From 9ecf8ba763d0ffe0673538eb4bf7806f20455d19 Mon Sep 17 00:00:00 2001 From: John Harrison Date: Thu, 23 Jul 2026 15:06:52 -0700 Subject: [PATCH] drm/connector/hdmi: Fix out of bounds memory read MIME-Version: 1.0 Content-Type: text/plain; charset=utf8 Content-Transfer-Encoding: 8bit A helper function was copying a given audio infoframe into the connector's copy but using the size of the destination (a generic target, sized to accept many different data blocks) not the source (a very specific type of data block). Thus, it was copying 60 bytes of data from a 28 byte allocation. Fix that by using the source size instead, together with a build bug on the source size actually being smaller than the destination. I hit this running KUnit tests under KASAN (while debugging something else entirely). In the real world, it seems unlikely to cause an actual problem. It is a read not a write so it can't corrupt any memory. However, it could potentially fall off the end of a page and cause an accvio bug. Fixes: f378b77227bc ("drm/connector: hdmi: Add Infoframes generation") Cc: Ville Syrjälä Cc: Dmitry Baryshkov Cc: Maxime Ripard Cc: Maarten Lankhorst Cc: Thomas Zimmermann Cc: David Airlie Cc: Simona Vetter Cc: Dmitry Baryshkov Cc: Daniel Stone Cc: Nicolas Frattaroli Cc: Jani Nikula Cc: José Expósito Cc: Laurent Pinchart Cc: dri-devel@lists.freedesktop.org Cc: stable@vger.kernel.org # v6.11+ Signed-off-by: John Harrison Link: https://patch.msgid.link/20260723220652.533345-1-John.Harrison@Igalia.com Signed-off-by: Maxime Ripard --- drivers/gpu/drm/display/drm_hdmi_state_helper.c | 3 ++- 1 file changed, 2 insertions(+), 1 deletion(-) diff --git a/drivers/gpu/drm/display/drm_hdmi_state_helper.c b/drivers/gpu/drm/display/drm_hdmi_state_helper.c index 4867edbf2622..cae0d85fb440 100644 --- a/drivers/gpu/drm/display/drm_hdmi_state_helper.c +++ b/drivers/gpu/drm/display/drm_hdmi_state_helper.c @@ -1096,7 +1096,8 @@ drm_atomic_helper_connector_hdmi_update_audio_infoframe(struct drm_connector *co mutex_lock(&connector->hdmi.infoframes.lock); - memcpy(&infoframe->data, frame, sizeof(infoframe->data)); + BUILD_BUG_ON(sizeof(*frame) > sizeof(infoframe->data)); + memcpy(&infoframe->data, frame, sizeof(*frame)); infoframe->set = true; ret = write_infoframe(connector, &funcs->audio, "Audio", infoframe); -- 2.30.2