[PATCH v3] misc/mei: Add NULL check to component match callback functions

Won Chung
2022-03-31T08:49:54Z

Component match callback functions need to check if expected data is
passed to them. Without this check, it can cause a NULL pointer
dereference when another driver registers a component before i915
drivers have their component master fully bind.

Fixes: 1e8d19d9b0dfc ("mei: hdcp: bind only with i915 on the same PCH")
Fixes: c2004ce99ed73 ("mei: pxp: export pavp client to me client bus")
Suggested-by: Heikki Krogerus <heikki.krogerus@linux.intel.com>
Suggested-by: Mika Westerberg <mika.westerberg@linux.intel.com>
Signed-off-by: Won Chung <wonchung@google.com>
Cc: stable@vger.kernel.org
---
Changes from v2:
- Correctly add "Suggested-by" tag
- Add "Cc: stable@vger.kernel.org"

Changes from v1:
- Add "Fixes" tag
- Send to stable@vger.kernel.org

drivers/misc/mei/hdcp/mei_hdcp.c | 2 +-
drivers/misc/mei/pxp/mei_pxp.c | 2 +-
2 files changed, 2 insertions(+), 2 deletions(-)

diff --git a/drivers/misc/mei/hdcp/mei_hdcp.c b/drivers/misc/mei/hdcp/mei_hdcp.c
index ec2a4fce8581..843dbc2b21b1 100644
--- a/drivers/misc/mei/hdcp/mei_hdcp.c
+++ b/drivers/misc/mei/hdcp/mei_hdcp.c
@@ -784,7 +784,7 @@ static int mei_hdcp_component_match(struct device *dev, int subcomponent,
{
struct device *base = data;

- if (strcmp(dev->driver->name, "i915") ||
+ if (!base || !dev->driver || strcmp(dev->driver->name, "i915") ||
subcomponent != I915_COMPONENT_HDCP)
return 0;

diff --git a/drivers/misc/mei/pxp/mei_pxp.c b/drivers/misc/mei/pxp/mei_pxp.c
index f7380d387bab..e32a81da8af6 100644
--- a/drivers/misc/mei/pxp/mei_pxp.c
+++ b/drivers/misc/mei/pxp/mei_pxp.c
@@ -131,7 +131,7 @@ static int mei_pxp_component_match(struct device *dev, int subcomponent,
{
struct device *base = data;

- if (strcmp(dev->driver->name, "i915") ||
+ if (!base || !dev->driver || strcmp(dev->driver->name, "i915") ||
subcomponent != I915_COMPONENT_PXP)
return 0;

--
2.35.1.1021.g381101b075-goog