net/rds: Avoid potential use after free in rds_send_remove_from_sock

In case of rs failure in rds_send_remove_from_sock(), the 'rm' resource is freed and later under spinlock, causing potential use-after-free. Set the free pointer to NULL to avoid undefined behavior. Signed-off-by: Aditya Pakki <pakki001@umn.edu> Acked-by: Santosh Shilimkar <santosh.shilimkar@oracle.com> Signed-off-by: David S. Miller <davem@davemloft.net>
Intel-BMC · Apr 7, 2021 · 0c85a7e · 0c85a7e
1 parent 5219d60
commit 0c85a7e
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diff --git a/net/rds/message.c b/net/rds/message.c
@@ -180,6 +180,7 @@ void rds_message_put(struct rds_message *rm)
 		rds_message_purge(rm);
 
 		kfree(rm);
+		rm = NULL;
 	}
 }
 EXPORT_SYMBOL_GPL(rds_message_put);

diff --git a/net/rds/send.c b/net/rds/send.c
@@ -665,7 +665,7 @@ static void rds_send_remove_from_sock(struct list_head *messages, int status)
 unlock_and_drop:
 		spin_unlock_irqrestore(&rm->m_rs_lock, flags);
 		rds_message_put(rm);
-		if (was_on_sock)
+		if (was_on_sock && rm)
 			rds_message_put(rm);
 	}