6.6-stable review patch. If anyone has any objections, please let me know.
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From: Wentao Liang vulab@iscas.ac.cn
commit c3e9826a22027a21d998d3e64882fa377b613006 upstream.
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") Signed-off-by: Wentao Liang vulab@iscas.ac.cn Reviewed-by: Alex Hung alex.hung@amd.com Signed-off-by: Alex Deucher alexander.deucher@amd.com Cc: stable@vger.kernel.org # v5.8 Signed-off-by: Greg Kroah-Hartman gregkh@linuxfoundation.org --- drivers/gpu/drm/amd/display/modules/hdcp/hdcp_psp.c | 3 +++ 1 file changed, 3 insertions(+)
--- 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_enab 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));