From: Eric Dumazet edumazet@google.com
[ 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@google.com Cc: David Howells dhowells@redhat.com Signed-off-by: David S. Miller davem@davemloft.net Signed-off-by: Sasha Levin sashal@kernel.org --- 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;