libwebsockets: fix CVE-2025-11678

Backport a fix from Debian:
https://sources.debian.org/patches/libwebsockets/4.3.5-1+deb13u1/CVE-2025-11678.patch
Upstream commit:
https://github.com/warmcat/libwebsockets/commit/2bb9598562b37c942ba5b04bcde3f7fdf66a9d3a

Signed-off-by: Bruno VERNAY <bruno.vernay@se.com>
Signed-off-by: Hugo SIMELIERE <hsimeliere.opensource@witekio.com>
Signed-off-by: Anuj Mittal <anuj.mittal@oss.qualcomm.com>
(cherry picked from commit 5fab8bd31b32892acf3d8b56b240a7958890beac)
Signed-off-by: Gyorgy Sarvari <skandigraun@gmail.com>
Signed-off-by: Anuj Mittal <anuj.mittal@oss.qualcomm.com>

2 files changed, 129 insertions, 0 deletions

diff --git a/meta-oe/recipes-connectivity/libwebsockets/libwebsockets/CVE-2025-11678.patch b/meta-oe/recipes-connectivity/libwebsockets/libwebsockets/CVE-2025-11678.patch
new file mode 100644
index 0000000000..3489a7e6a1
--- /dev/null
+++ b/meta-oe/recipes-connectivity/libwebsockets/libwebsockets/CVE-2025-11678.patch
@@ -0,0 +1,128 @@
+From e1d4c32bf773b8cf01eb5e368a4a21679e0b670a Mon Sep 17 00:00:00 2001
+From: Hugo SIMELIERE <hsimeliere.opensource@witekio.com>
+Date: Tue, 18 Nov 2025 17:03:33 +0100
+Subject: [PATCH] NN-2025-0103: ADNS crafted response overflow
+
+This document contains sensitive information collected during our
+security research activities related with the Libwebsockets library made
+by Andy Green (warmcat).
+
++-------------------------------------------------------------------------------------------------------+
+| Report information                                                                                    |
++:===================================:+:===============================================================:+
+| Vendor                              | warmcat                                                         |
++-------------------------------------+-----------------------------------------------------------------+
+| Vendor URL                          | https://libwebsockets.org/git/libwebsockets                     |
++-------------------------------------+-----------------------------------------------------------------+
+| Affected component                  | Ecostruxure Automation Expert                                   |
++-------------------------------------+-----------------------------------------------------------------+
+| Affected version                    | 4.4                                                             |
++-------------------------------------+-----------------------------------------------------------------+
+| Vulnerability                       | CWE-121: Stack-based Buffer Overflow                            |
++-------------------------------------+-----------------------------------------------------------------+
+| Proposed CVSS v3.1 Base Score       | 7.5                                                             |
++-------------------------------------+-----------------------------------------------------------------+
+| Proposed CVSS v3.1 Vector           | CVSS:4.0/AV:A/AC:L/AT:P/PR:N/UI:P/VC:H/VI:H/VA:H/SC:N/SI:N/SA:N |
++-------------------------------------+-----------------------------------------------------------------+
+
++-----------------------------------------------------------------------------+
+| Security Researcher(s)                                                      |
++:===================================:+:=====================================:+
+| Name                                | **Email address**                     |
++-------------------------------------+---------------------------------------+
+| Raffaele Bova                       | labs-advisory@nozominetworks.com      |
++-------------------------------------+---------------------------------------+
+
+**\**
+
+Libwebsockes is a C library that provides client and server
+implementation for various protocols (e.g., HTTP, websockets, MQTT) and
+more.
+
+Nozomi Networks Lab discovered a "CWE-121: Stack-based Buffer Overflow"
+in the latest software version of libwebsockets, specifically in the
+async-dns component.
+
+The vulnerability allows an attacker that can inspect DNS requests made
+by the victim (e.g. being in the same wireless network) to forge a DNS
+response packet that overflows the stack and may lead to arbitrary code
+execution (depending on the platform and compiler options).
+
+The issue resides in `lws_adns_parse_label` function in
+`lib/system/async-dns/async-dns-parse.c`; this function iteratively parses
+a label however it does not correctly check the number of bytes written
+in the destination buffer.
+
+Specifically, the size of the dest output buffer is specified in the `dl`
+argument, however during the read of each substring of the label only
+the length of the current substring of the label is accounted for not
+overflowing the destination buffer, but previous reads are not accounted
+for.
+
+This means that a label of arbitrary size and content can be supplied
+and is copied onto the stack, however it must be split into substrings
+of size less than `dl`.
+
+To trigger the vulnerability an attacker must be able to sniff the DNS
+request packet to send a response with a matching identifier, otherwise
+the implantation correctly ignores the response.
+
+We have provided a harness for testing, for ease of use copy the harness
+in a subdirectory, for example in minimal-examples-lowlevel/api-tests/,
+and build it
+
+```
+cmake -B build -DLWS_WITH_SYS_ASYNC_DNS=1 -DLWS_WITH_SSL=0
+-DCMAKE_C_FLAGS="-fsanitize=address" . && make -C build lws-test-async-dns
+```
+
+Then it can be run `./build/bin/lws-test-async-dns < poc_stackbof`
+
+![Address sanitizer report of stack buffer overflow](./NN-2025-0103_image.png)
+
+We suggest keeping track of the number of bytes currently written on the
+dest buffer, this could be done by saving the original dest pointer,
+decrementing dl on each substring memcpy, or using an auxiliary
+variable.
+
+CVE: CVE-2025-11678
+Upstream-Status: Backport [https://github.com/warmcat/libwebsockets/commit/2bb9598562b37c942ba5b04bcde3f7fdf66a9d3a]
+
+Signed-off-by: Hugo SIMELIERE <hsimeliere.opensource@witekio.com>
+---
+ lib/system/async-dns/async-dns-parse.c | 5 +++--
+ 1 file changed, 3 insertions(+), 2 deletions(-)
+
+diff --git a/lib/system/async-dns/async-dns-parse.c b/lib/system/async-dns/async-dns-parse.c
+index bdfe2050..81743b3f 100644
+--- a/lib/system/async-dns/async-dns-parse.c
++++ b/lib/system/async-dns/async-dns-parse.c
+@@ -35,7 +35,7 @@ lws_adns_parse_label(const uint8_t *pkt, int len, const uint8_t *ls, int budget,
+        const uint8_t *e = pkt + len, *ols = ls;
+        char pointer = 0, first = 1;
+        uint8_t ll;
+-       int n;
++       int n, readsize = 0;
+ 
+        if (budget < 1)
+                return 0;
+@@ -88,7 +88,7 @@ again1:
+                return -1;
+        }
+ 
+-       if ((unsigned int)ll + 2 > dl) {
++       if ((unsigned int)(ll + 2 + readsize) > dl) {
+                lwsl_notice("%s: qname too large\n", __func__);
+ 
+                return -1;
+@@ -101,6 +101,7 @@ again1:
+        (*dest)[ll + 1] = '\0';
+        *dest += ll + 1;
+        ls += ll;
++       readsize += ll + 1;
+ 
+        if (pointer) {
+                if (*ls)
+-- 
+2.43.0
+
diff --git a/meta-oe/recipes-connectivity/libwebsockets/libwebsockets_4.3.5.bb b/meta-oe/recipes-connectivity/libwebsockets/libwebsockets_4.3.5.bb
index 0b74adf990..cd69281833 100644
--- a/meta-oe/recipes-connectivity/libwebsockets/libwebsockets_4.3.5.bb
+++ b/meta-oe/recipes-connectivity/libwebsockets/libwebsockets_4.3.5.bb
@@ -11,6 +11,7 @@ SRC_URI = "git://github.com/warmcat/libwebsockets.git;protocol=https;branch=v4.3
            file://0001-sll_protocol-may-be-be16.patch \
            file://0002-allow-build-with-cmake-4.patch \
            file://CVE-2025-11677.patch \
+           file://CVE-2025-11678.patch \
            "
 
 UPSTREAM_CHECK_URI = "https://github.com/warmcat/${BPN}/releases"