libssh: Fix CVE-2026-3731

Pick commits according to [1]

[1] https://security-tracker.debian.org/tracker/CVE-2026-3731
[2] https://www.libssh.org/security/advisories/libssh-2026-sftp-extensions.txt

Signed-off-by: Vijay Anusuri <vanusuri@mvista.com>
Signed-off-by: Anuj Mittal <anuj.mittal@oss.qualcomm.com>

3 files changed, 148 insertions, 0 deletions

diff --git a/meta-oe/recipes-support/libssh/libssh/CVE-2026-3731-1.patch b/meta-oe/recipes-support/libssh/libssh/CVE-2026-3731-1.patch
new file mode 100644
index 0000000000..69a012d294
--- /dev/null
+++ b/meta-oe/recipes-support/libssh/libssh/CVE-2026-3731-1.patch
@@ -0,0 +1,44 @@
+From f80670a7aba86cbb442c9b115c9eaf4ca04601b8 Mon Sep 17 00:00:00 2001
+From: Jakub Jelen <jjelen@redhat.com>
+Date: Thu, 11 Dec 2025 13:22:44 +0100
+Subject: [PATCH] sftp: Fix out-of-bound read from sftp extensions
+MIME-Version: 1.0
+Content-Type: text/plain; charset=UTF-8
+Content-Transfer-Encoding: 8bit
+
+Signed-off-by: Jakub Jelen <jjelen@redhat.com>
+Reviewed-by: Pavol Žáčik <pzacik@redhat.com>
+(cherry picked from commit 855a0853ad3abd4a6cd85ce06fce6d8d4c7a0b60)
+
+Upstream-Status: Backport [https://git.libssh.org/projects/libssh.git/commit/?id=f80670a7aba86cbb442c9b115c9eaf4ca04601b8]
+CVE: CVE-2026-3731
+Signed-off-by: Vijay Anusuri <vanusuri@mvista.com>
+---
+ src/sftp.c | 4 ++--
+ 1 file changed, 2 insertions(+), 2 deletions(-)
+
+diff --git a/src/sftp.c b/src/sftp.c
+index e01012a8..4a77141b 100644
+--- a/src/sftp.c
++++ b/src/sftp.c
+@@ -768,7 +768,7 @@ const char *sftp_extensions_get_name(sftp_session sftp, unsigned int idx) {
+     return NULL;
+   }
+ 
+-  if (idx > sftp->ext->count) {
++  if (idx >= sftp->ext->count) {
+     ssh_set_error_invalid(sftp->session);
+     return NULL;
+   }
+@@ -784,7 +784,7 @@ const char *sftp_extensions_get_data(sftp_session sftp, unsigned int idx) {
+     return NULL;
+   }
+ 
+-  if (idx > sftp->ext->count) {
++  if (idx >= sftp->ext->count) {
+     ssh_set_error_invalid(sftp->session);
+     return NULL;
+   }
+-- 
+2.43.0
+
diff --git a/meta-oe/recipes-support/libssh/libssh/CVE-2026-3731-2.patch b/meta-oe/recipes-support/libssh/libssh/CVE-2026-3731-2.patch
new file mode 100644
index 0000000000..ae0ffefa03
--- /dev/null
+++ b/meta-oe/recipes-support/libssh/libssh/CVE-2026-3731-2.patch
@@ -0,0 +1,102 @@
+From 02c6f5f7ec8629a7cff6a28cde9701ab10304540 Mon Sep 17 00:00:00 2001
+From: Jakub Jelen <jjelen@redhat.com>
+Date: Thu, 11 Dec 2025 13:21:23 +0100
+Subject: Reproducer for out of bounds read of SFTP extensions
+MIME-Version: 1.0
+Content-Type: text/plain; charset=UTF-8
+Content-Transfer-Encoding: 8bit
+
+Signed-off-by: Jakub Jelen <jjelen@redhat.com>
+Reviewed-by: Pavol Žáčik <pzacik@redhat.com>
+(cherry picked from commit b90b7f24517efa7ab21506db9379aa3dce9fee7d)
+
+Upstream-Status: Backport [https://git.libssh.org/projects/libssh.git/commit/?id=02c6f5f7ec8629a7cff6a28cde9701ab10304540]
+CVE: CVE-2026-3731
+Signed-off-by: Vijay Anusuri <vanusuri@mvista.com>
+---
+ tests/client/torture_sftp_init.c | 62 +++++++++++++++++++++++++++++++++++++++-
+ 1 file changed, 61 insertions(+), 1 deletion(-)
+
+diff --git a/tests/client/torture_sftp_init.c b/tests/client/torture_sftp_init.c
+index a17f01fe2..cdc244263 100644
+--- a/tests/client/torture_sftp_init.c
++++ b/tests/client/torture_sftp_init.c
+@@ -72,6 +72,63 @@ static void session_setup_channel(void **state)
+     assert_non_null(s->ssh.tsftp);
+ }
+ 
++static void session_setup_extensions(void **state)
++{
++    struct torture_state *s = *state;
++    struct passwd *pwd = NULL;
++    int rc, count;
++    const char *name = NULL, *data = NULL;
++    sftp_session sftp = NULL;
++
++    pwd = getpwnam("bob");
++    assert_non_null(pwd);
++
++    rc = setuid(pwd->pw_uid);
++    assert_return_code(rc, errno);
++
++    s->ssh.session = torture_ssh_session(s,
++                                         TORTURE_SSH_SERVER,
++                                         NULL,
++                                         TORTURE_SSH_USER_ALICE,
++                                         NULL);
++    assert_non_null(s->ssh.session);
++
++    s->ssh.tsftp = torture_sftp_session(s->ssh.session);
++    assert_non_null(s->ssh.tsftp);
++    sftp = s->ssh.tsftp->sftp;
++
++    /* null parameter */
++    count = sftp_extensions_get_count(NULL);
++    assert_int_equal(count, 0);
++
++    count = sftp_extensions_get_count(sftp);
++    assert_int_not_equal(count, 0);
++
++    /* first null parameter */
++    name = sftp_extensions_get_name(NULL, 0);
++    assert_null(name);
++    data = sftp_extensions_get_data(NULL, 0);
++    assert_null(data);
++
++    /* First extension */
++    name = sftp_extensions_get_name(sftp, 0);
++    assert_non_null(name);
++    data = sftp_extensions_get_data(sftp, 0);
++    assert_non_null(data);
++
++    /* Last extension */
++    name = sftp_extensions_get_name(sftp, count - 1);
++    assert_non_null(name);
++    data = sftp_extensions_get_data(sftp, count - 1);
++    assert_non_null(data);
++
++    /* Overrun */
++    name = sftp_extensions_get_name(sftp, count);
++    assert_null(name);
++    data = sftp_extensions_get_data(sftp, count);
++    assert_null(data);
++}
++
+ static int session_teardown(void **state)
+ {
+     struct torture_state *s = *state;
+@@ -92,7 +149,10 @@ int torture_run_tests(void) {
+                                         session_teardown),
+         cmocka_unit_test_setup_teardown(session_setup_channel,
+                                         NULL,
+-                                        session_teardown)
++                                        session_teardown),
++        cmocka_unit_test_setup_teardown(session_setup_extensions,
++                                        NULL,
++                                        session_teardown),
+     };
+ 
+     ssh_init();
+-- 
+cgit v1.2.3
+
diff --git a/meta-oe/recipes-support/libssh/libssh_0.10.6.bb b/meta-oe/recipes-support/libssh/libssh_0.10.6.bb
index de37719b09..614b656216 100644
--- a/meta-oe/recipes-support/libssh/libssh_0.10.6.bb
+++ b/meta-oe/recipes-support/libssh/libssh_0.10.6.bb
@@ -22,6 +22,8 @@ SRC_URI = "git://git.libssh.org/projects/libssh.git;protocol=https;branch=stable
            file://CVE-2025-8277-2.patch \
            file://CVE-2025-8277-3.patch \
            file://CVE-2025-8277-4.patch \
+           file://CVE-2026-3731-1.patch \
+           file://CVE-2026-3731-2.patch \
           "
 SRCREV = "10e09e273f69e149389b3e0e5d44b8c221c2e7f6"