usb: typec: Make sure an alt mode exist before getting its partner

Heikki Krogerus · gregkh · commit 5f54a85db5df · 2019-06-12T17:13:02.000+02:00
Adding check to typec_altmode_get_partner() to prevent potential NULL pointer dereference. Reported-by: Vladimir Yerilov <openmindead@gmail.com> Fixes: ad74b86 ("usb: typec: ucsi: Preliminary support for alternate modes") Signed-off-by: Heikki Krogerus <heikki.krogerus@linux.intel.com> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
diff --git a/drivers/usb/typec/bus.c b/drivers/usb/typec/bus.c
@@ -192,7 +192,7 @@ EXPORT_SYMBOL_GPL(typec_altmode_vdm);
 const struct typec_altmode *
 typec_altmode_get_partner(struct typec_altmode *adev)
 {
-	return &to_altmode(adev)->partner->adev;
+	return adev ? &to_altmode(adev)->partner->adev : NULL;
 }
 EXPORT_SYMBOL_GPL(typec_altmode_get_partner);
 

Original file line number	Diff line number	Diff line change
`@@ -192,7 +192,7 @@ EXPORT_SYMBOL_GPL(typec_altmode_vdm);`
`192`	`192`	`const struct typec_altmode *`
`193`	`193`	`typec_altmode_get_partner(struct typec_altmode *adev)`
`194`	`194`	`{`
`195`		`- return &to_altmode(adev)->partner->adev;`
	`195`	`+ return adev ? &to_altmode(adev)->partner->adev : NULL;`
`196`	`196`	`}`
`197`	`197`	`EXPORT_SYMBOL_GPL(typec_altmode_get_partner);`
`198`	`198`