From b48732e4a48d80ed4a14812f0bab09560846514e Mon Sep 17 00:00:00 2001 From: Mark Salyzyn Date: Tue, 26 May 2015 08:22:19 -0700 Subject: [PATCH] unix/caif: sk_socket can disappear when state is unlocked got a rare NULL pointer dereference in clear_bit Signed-off-by: Mark Salyzyn Acked-by: Hannes Frederic Sowa ---- v2: switch to sock_flag(sk, SOCK_DEAD) and added net/caif/caif_socket.c v3: return -ECONNRESET in upstream caller of wait function for SOCK_DEAD Signed-off-by: David S. Miller --- net/caif/caif_socket.c | 8 ++++++++ net/unix/af_unix.c | 8 ++++++++ 2 files changed, 16 insertions(+) diff --git a/net/caif/caif_socket.c b/net/caif/caif_socket.c index 4ec0c803aef1..112ad784838a 100644 --- a/net/caif/caif_socket.c +++ b/net/caif/caif_socket.c @@ -330,6 +330,10 @@ static long caif_stream_data_wait(struct sock *sk, long timeo) release_sock(sk); timeo = schedule_timeout(timeo); lock_sock(sk); + + if (sock_flag(sk, SOCK_DEAD)) + break; + clear_bit(SOCK_ASYNC_WAITDATA, &sk->sk_socket->flags); } @@ -373,6 +377,10 @@ static int caif_stream_recvmsg(struct socket *sock, struct msghdr *msg, struct sk_buff *skb; lock_sock(sk); + if (sock_flag(sk, SOCK_DEAD)) { + err = -ECONNRESET; + goto unlock; + } skb = skb_dequeue(&sk->sk_receive_queue); caif_check_flow_release(sk); diff --git a/net/unix/af_unix.c b/net/unix/af_unix.c index 5266ea7b922b..06430598cf51 100644 --- a/net/unix/af_unix.c +++ b/net/unix/af_unix.c @@ -1880,6 +1880,10 @@ static long unix_stream_data_wait(struct sock *sk, long timeo, unix_state_unlock(sk); timeo = freezable_schedule_timeout(timeo); unix_state_lock(sk); + + if (sock_flag(sk, SOCK_DEAD)) + break; + clear_bit(SOCK_ASYNC_WAITDATA, &sk->sk_socket->flags); } @@ -1939,6 +1943,10 @@ static int unix_stream_recvmsg(struct socket *sock, struct msghdr *msg, struct sk_buff *skb, *last; unix_state_lock(sk); + if (sock_flag(sk, SOCK_DEAD)) { + err = -ECONNRESET; + goto unlock; + } last = skb = skb_peek(&sk->sk_receive_queue); again: if (skb == NULL) {