From: Eric Dumazet <edumazet@xxxxxxxxxx>
[ Upstream commit 2ca4f6ca4562594ef161e4140c2a5e0e5282967b ]
We need to extend the rcu_read_lock() section in rxrpc_error_report()
and use rcu_dereference_sk_user_data() instead of plain access
to sk->sk_user_data to make sure all rules are respected.
The compiler wont reload sk->sk_user_data at will, and RCU rules
prevent memory beeing freed too soon.
Fixes: f0308fb07080 ("rxrpc: Fix possible NULL pointer access in ICMP handling")
Fixes: 17926a79320a ("[AF_RXRPC]: Provide secure RxRPC sockets for use by userspace and kernel both")
Signed-off-by: Eric Dumazet <edumazet@xxxxxxxxxx>
Cc: David Howells <dhowells@xxxxxxxxxx>
Signed-off-by: David S. Miller <davem@xxxxxxxxxxxxx>
Signed-off-by: Sasha Levin <sashal@xxxxxxxxxx>
---
net/rxrpc/peer_event.c | 12 ++++++++----
1 file changed, 8 insertions(+), 4 deletions(-)
diff --git a/net/rxrpc/peer_event.c b/net/rxrpc/peer_event.c
index 61451281d74a3..48f67a9b1037c 100644
--- a/net/rxrpc/peer_event.c
+++ b/net/rxrpc/peer_event.c
@@ -147,13 +147,16 @@ void rxrpc_error_report(struct sock *sk)
{
struct sock_exterr_skb *serr;
struct sockaddr_rxrpc srx;
- struct rxrpc_local *local = sk->sk_user_data;
+ struct rxrpc_local *local;
struct rxrpc_peer *peer;
struct sk_buff *skb;
- if (unlikely(!local))
+ rcu_read_lock();
+ local = rcu_dereference_sk_user_data(sk);
+ if (unlikely(!local)) {
+ rcu_read_unlock();
return;
-
+ }
_enter("%p{%d}", sk, local->debug_id);
/* Clear the outstanding error value on the socket so that it doesn't
@@ -163,6 +166,7 @@ void rxrpc_error_report(struct sock *sk)
skb = sock_dequeue_err_skb(sk);
if (!skb) {
+ rcu_read_unlock();
_leave("UDP socket errqueue empty");
return;
}
@@ -170,11 +174,11 @@ void rxrpc_error_report(struct sock *sk)
serr = SKB_EXT_ERR(skb);
if (!skb->len && serr->ee.ee_origin == SO_EE_ORIGIN_TIMESTAMPING) {
_leave("UDP empty message");
+ rcu_read_unlock();
rxrpc_free_skb(skb, rxrpc_skb_freed);
return;
}
- rcu_read_lock();
peer = rxrpc_lookup_peer_icmp_rcu(local, skb, &srx);
if (peer && !rxrpc_get_peer_maybe(peer))
peer = NULL;
--
2.20.1
