From 3ef7cf57c72f32f61e97f8fa401bc39ea1f1a5d4 Mon Sep 17 00:00:00 2001 From: Eric Dumazet Date: Wed, 23 Oct 2019 22:44:50 -0700 Subject: net: use skb_queue_empty_lockless() in poll() handlers Many poll() handlers are lockless. Using skb_queue_empty_lockless() instead of skb_queue_empty() is more appropriate. Signed-off-by: Eric Dumazet Signed-off-by: David S. Miller --- net/sctp/socket.c | 4 ++-- 1 file changed, 2 insertions(+), 2 deletions(-) (limited to 'net/sctp') diff --git a/net/sctp/socket.c b/net/sctp/socket.c index 5ca0ec0e823c..cfb25391b8b0 100644 --- a/net/sctp/socket.c +++ b/net/sctp/socket.c @@ -8476,7 +8476,7 @@ __poll_t sctp_poll(struct file *file, struct socket *sock, poll_table *wait) mask = 0; /* Is there any exceptional events? */ - if (sk->sk_err || !skb_queue_empty(&sk->sk_error_queue)) + if (sk->sk_err || !skb_queue_empty_lockless(&sk->sk_error_queue)) mask |= EPOLLERR | (sock_flag(sk, SOCK_SELECT_ERR_QUEUE) ? EPOLLPRI : 0); if (sk->sk_shutdown & RCV_SHUTDOWN) @@ -8485,7 +8485,7 @@ __poll_t sctp_poll(struct file *file, struct socket *sock, poll_table *wait) mask |= EPOLLHUP; /* Is it readable? Reconsider this code with TCP-style support. */ - if (!skb_queue_empty(&sk->sk_receive_queue)) + if (!skb_queue_empty_lockless(&sk->sk_receive_queue)) mask |= EPOLLIN | EPOLLRDNORM; /* The association is either gone or not ready. */ -- cgit v1.2.3 From 3f926af3f4d688e2e11e7f8ed04e277a14d4d4a4 Mon Sep 17 00:00:00 2001 From: Eric Dumazet Date: Wed, 23 Oct 2019 22:44:51 -0700 Subject: net: use skb_queue_empty_lockless() in busy poll contexts Busy polling usually runs without locks. Let's use skb_queue_empty_lockless() instead of skb_queue_empty() Also uses READ_ONCE() in __skb_try_recv_datagram() to address a similar potential problem. Signed-off-by: Eric Dumazet Signed-off-by: David S. Miller --- net/sctp/socket.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) (limited to 'net/sctp') diff --git a/net/sctp/socket.c b/net/sctp/socket.c index cfb25391b8b0..ca81e06df165 100644 --- a/net/sctp/socket.c +++ b/net/sctp/socket.c @@ -8871,7 +8871,7 @@ struct sk_buff *sctp_skb_recv_datagram(struct sock *sk, int flags, if (sk_can_busy_loop(sk)) { sk_busy_loop(sk, noblock); - if (!skb_queue_empty(&sk->sk_receive_queue)) + if (!skb_queue_empty_lockless(&sk->sk_receive_queue)) continue; } -- cgit v1.2.3 From a904a0693c189691eeee64f6c6b188bd7dc244e9 Mon Sep 17 00:00:00 2001 From: Eric Dumazet Date: Fri, 1 Nov 2019 10:32:19 -0700 Subject: inet: stop leaking jiffies on the wire Historically linux tried to stick to RFC 791, 1122, 2003 for IPv4 ID field generation. RFC 6864 made clear that no matter how hard we try, we can not ensure unicity of IP ID within maximum lifetime for all datagrams with a given source address/destination address/protocol tuple. Linux uses a per socket inet generator (inet_id), initialized at connection startup with a XOR of 'jiffies' and other fields that appear clear on the wire. Thiemo Nagel pointed that this strategy is a privacy concern as this provides 16 bits of entropy to fingerprint devices. Let's switch to a random starting point, this is just as good as far as RFC 6864 is concerned and does not leak anything critical. Fixes: 1da177e4c3f4 ("Linux-2.6.12-rc2") Signed-off-by: Eric Dumazet Reported-by: Thiemo Nagel Signed-off-by: David S. Miller --- net/sctp/socket.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) (limited to 'net/sctp') diff --git a/net/sctp/socket.c b/net/sctp/socket.c index ca81e06df165..ffd3262b7a41 100644 --- a/net/sctp/socket.c +++ b/net/sctp/socket.c @@ -9306,7 +9306,7 @@ void sctp_copy_sock(struct sock *newsk, struct sock *sk, newinet->inet_rcv_saddr = inet->inet_rcv_saddr; newinet->inet_dport = htons(asoc->peer.port); newinet->pmtudisc = inet->pmtudisc; - newinet->inet_id = asoc->next_tsn ^ jiffies; + newinet->inet_id = prandom_u32(); newinet->uc_ttl = inet->uc_ttl; newinet->mc_loop = 1; -- cgit v1.2.3