linux-kernel - [PATCH] drm/amd/display: Add null pointer check for get_first_active

lists.openwall.net		lists / announce owl-users owl-dev john-users john-dev passwdqc-users yescrypt popa3d-users / oss-security kernel-hardening musl sabotage tlsify passwords / crypt-dev xvendor / Bugtraq Full-Disclosure linux-kernel linux-netdev linux-ext4 linux-hardening linux-cve-announce PHC
Open Source and information security mailing list archives

Hash Suite: Windows password security audit tool. GUI, reports in PDF.

[<prev] [next>] [thread-next>] [day] [month] [year] [list]

Message-ID: <20250526023732.325-1-vulab@iscas.ac.cn>
Date: Mon, 26 May 2025 10:37:31 +0800
From: Wentao Liang <vulab@...as.ac.cn>
To: harry.wentland@....com,
	sunpeng.li@....com,
	Rodrigo.Siqueira@....com,
	alexander.deucher@....com,
	christian.koenig@....com,
	Xinhui.Pan@....com,
	crypto@...r.kernel.org,
	airlied@...il.com,
	simona@...ll.ch
Cc: alex.hung@....com,
	amd-gfx@...ts.freedesktop.org,
	dri-devel@...ts.freedesktop.org,
	linux-kernel@...r.kernel.org,
	Wentao Liang <vulab@...as.ac.cn>,
	stable@...r.kernel.org
Subject: [PATCH] drm/amd/display: Add null pointer check for get_first_active_display()

The function mod_hdcp_hdcp1_enable_encryption() calls the function
get_first_active_display(), but does not check its return value.
The return value is a null pointer if the display list is empty.
This will lead to a null pointer dereference in
mod_hdcp_hdcp2_enable_encryption().

Add a null pointer check for get_first_active_display() and return
MOD_HDCP_STATUS_DISPLAY_NOT_FOUND if the function return null.

Fixes: 2deade5ede56 ("drm/amd/display: Remove hdcp display state with mst fix")
Cc: stable@...r.kernel.org # v5.8
Signed-off-by: Wentao Liang <vulab@...as.ac.cn>
---
 drivers/gpu/drm/amd/display/modules/hdcp/hdcp_psp.c | 3 +++
 1 file changed, 3 insertions(+)

diff --git a/drivers/gpu/drm/amd/display/modules/hdcp/hdcp_psp.c b/drivers/gpu/drm/amd/display/modules/hdcp/hdcp_psp.c
index 8c137d7c032e..e58e7b93810b 100644
--- a/drivers/gpu/drm/amd/display/modules/hdcp/hdcp_psp.c
+++ b/drivers/gpu/drm/amd/display/modules/hdcp/hdcp_psp.c
@@ -368,6 +368,9 @@ enum mod_hdcp_status mod_hdcp_hdcp1_enable_encryption(struct mod_hdcp *hdcp)
 	struct mod_hdcp_display *display = get_first_active_display(hdcp);
 	enum mod_hdcp_status status = MOD_HDCP_STATUS_SUCCESS;
 
+	if (!display)
+		return MOD_HDCP_STATUS_DISPLAY_NOT_FOUND;
+
 	mutex_lock(&psp->hdcp_context.mutex);
 	hdcp_cmd = (struct ta_hdcp_shared_memory *)psp->hdcp_context.context.mem_context.shared_buf;
 	memset(hdcp_cmd, 0, sizeof(struct ta_hdcp_shared_memory));
-- 
2.42.0.windows.2