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| author | Ed Maste <emaste@FreeBSD.org> | 2023-02-06 16:26:08 +0000 |
|---|---|---|
| committer | Ed Maste <emaste@FreeBSD.org> | 2023-02-08 21:04:36 +0000 |
| commit | 296ec8eae0c834088a491643a937d881bfb4b5dd (patch) | |
| tree | 14a2f3838287e2b5595093bc7bcf94e7910510d7 | |
| parent | 04c6f6ce1b4d912d925aba0d0f5f0f1d03d9084a (diff) | |
| download | src-296ec8eae0c834088a491643a937d881bfb4b5dd.tar.gz src-296ec8eae0c834088a491643a937d881bfb4b5dd.zip | |
ssh: fix double-free caused by compat_kex_proposal()
Security: CVE-2023-25136
Obtained from: OpenSSH-portable commit 12da78233364
Sponsored by: The FreeBSD Foundation
(cherry picked from commit fe1371e8f3d7336748d291a7360b2aacce943fb1)
| -rw-r--r-- | crypto/openssh/compat.c | 16 |
1 files changed, 8 insertions, 8 deletions
diff --git a/crypto/openssh/compat.c b/crypto/openssh/compat.c index 46dfe3a9c2e7..478a9403eeaa 100644 --- a/crypto/openssh/compat.c +++ b/crypto/openssh/compat.c @@ -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; } |