From 6c31ba10e97b6953c4f325f526f3e846dfea647a Mon Sep 17 00:00:00 2001 From: "dtucker@openbsd.org" Date: Fri, 1 Jul 2022 03:39:44 +0000 Subject: [PATCH] upstream: 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@ This is a roll-forward of the previous rollback now that the required changes in compat.c have been done. OpenBSD-Commit-ID: c7cd93730b3b9f53cdad3ae32462922834ef73eb --- sshconnect2.c | 16 ++++++++++------ sshd.c | 17 +++++++++++------ 2 files changed, 21 insertions(+), 12 deletions(-) diff --git a/sshconnect2.c b/sshconnect2.c index 5f87221b5..7fd5c2189 100644 --- a/sshconnect2.c +++ b/sshconnect2.c @@ -1,4 +1,4 @@ -/* $OpenBSD: sshconnect2.c,v 1.358 2022/06/24 10:45:06 dtucker Exp $ */ +/* $OpenBSD: sshconnect2.c,v 1.359 2022/07/01 03:39:44 dtucker Exp $ */ /* * Copyright (c) 2000 Markus Friedl. All rights reserved. * Copyright (c) 2008 Damien Miller. All rights reserved. @@ -218,6 +218,7 @@ ssh_kex2(struct ssh *ssh, char *host, struct sockaddr *hostaddr, u_short port, { char *myproposal[PROPOSAL_MAX] = { KEX_CLIENT }; char *s, *all_key; + char *prop_kex = NULL, *prop_enc = NULL, *prop_hostkey = NULL; int r, use_known_hosts_order = 0; xxx_host = host; @@ -243,10 +244,9 @@ ssh_kex2(struct ssh *ssh, char *host, struct sockaddr *hostaddr, u_short port, if ((s = kex_names_cat(options.kex_algorithms, "ext-info-c")) == NULL) fatal_f("kex_names_cat"); - myproposal[PROPOSAL_KEX_ALGS] = compat_kex_proposal(ssh, s); + myproposal[PROPOSAL_KEX_ALGS] = prop_kex = compat_kex_proposal(ssh, s); myproposal[PROPOSAL_ENC_ALGS_CTOS] = - compat_cipher_proposal(ssh, options.ciphers); - myproposal[PROPOSAL_ENC_ALGS_STOC] = + myproposal[PROPOSAL_ENC_ALGS_STOC] = prop_enc = compat_cipher_proposal(ssh, options.ciphers); myproposal[PROPOSAL_COMP_ALGS_CTOS] = myproposal[PROPOSAL_COMP_ALGS_STOC] = @@ -255,12 +255,12 @@ 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 */ - myproposal[PROPOSAL_SERVER_HOST_KEY_ALGS] = + myproposal[PROPOSAL_SERVER_HOST_KEY_ALGS] = prop_hostkey = compat_pkalg_proposal(ssh, order_hostkeyalgs(host, hostaddr, port, cinfo)); } else { /* Use specified HostkeyAlgorithms exactly */ - myproposal[PROPOSAL_SERVER_HOST_KEY_ALGS] = + myproposal[PROPOSAL_SERVER_HOST_KEY_ALGS] = prop_hostkey = compat_pkalg_proposal(ssh, options.hostkeyalgorithms); } @@ -303,6 +303,10 @@ ssh_kex2(struct ssh *ssh, char *host, struct sockaddr *hostaddr, u_short port, (r = ssh_packet_write_wait(ssh)) != 0) fatal_fr(r, "send packet"); #endif + /* Free only parts of proposal that were dynamically allocated here. */ + free(prop_kex); + free(prop_enc); + free(prop_hostkey); } /* diff --git a/sshd.c b/sshd.c index d80b5e0ba..e0680d3f5 100644 --- a/sshd.c +++ b/sshd.c @@ -1,4 +1,4 @@ -/* $OpenBSD: sshd.c,v 1.588 2022/06/24 10:45:06 dtucker Exp $ */ +/* $OpenBSD: sshd.c,v 1.589 2022/07/01 03:39:44 dtucker Exp $ */ /* * Author: Tatu Ylonen * Copyright (c) 1995 Tatu Ylonen , Espoo, Finland @@ -2368,12 +2368,14 @@ do_ssh2_kex(struct ssh *ssh) { char *myproposal[PROPOSAL_MAX] = { KEX_SERVER }; struct kex *kex; + char *prop_kex = NULL, *prop_enc = NULL, *prop_hostkey = NULL; int r; - myproposal[PROPOSAL_KEX_ALGS] = compat_kex_proposal(ssh, + myproposal[PROPOSAL_KEX_ALGS] = prop_kex = compat_kex_proposal(ssh, options.kex_algorithms); - myproposal[PROPOSAL_ENC_ALGS_CTOS] = compat_cipher_proposal(ssh, - options.ciphers); + myproposal[PROPOSAL_ENC_ALGS_CTOS] = + myproposal[PROPOSAL_ENC_ALGS_STOC] = prop_enc = + compat_cipher_proposal(ssh, options.ciphers); myproposal[PROPOSAL_ENC_ALGS_STOC] = compat_cipher_proposal(ssh, options.ciphers); myproposal[PROPOSAL_MAC_ALGS_CTOS] = @@ -2388,8 +2390,8 @@ do_ssh2_kex(struct ssh *ssh) ssh_packet_set_rekey_limits(ssh, options.rekey_limit, options.rekey_interval); - myproposal[PROPOSAL_SERVER_HOST_KEY_ALGS] = compat_pkalg_proposal( - ssh, list_hostkey_types()); + myproposal[PROPOSAL_SERVER_HOST_KEY_ALGS] = prop_hostkey = + compat_pkalg_proposal(ssh, list_hostkey_types()); /* start key exchange */ if ((r = kex_setup(ssh, myproposal)) != 0) @@ -2424,6 +2426,9 @@ do_ssh2_kex(struct ssh *ssh) (r = ssh_packet_write_wait(ssh)) != 0) fatal_fr(r, "send test"); #endif + free(prop_kex); + free(prop_enc); + free(prop_hostkey); debug("KEX done"); }