[Devel] [PATCH 1/2][INET] Fix potential kfree on vmalloc-ed area of request_sock_queue

[Pavel Emelyanov]

The request_sock_queue's listen_opt is either vmalloc-ed or
kmalloc-ed depending on the number of table entries. Thus it 
is expected to be handled properly on free, which is done in 
the reqsk_queue_destroy().

However the error path in inet_csk_listen_start() calls 
the lite version of reqsk_queue_destroy, called 
__reqsk_queue_destroy, which calls the kfree unconditionally. 

Fix this and move the __reqsk_queue_destroy into a .c file as 
it looks too big to be inline.

Signed-off-by: Pavel Emelyanov <xemul at openvz.org>

---

diff --git a/include/net/request_sock.h b/include/net/request_sock.h
index 7aed02c..0a954ee 100644
--- a/include/net/request_sock.h
+++ b/include/net/request_sock.h
@@ -136,11 +136,7 @@ static inline struct listen_sock *reqsk_queue_yank_listen_sk(struct request_sock
 	return lopt;
 }
 
-static inline void __reqsk_queue_destroy(struct request_sock_queue *queue)
-{
-	kfree(reqsk_queue_yank_listen_sk(queue));
-}
-
+extern void __reqsk_queue_destroy(struct request_sock_queue *queue);
 extern void reqsk_queue_destroy(struct request_sock_queue *queue);
 
 static inline struct request_sock *
diff --git a/net/core/request_sock.c b/net/core/request_sock.c
index 5f0818d..12a15f5 100644
--- a/net/core/request_sock.c
+++ b/net/core/request_sock.c
@@ -71,6 +71,20 @@ int reqsk_queue_alloc(struct request_sock_queue *queue,
 
 EXPORT_SYMBOL(reqsk_queue_alloc);
 
+void __reqsk_queue_destroy(struct request_sock_queue *queue)
+{
+	struct listen_sock *lopt = reqsk_queue_yank_listen_sk(queue);
+	size_t lopt_size = sizeof(struct listen_sock) +
+		lopt->nr_table_entries * sizeof(struct request_sock *);
+
+	if (lopt_size > PAGE_SIZE)
+		vfree(lopt);
+	else
+		kfree(lopt);
+}
+
+EXPORT_SYMBOL(__reqsk_queue_destroy);
+
 void reqsk_queue_destroy(struct request_sock_queue *queue)
 {
 	/* make all the listen_opt local to us */