linux-kernel - [PATCH v2] misc/mei: Add NULL check to component match callback functions

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Message-Id: <20220330204809.2061497-1-wonchung@google.com>
Date:   Wed, 30 Mar 2022 20:48:09 +0000
From:   Won Chung <wonchung@...gle.com>
To:     Tomas Winkler <tomas.winkler@...el.com>
Cc:     Heikki Krogerus <heikki.krogerus@...ux.intel.com>,
        Mika Westerberg <mika.westerberg@...ux.intel.com>,
        Benson Leung <bleung@...gle.com>,
        Prashant Malani <pmalani@...gle.com>,
        linux-kernel@...r.kernel.org, stable@...r.kernel.org,
        Won Chung <wonchung@...gle.com>
Subject: [PATCH v2] misc/mei: Add NULL check to component match callback functions

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")
Signed-off-by: Heikki Krogerus <heikki.krogerus@...ux.intel.com>
Signed-off-by: Mika Westerberg <mika.westerberg@...ux.intel.com>
Signed-off-by: Won Chung <wonchung@...gle.com>
---
Changes from v1:
- Add "Fixes" tag
- Send to stable@...r.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