diff options
| author | djm@openbsd.org <djm@openbsd.org> | 2023-02-02 12:10:05 +0000 |
|---|---|---|
| committer | Damien Miller <djm@mindrot.org> | 2023-02-02 23:14:09 +1100 |
| commit | 12da7823336434a403f25c7cc0c2c6aed0737a35 (patch) | |
| tree | 2f2691666cace2a1fcabf1a11ffb18fd57eddd1f | |
| parent | 79efd95ab5ff99f4cb3a955e2d713b3f54fb807e (diff) | |
upstream: fix double-free caused by compat_kex_proposal(); bz3522
by dtucker@, ok me
OpenBSD-Commit-ID: 2bfc37cd2d41f67dad64c17a64cf2cd3806a5c80
| -rw-r--r-- | compat.c | 16 |
1 files changed, 8 insertions, 8 deletions
@@ -1,4 +1,4 @@ -/* $OpenBSD: compat.c,v 1.120 2022/07/01 03:35:45 dtucker Exp $ */ +/* $OpenBSD: compat.c,v 1.121 2023/02/02 12:10:05 djm Exp $ */ /* * Copyright (c) 1999, 2000, 2001, 2002 Markus Friedl. All rights reserved. * @@ -190,26 +190,26 @@ compat_pkalg_proposal(struct ssh *ssh, char *pkalg_prop) char * compat_kex_proposal(struct ssh *ssh, char *p) { - char *cp = NULL; + char *cp = NULL, *cp2 = NULL; if ((ssh->compat & (SSH_BUG_CURVE25519PAD|SSH_OLD_DHGEX)) == 0) return xstrdup(p); debug2_f("original KEX proposal: %s", p); if ((ssh->compat & SSH_BUG_CURVE25519PAD) != 0) - if ((p = match_filter_denylist(p, + if ((cp = match_filter_denylist(p, "curve25519-sha256@libssh.org")) == NULL) fatal("match_filter_denylist failed"); if ((ssh->compat & SSH_OLD_DHGEX) != 0) { - cp = p; - if ((p = match_filter_denylist(p, + if ((cp2 = match_filter_denylist(cp ? cp : p, "diffie-hellman-group-exchange-sha256," "diffie-hellman-group-exchange-sha1")) == NULL) fatal("match_filter_denylist failed"); free(cp); + cp = cp2; } - debug2_f("compat KEX proposal: %s", p); - if (*p == '\0') + if (cp == NULL || *cp == '\0') fatal("No supported key exchange algorithms found"); - return p; + debug2_f("compat KEX proposal: %s", cp); + return cp; } |