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[scarthgap,1/7] gnutls: Fix CVE-2026-33846

Message ID 20260520081403.3052797-1-hsimeliere.opensource@witekio.com
State New
Headers show
Series [scarthgap,1/7] gnutls: Fix CVE-2026-33846 | expand

Commit Message

Hugo Simeliere May 20, 2026, 8:13 a.m. UTC 
From: "Hugo SIMELIERE (Schneider Electric)" <hsimeliere.opensource@witekio.com>

Pick patch from [1] as mentioned in Debian report in [2].
Pick pre-patch [3] to minimize conflicts.

[1] https://gitlab.com/gnutls/gnutls/-/commit/65ab33fa54e34fba69d793735b7df3d383d1ff78
[2] https://security-tracker.debian.org/tracker/CVE-2026-33846
[3] https://gitlab.com/gnutls/gnutls/-/commit/9deffca528c23bbb218f5ec3bd4bb1bf4cbd1fc0

Signed-off-by: Hugo SIMELIERE (Schneider Electric) <hsimeliere.opensource@witekio.com>
Reviewed-by: Bruno VERNAY <bruno.vernay@se.com>
---
 .../gnutls/gnutls/CVE-2026-33846-pre.patch    | 97 +++++++++++++++++++
 .../gnutls/gnutls/CVE-2026-33846.patch        | 67 +++++++++++++
 meta/recipes-support/gnutls/gnutls_3.8.4.bb   |  2 +
 3 files changed, 166 insertions(+)
 create mode 100644 meta/recipes-support/gnutls/gnutls/CVE-2026-33846-pre.patch
 create mode 100644 meta/recipes-support/gnutls/gnutls/CVE-2026-33846.patch
diff mbox series

Patch

diff --git a/meta/recipes-support/gnutls/gnutls/CVE-2026-33846-pre.patch b/meta/recipes-support/gnutls/gnutls/CVE-2026-33846-pre.patch
new file mode 100644
index 0000000000..71266cb338
--- /dev/null
+++ b/meta/recipes-support/gnutls/gnutls/CVE-2026-33846-pre.patch
@@ -0,0 +1,97 @@ 
+From e51ef765b942968949e29797a73727c371397eea Mon Sep 17 00:00:00 2001
+From: Alexander Sosedkin <asosedkin@redhat.com>
+Date: Fri, 17 Apr 2026 17:49:31 +0200
+Subject: [PATCH 1/2] buffers: shorten merge_handshake_packet using recv_buf
+
+I had vague concerns about thread-safety of this,
+but then this pattern already exists within the file.
+
+CVE: CVE-2026-33846
+Upstream-Status: Backport [https://gitlab.com/gnutls/gnutls/-/commit/9deffca528c23bbb218f5ec3bd4bb1bf4cbd1fc0]
+
+Signed-off-by: Alexander Sosedkin <asosedkin@redhat.com>
+(cherry picked from commit 9deffca528c23bbb218f5ec3bd4bb1bf4cbd1fc0)
+Signed-off-by: Hugo SIMELIERE (Schneider Electric) <hsimeliere.opensource@witekio.com>
+---
+ lib/buffers.c | 52 +++++++++++++++++----------------------------------
+ 1 file changed, 17 insertions(+), 35 deletions(-)
+
+diff --git a/lib/buffers.c b/lib/buffers.c
+index 672380b05..d54c77022 100644
+--- a/lib/buffers.c
++++ b/lib/buffers.c
+@@ -967,9 +967,11 @@ static int merge_handshake_packet(gnutls_session_t session,
+ 	int exists = 0, i, pos = 0;
+ 	int ret;
+ 
++	handshake_buffer_st *recv_buf =
++		session->internals.handshake_recv_buffer;
++
+ 	for (i = 0; i < session->internals.handshake_recv_buffer_size; i++) {
+-		if (session->internals.handshake_recv_buffer[i].htype ==
+-		    hsk->htype) {
++		if (recv_buf[i].htype == hsk->htype) {
+ 			exists = 1;
+ 			pos = i;
+ 			break;
+@@ -1005,44 +1007,24 @@ static int merge_handshake_packet(gnutls_session_t session,
+ 		_gnutls_write_uint24(0, &hsk->header[6]);
+ 		_gnutls_write_uint24(hsk->length, &hsk->header[9]);
+ 
+-		_gnutls_handshake_buffer_move(
+-			&session->internals.handshake_recv_buffer[pos], hsk);
++		_gnutls_handshake_buffer_move(&recv_buf[pos], hsk);
+ 
+ 	} else {
+-		if (hsk->start_offset <
+-			    session->internals.handshake_recv_buffer[pos]
+-				    .start_offset &&
+-		    hsk->end_offset + 1 >=
+-			    session->internals.handshake_recv_buffer[pos]
+-				    .start_offset) {
+-			memcpy(&session->internals.handshake_recv_buffer[pos]
+-					.data.data[hsk->start_offset],
++		if (hsk->start_offset < recv_buf[pos].start_offset &&
++		    hsk->end_offset + 1 >= recv_buf[pos].start_offset) {
++			memcpy(&recv_buf[pos].data.data[hsk->start_offset],
+ 			       hsk->data.data, hsk->data.length);
+-			session->internals.handshake_recv_buffer[pos]
+-				.start_offset = hsk->start_offset;
+-			session->internals.handshake_recv_buffer[pos]
+-				.end_offset = MIN(
+-				hsk->end_offset,
+-				session->internals.handshake_recv_buffer[pos]
+-					.end_offset);
+-		} else if (hsk->end_offset >
+-				   session->internals.handshake_recv_buffer[pos]
+-					   .end_offset &&
+-			   hsk->start_offset <=
+-				   session->internals.handshake_recv_buffer[pos]
+-						   .end_offset +
+-					   1) {
+-			memcpy(&session->internals.handshake_recv_buffer[pos]
+-					.data.data[hsk->start_offset],
++			recv_buf[pos].start_offset = hsk->start_offset;
++			recv_buf[pos].end_offset =
++				MIN(hsk->end_offset, recv_buf[pos].end_offset);
++		} else if (hsk->end_offset > recv_buf[pos].end_offset &&
++			   hsk->start_offset <= recv_buf[pos].end_offset + 1) {
++			memcpy(&recv_buf[pos].data.data[hsk->start_offset],
+ 			       hsk->data.data, hsk->data.length);
+ 
+-			session->internals.handshake_recv_buffer[pos]
+-				.end_offset = hsk->end_offset;
+-			session->internals.handshake_recv_buffer[pos]
+-				.start_offset = MIN(
+-				hsk->start_offset,
+-				session->internals.handshake_recv_buffer[pos]
+-					.start_offset);
++			recv_buf[pos].end_offset = hsk->end_offset;
++			recv_buf[pos].start_offset = MIN(
++				hsk->start_offset, recv_buf[pos].start_offset);
+ 		}
+ 		_gnutls_handshake_buffer_clear(hsk);
+ 	}
+-- 
+2.43.0
+
diff --git a/meta/recipes-support/gnutls/gnutls/CVE-2026-33846.patch b/meta/recipes-support/gnutls/gnutls/CVE-2026-33846.patch
new file mode 100644
index 0000000000..e7d5cc6c2b
--- /dev/null
+++ b/meta/recipes-support/gnutls/gnutls/CVE-2026-33846.patch
@@ -0,0 +1,67 @@ 
+From 68e0c900c1111206fa4a135cdb43827f3b908284 Mon Sep 17 00:00:00 2001
+From: Alexander Sosedkin <asosedkin@redhat.com>
+Date: Fri, 17 Apr 2026 18:21:36 +0200
+Subject: [PATCH 2/2] buffers: add more checks to DTLS reassembly
+
+Previously, gnutls didn't check that DTLS fragments claimed
+a consistent message_length value.
+Additionally, a crucial array size check was missing,
+enabling an attacker to cause a heap overwrite.
+The updated version rejects fragments with mismatching length
+and adds a missing boundary check.
+
+Reported-by: Haruto Kimura (Stella)
+Reported-by: Oscar Reparaz
+Reported-by: Zou Dikai
+Fixes: #1816
+Fixes: #1838
+Fixes: #1839
+Fixes: CVE-2026-33846
+Fixes: GNUTLS-SA-2026-04-29-1
+CVSS: 7.4 High CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:N/I:H/A:H
+CVSS: 7.5 High CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H
+
+CVE: CVE-2026-33846
+Upstream-Status: Backport [https://gitlab.com/gnutls/gnutls/-/commit/65ab33fa54e34fba69d793735b7df3d383d1ff78]
+
+Signed-off-by: Alexander Sosedkin <asosedkin@redhat.com>
+(cherry picked from commit 65ab33fa54e34fba69d793735b7df3d383d1ff78)
+Signed-off-by: Hugo SIMELIERE (Schneider Electric) <hsimeliere.opensource@witekio.com>
+---
+ lib/buffers.c | 20 ++++++++++++++++++++
+ 1 file changed, 20 insertions(+)
+
+diff --git a/lib/buffers.c b/lib/buffers.c
+index d54c77022..5d4d16276 100644
+--- a/lib/buffers.c
++++ b/lib/buffers.c
+@@ -1010,6 +1010,26 @@ static int merge_handshake_packet(gnutls_session_t session,
+ 		_gnutls_handshake_buffer_move(&recv_buf[pos], hsk);
+ 
+ 	} else {
++		if (hsk->length != recv_buf[pos].length) {
++			/* inconsistent across fragments */
++			_gnutls_handshake_buffer_clear(hsk);
++			return gnutls_assert_val(
++				GNUTLS_E_UNEXPECTED_PACKET_LENGTH);
++		}
++		/* start_offset + data.length <= hsk->length <= max_length */
++		if (hsk->length < hsk->start_offset + hsk->data.length) {
++			/* impossible claims, overflow requested */
++			_gnutls_handshake_buffer_clear(hsk);
++			return gnutls_assert_val(
++				GNUTLS_E_UNEXPECTED_PACKET_LENGTH);
++		}
++		if (hsk->length > recv_buf[pos].data.max_length) {
++			/* we don't have this much allocated, overflow guard */
++			_gnutls_handshake_buffer_clear(hsk);
++			return gnutls_assert_val(
++				GNUTLS_E_UNEXPECTED_PACKET_LENGTH);
++		}
++
+ 		if (hsk->start_offset < recv_buf[pos].start_offset &&
+ 		    hsk->end_offset + 1 >= recv_buf[pos].start_offset) {
+ 			memcpy(&recv_buf[pos].data.data[hsk->start_offset],
+-- 
+2.43.0
+
diff --git a/meta/recipes-support/gnutls/gnutls_3.8.4.bb b/meta/recipes-support/gnutls/gnutls_3.8.4.bb
index ccb6a2b4b2..e40a654a8e 100644
--- a/meta/recipes-support/gnutls/gnutls_3.8.4.bb
+++ b/meta/recipes-support/gnutls/gnutls_3.8.4.bb
@@ -43,6 +43,8 @@  SRC_URI = "https://www.gnupg.org/ftp/gcrypt/gnutls/v${SHRT_VER}/gnutls-${PV}.tar
            file://CVE-2025-14831-7.patch \
            file://CVE-2025-14831-8.patch \
            file://CVE-2025-14831-9.patch \
+           file://CVE-2026-33846-pre.patch \
+           file://CVE-2026-33846.patch \
            "
 
 SRC_URI[sha256sum] = "2bea4e154794f3f00180fa2a5c51fe8b005ac7a31cd58bd44cdfa7f36ebc3a9b"