ssb: Fix potential NULL pointer dereference in ssb_device_uevent()

The ssb_device_uevent() function first attempts to convert the 'dev' pointer
to 'struct ssb_device *'. However, it mistakenly dereferences 'dev' before
performing the NULL check, potentially leading to a NULL pointer
dereference if 'dev' is NULL.

To fix this issue, move the NULL check before dereferencing the 'dev' pointer,
ensuring that the pointer is valid before attempting to use it.

Found by Linux Verification Center (linuxtesting.org) with SVACE.

Signed-off-by: Rand Deeb <rand.sec96@gmail.com>
Signed-off-by: Kalle Valo <kvalo@kernel.org>
Link: https://msgid.link/20240306123028.164155-1-rand.sec96@gmail.com

diff --git a/drivers/ssb/main.c b/drivers/ssb/main.c
index 9f30e0edadfe294337079c639bce7e5b5f8d72ad..bdb6595ffd2d5194ddee2fe0e9f692bf2deeceb1 100644 (file)
--- a/drivers/ssb/main.c
+++ b/drivers/ssb/main.c
@@ -341,11 +341,13 @@ static int ssb_bus_match(struct device *dev, struct device_driver *drv)
 
 static int ssb_device_uevent(const struct device *dev, struct kobj_uevent_env *env)
 {
-       const struct ssb_device *ssb_dev = dev_to_ssb_dev(dev);
+       const struct ssb_device *ssb_dev;
 
        if (!dev)
                return -ENODEV;
 
+       ssb_dev = dev_to_ssb_dev(dev);
+
        return add_uevent_var(env,
                             "MODALIAS=ssb:v%04Xid%04Xrev%02X",
                             ssb_dev->id.vendor, ssb_dev->id.coreid,