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Fix CVE-2026-3497

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Fix information disclosure or denial of service due
to uninitialized variables in gssapi-keyex

Resolves: RHEL-155825

Signed-off-by: Zoltan Fridrich <zfridric@redhat.com>
This commit is contained in:
Zoltan Fridrich 2026-03-16 16:28:51 +01:00
parent 08d29bf220
commit 59346084f6
2 changed files with 27 additions and 20 deletions
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40
openssh-9.6p1-gssapi-keyex.patch
View File

@ -1240,7 +1240,7 @@ diff --color -ruNp a/kexgen.c b/kexgen.c
const struct sshbuf *client_version,
diff --color -ruNp a/kexgssc.c b/kexgssc.c
--- a/kexgssc.c 1970-01-01 01:00:00.000000000 +0100
+++ b/kexgssc.c 2024-10-14 15:18:02.491798105 +0200
+++ b/kexgssc.c 2026-03-13 12:25:23.115812190 +0100
@@ -0,0 +1,706 @@
+/*
+ * Copyright (c) 2001-2009 Simon Wilkinson. All rights reserved.
@ -1369,7 +1369,7 @@ diff --color -ruNp a/kexgssc.c b/kexgssc.c
+
+ /* Verify that the hash matches the MIC we just got. */
+ if (GSS_ERROR(ssh_gssapi_checkmic(gss, &gss->buf, &gss->msg_tok)))
+ sshpkt_disconnect(ssh, "Hash's MIC didn't verify");
+ ssh_packet_disconnect(ssh, "Hash's MIC didn't verify");
+
+ gss_release_buffer(&gss->minor, &gss->msg_tok);
+
@ -1592,10 +1592,10 @@ diff --color -ruNp a/kexgssc.c b/kexgssc.c
+ fatal("Failed to read token: %s", ssh_err(r));
+ /* If we're already complete - protocol error */
+ if (gss->major == GSS_S_COMPLETE)
+ sshpkt_disconnect(ssh, "Protocol error: received token when complete");
+ ssh_packet_disconnect(ssh, "Protocol error: received token when complete");
+ } else {
+ if (gss->major != GSS_S_COMPLETE)
+ sshpkt_disconnect(ssh, "Protocol error: did not receive final token");
+ ssh_packet_disconnect(ssh, "Protocol error: did not receive final token");
+ }
+ if ((r = sshpkt_get_end(ssh)) != 0)
+ fatal("Expecting end of packet.");
@ -1731,7 +1731,7 @@ diff --color -ruNp a/kexgssc.c b/kexgssc.c
+
+ /* Verify that the hash matches the MIC we just got. */
+ if (GSS_ERROR(ssh_gssapi_checkmic(gss, &gss->buf, &gss->msg_tok)))
+ sshpkt_disconnect(ssh, "Hash's MIC didn't verify");
+ ssh_packet_disconnect(ssh, "Hash's MIC didn't verify");
+
+ gss_release_buffer(&gss->minor, &gss->msg_tok);
+
@ -1932,10 +1932,10 @@ diff --color -ruNp a/kexgssc.c b/kexgssc.c
+ fatal("Failed to read token: %s", ssh_err(r));
+ /* If we're already complete - protocol error */
+ if (gss->major == GSS_S_COMPLETE)
+ sshpkt_disconnect(ssh, "Protocol error: received token when complete");
+ ssh_packet_disconnect(ssh, "Protocol error: received token when complete");
+ } else {
+ if (gss->major != GSS_S_COMPLETE)
+ sshpkt_disconnect(ssh, "Protocol error: did not receive final token");
+ ssh_packet_disconnect(ssh, "Protocol error: did not receive final token");
+ }
+ if ((r = sshpkt_get_end(ssh)) != 0)
+ fatal("Expecting end of packet.");
@ -1950,8 +1950,8 @@ diff --color -ruNp a/kexgssc.c b/kexgssc.c
+#endif /* defined(GSSAPI) && defined(WITH_OPENSSL) */
diff --color -ruNp a/kexgsss.c b/kexgsss.c
--- a/kexgsss.c 1970-01-01 01:00:00.000000000 +0100
+++ b/kexgsss.c 2024-10-14 15:18:02.491798105 +0200
@@ -0,0 +1,601 @@
+++ b/kexgsss.c 2026-03-13 12:32:17.556172591 +0100
@@ -0,0 +1,603 @@
+/*
+ * Copyright (c) 2001-2009 Simon Wilkinson. All rights reserved.
+ *
@ -2083,7 +2083,7 @@ diff --color -ruNp a/kexgsss.c b/kexgsss.c
+{
+ struct kex *kex = ssh->kex;
+ Gssctxt *gss = kex->gss;
+ gss_buffer_desc msg_tok;
+ gss_buffer_desc msg_tok = GSS_C_EMPTY_BUFFER;
+ u_char hash[SSH_DIGEST_MAX_LENGTH];
+ size_t hashlen;
+ struct sshbuf *shared_secret = NULL;
@ -2167,7 +2167,8 @@ diff --color -ruNp a/kexgsss.c b/kexgsss.c
+ Gssctxt *gss = kex->gss;
+ struct sshbuf *empty;
+ struct sshbuf *client_pubkey = NULL;
+ gss_buffer_desc recv_tok, send_tok = GSS_C_EMPTY_BUFFER;
+ gss_buffer_desc recv_tok = GSS_C_EMPTY_BUFFER;
+ gss_buffer_desc send_tok = GSS_C_EMPTY_BUFFER;
+ OM_uint32 ret_flags = 0;
+ int r;
+
@ -2243,7 +2244,8 @@ diff --color -ruNp a/kexgsss.c b/kexgsss.c
+ struct ssh *ssh)
+{
+ Gssctxt *gss = ssh->kex->gss;
+ gss_buffer_desc recv_tok, send_tok = GSS_C_EMPTY_BUFFER;
+ gss_buffer_desc recv_tok = GSS_C_EMPTY_BUFFER;
+ gss_buffer_desc send_tok = GSS_C_EMPTY_BUFFER;
+ OM_uint32 ret_flags = 0;
+ int r;
+
@ -2334,7 +2336,7 @@ diff --color -ruNp a/kexgsss.c b/kexgsss.c
+{
+ struct kex *kex = ssh->kex;
+ Gssctxt *gss = kex->gss;
+ gss_buffer_desc msg_tok;
+ gss_buffer_desc msg_tok = GSS_C_EMPTY_BUFFER;
+ u_char hash[SSH_DIGEST_MAX_LENGTH];
+ size_t hashlen;
+ const BIGNUM *pub_key, *dh_p, *dh_g;
@ -2475,10 +2477,8 @@ diff --color -ruNp a/kexgsss.c b/kexgsss.c
+ fatal("GSS_GEX, bad parameters: %d !< %d !< %d", min, nbits, max);
+
+ kex->dh = mm_choose_dh(min, nbits, max);
+ if (kex->dh == NULL) {
+ sshpkt_disconnect(ssh, "Protocol error: no matching group found");
+ fatal("Protocol error: no matching group found");
+ }
+ if (kex->dh == NULL)
+ ssh_packet_disconnect(ssh, "Protocol error: no matching group found");
+
+ DH_get0_pqg(kex->dh, &dh_p, NULL, &dh_g);
+ if ((r = sshpkt_start(ssh, SSH2_MSG_KEXGSS_GROUP)) != 0 ||
@ -2510,7 +2510,8 @@ diff --color -ruNp a/kexgsss.c b/kexgsss.c
+ struct ssh *ssh)
+{
+ Gssctxt *gss = ssh->kex->gss;
+ gss_buffer_desc recv_tok, send_tok = GSS_C_EMPTY_BUFFER;
+ gss_buffer_desc recv_tok = GSS_C_EMPTY_BUFFER;
+ gss_buffer_desc send_tok = GSS_C_EMPTY_BUFFER;
+ OM_uint32 ret_flags = 0;
+ int r;
+
@ -2537,7 +2538,8 @@ diff --color -ruNp a/kexgsss.c b/kexgsss.c
+ struct ssh *ssh)
+{
+ Gssctxt *gss = ssh->kex->gss;
+ gss_buffer_desc recv_tok, send_tok = GSS_C_EMPTY_BUFFER;
+ gss_buffer_desc recv_tok = GSS_C_EMPTY_BUFFER;
+ gss_buffer_desc send_tok = GSS_C_EMPTY_BUFFER;
+ OM_uint32 ret_flags = 0;
+ int r;
+

7
openssh.spec
View File

@ -47,7 +47,7 @@
# Do not forget to bump pam_ssh_agent_auth release if you rewind the main package release to 1
%global openssh_ver 9.9p1
%global openssh_rel 4
%global openssh_rel 5
%global pam_ssh_agent_ver 0.10.4
%global pam_ssh_agent_rel 7
@ -748,6 +748,11 @@ test -f %{sysconfig_anaconda} && \
%endif
%changelog
* Mon Mar 16 2026 Zoltan Fridrich <zfridric@redhat.com> - 9.9p1-5
- CVE-2026-3497: Fix information disclosure or denial of service due
to uninitialized variables in gssapi-keyex
Resolves: RHEL-155825
* Wed Feb 25 2026 Dmitry Belyavskiy <dbelyavs@redhat.com> - 9.9p1-4
- Provide a way to skip unsupported ML-KEM hybrid algorithms in FIPS mode
Resolves: RHEL-151580