Reviewed-by: Alex Hung <alex.h...@amd.com>
On 5/25/25 20:37, Wentao Liang wrote:
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: sta...@vger.kernel.org # v5.8
Signed-off-by: Wentao Liang <vu...@iscas.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));