From: Colin Ian King <[email protected]>
The recent commit 6c63e6e14da7 ("drm/i915/hdcp: No HDCP when encoder
is't initialized") added a null pointer check on connector->encoder
hence implying that it could potentially be null. This means that
the initialization of dig_port via the call intel_attached_dig_port
may cause a null pointer dereference on connector->encoder. Fix
this by only assigning dig_port after a null check has been performed
on connector->encoder.
Addresses-Coverity: ("Dereference before null check")
Fixes: 36e5e7042b20 ("drm/i915: Don't fully disable HDCP on a port if multiple pipes are using it")
Signed-off-by: Colin Ian King <[email protected]>
---
drivers/gpu/drm/i915/display/intel_hdcp.c | 3 ++-
1 file changed, 2 insertions(+), 1 deletion(-)
diff --git a/drivers/gpu/drm/i915/display/intel_hdcp.c b/drivers/gpu/drm/i915/display/intel_hdcp.c
index ae1371c36a32..7525ea31766c 100644
--- a/drivers/gpu/drm/i915/display/intel_hdcp.c
+++ b/drivers/gpu/drm/i915/display/intel_hdcp.c
@@ -2260,7 +2260,7 @@ int intel_hdcp_enable(struct intel_connector *connector,
const struct intel_crtc_state *pipe_config, u8 content_type)
{
struct drm_i915_private *dev_priv = to_i915(connector->base.dev);
- struct intel_digital_port *dig_port = intel_attached_dig_port(connector);
+ struct intel_digital_port *dig_port;
struct intel_hdcp *hdcp = &connector->hdcp;
unsigned long check_link_interval = DRM_HDCP_CHECK_PERIOD_MS;
int ret = -EINVAL;
@@ -2274,6 +2274,7 @@ int intel_hdcp_enable(struct intel_connector *connector,
return -ENODEV;
}
+ dig_port = intel_attached_dig_port(connector);
mutex_lock(&hdcp->mutex);
mutex_lock(&dig_port->hdcp_mutex);
drm_WARN_ON(&dev_priv->drm,
--
2.30.0
> -----Original Message-----
> From: Colin King <[email protected]>
> Sent: Wednesday, February 24, 2021 12:49 AM
> To: Jani Nikula <[email protected]>; Joonas Lahtinen
> <[email protected]>; Vivi, Rodrigo <[email protected]>;
> David Airlie <[email protected]>; Daniel Vetter <[email protected]>; C, Ramalingam
> <[email protected]>; Gupta, Anshuman <[email protected]>;
> [email protected]; [email protected]
> Cc: [email protected]; [email protected]
> Subject: [PATCH][next] drm/i915/hdcp: Fix null pointer dereference of
> connector->encoder
>
> From: Colin Ian King <[email protected]>
>
> The recent commit 6c63e6e14da7 ("drm/i915/hdcp: No HDCP when encoder is't
> initialized") added a null pointer check on connector->encoder hence implying
> that it could potentially be null. This means that the initialization of dig_port via
> the call intel_attached_dig_port may cause a null pointer dereference on
> connector->encoder. Fix this by only assigning dig_port after a null check has
> been performed on connector->encoder.
>
> Addresses-Coverity: ("Dereference before null check")
> Fixes: 36e5e7042b20 ("drm/i915: Don't fully disable HDCP on a port if multiple
> pipes are using it")
> Signed-off-by: Colin Ian King <[email protected]>
Looks good to me.
Reviewed-by: Anshuman Gupta <[email protected]>
> ---
> drivers/gpu/drm/i915/display/intel_hdcp.c | 3 ++-
> 1 file changed, 2 insertions(+), 1 deletion(-)
>
> diff --git a/drivers/gpu/drm/i915/display/intel_hdcp.c
> b/drivers/gpu/drm/i915/display/intel_hdcp.c
> index ae1371c36a32..7525ea31766c 100644
> --- a/drivers/gpu/drm/i915/display/intel_hdcp.c
> +++ b/drivers/gpu/drm/i915/display/intel_hdcp.c
> @@ -2260,7 +2260,7 @@ int intel_hdcp_enable(struct intel_connector
> *connector,
> const struct intel_crtc_state *pipe_config, u8 content_type)
> {
> struct drm_i915_private *dev_priv = to_i915(connector->base.dev);
> - struct intel_digital_port *dig_port =
> intel_attached_dig_port(connector);
> + struct intel_digital_port *dig_port;
> struct intel_hdcp *hdcp = &connector->hdcp;
> unsigned long check_link_interval = DRM_HDCP_CHECK_PERIOD_MS;
> int ret = -EINVAL;
> @@ -2274,6 +2274,7 @@ int intel_hdcp_enable(struct intel_connector
> *connector,
> return -ENODEV;
> }
>
> + dig_port = intel_attached_dig_port(connector);
> mutex_lock(&hdcp->mutex);
> mutex_lock(&dig_port->hdcp_mutex);
> drm_WARN_ON(&dev_priv->drm,
> --
> 2.30.0