddr, port, cinfo));
+                   compat_pkalg_proposal(ssh, hostkeyalgs);
+               free(hostkeyalgs);
        } else {
                /* Use specified HostkeyAlgorithms exactly */
                myproposal[PROPOSAL_SERVER_HOST_KEY_ALGS] =

diff --git a/usr.bin/ssh/sshd.c b/usr.bin/ssh/sshd.c
index d6fbbef..f91e04a 100644 (file)
--- a/usr.bin/ssh/sshd.c
+++ b/usr.bin/ssh/sshd.c
@@ -1,4 +1,4 @@
-/* $OpenBSD: sshd.c,v 1.586 2022/06/17 01:00:03 dtucker Exp $ */
+/* $OpenBSD: sshd.c,v 1.587 2022/06/24 04:37:00 dtucker Exp $ */
 /*
  * Author: Tatu Ylonen <ylo@cs.hut.fi>
  * Copyright (c) 1995 Tatu Ylonen <ylo@cs.hut.fi>, Espoo, Finland
@@ -560,6 +560,7 @@ append_hostkey_type(struct sshbuf *b, const char *s)
                fatal_fr(r, "sshbuf_putf");
 }
 
+/* Returns an allocated string that the caller must free. */
 static char *
 list_hostkey_types(void)
 {
@@ -2194,6 +2195,7 @@ static void
 do_ssh2_kex(struct ssh *ssh)
 {
        char *myproposal[PROPOSAL_MAX] = { KEX_SERVER };
+       char *hostkey_types = NULL;
        struct kex *kex;
        int r;
 
@@ -2215,8 +2217,10 @@ do_ssh2_kex(struct ssh *ssh)
                ssh_packet_set_rekey_limits(ssh, options.rekey_limit,
                    options.rekey_interval);
 
+       hostkey_types = list_hostkey_types();
        myproposal[PROPOSAL_SERVER_HOST_KEY_ALGS] = compat_pkalg_proposal(
-           ssh, list_hostkey_types());
+           ssh, hostkey_types);
+       free(hostkey_types);
 
        /* start key exchange */
        if ((r = kex_setup(ssh, myproposal)) != 0)