s390/pkey: fix memory leak within _copy_apqns_from_user()

Fixes: f2bbc96e ("s390/pkey: add CCA AES cipher key support")
Reported-by: Markus Elfring <Markus.Elfring@web.de>
Reported-by: Christian Borntraeger <borntraeger@de.ibm.com>
Signed-off-by: Heiko Carstens <heiko.carstens@de.ibm.com>
Signed-off-by: Vasily Gorbik <gor@linux.ibm.com>

drivers/s390/crypto/pkey_api.c

@@ -740,9 +740,11 @@ static void *_copy_apqns_from_user(void __user *uapqns, size_t nr_apqns)
 		kapqns = kmalloc(nbytes, GFP_KERNEL);
 		if (!kapqns)
 			return ERR_PTR(-ENOMEM);
-		if (copy_from_user(kapqns, uapqns, nbytes))
+		if (copy_from_user(kapqns, uapqns, nbytes)) {
+			kfree(kapqns);
 			return ERR_PTR(-EFAULT);
 		}
+	}
 
 	return kapqns;
 }