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authorDavid S. Miller <davem@davemloft.net>2014-04-11 16:15:36 -0400
committerDavid S. Miller <davem@davemloft.net>2014-04-11 16:15:36 -0400
commit676d23690fb62b5d51ba5d659935e9f7d9da9f8e (patch)
treef6fbceee43e05c724868153ca37b702fb5e43b8c /net/tipc/socket.c
parentad20d5f673898578f9d8a156d7a4c921f5ca4584 (diff)
net: Fix use after free by removing length arg from sk_data_ready callbacks.
Several spots in the kernel perform a sequence like: skb_queue_tail(&sk->s_receive_queue, skb); sk->sk_data_ready(sk, skb->len); But at the moment we place the SKB onto the socket receive queue it can be consumed and freed up. So this skb->len access is potentially to freed up memory. Furthermore, the skb->len can be modified by the consumer so it is possible that the value isn't accurate. And finally, no actual implementation of this callback actually uses the length argument. And since nobody actually cared about it's value, lots of call sites pass arbitrary values in such as '0' and even '1'. So just remove the length argument from the callback, that way there is no confusion whatsoever and all of these use-after-free cases get fixed as a side effect. Based upon a patch by Eric Dumazet and his suggestion to audit this issue tree-wide. Signed-off-by: David S. Miller <davem@davemloft.net>
Diffstat (limited to 'net/tipc/socket.c')
-rw-r--r--net/tipc/socket.c6
1 files changed, 3 insertions, 3 deletions
diff --git a/net/tipc/socket.c b/net/tipc/socket.c
index adc12e227303..3c0256962f7d 100644
--- a/net/tipc/socket.c
+++ b/net/tipc/socket.c
@@ -45,7 +45,7 @@
#define CONN_TIMEOUT_DEFAULT 8000 /* default connect timeout = 8s */
static int backlog_rcv(struct sock *sk, struct sk_buff *skb);
-static void tipc_data_ready(struct sock *sk, int len);
+static void tipc_data_ready(struct sock *sk);
static void tipc_write_space(struct sock *sk);
static int tipc_release(struct socket *sock);
static int tipc_accept(struct socket *sock, struct socket *new_sock, int flags);
@@ -1248,7 +1248,7 @@ static void tipc_write_space(struct sock *sk)
* @sk: socket
* @len: the length of messages
*/
-static void tipc_data_ready(struct sock *sk, int len)
+static void tipc_data_ready(struct sock *sk)
{
struct socket_wq *wq;
@@ -1410,7 +1410,7 @@ static u32 filter_rcv(struct sock *sk, struct sk_buff *buf)
__skb_queue_tail(&sk->sk_receive_queue, buf);
skb_set_owner_r(buf, sk);
- sk->sk_data_ready(sk, 0);
+ sk->sk_data_ready(sk);
return TIPC_OK;
}