From c42253cc88206fd0e9868c8b2fd7f9e79f9e0e03 Mon Sep 17 00:00:00 2001 From: John Fastabend Date: Mon, 13 May 2019 07:19:37 -0700 Subject: bpf: sockmap remove duplicate queue free In tcp bpf remove we free the cork list and purge the ingress msg list. However we do this before the ref count reaches zero so it could be possible some other access is in progress. In this case (tcp close and/or tcp_unhash) we happen to also hold the sock lock so no path exists but lets fix it otherwise it is extremely fragile and breaks the reference counting rules. Also we already check the cork list and ingress msg queue and free them once the ref count reaches zero so its wasteful to check twice. Fixes: 604326b41a6fb ("bpf, sockmap: convert to generic sk_msg interface") Signed-off-by: John Fastabend Signed-off-by: Daniel Borkmann --- net/ipv4/tcp_bpf.c | 2 -- 1 file changed, 2 deletions(-) (limited to 'net/ipv4') diff --git a/net/ipv4/tcp_bpf.c b/net/ipv4/tcp_bpf.c index 1bb7321a256d..4a619c85daed 100644 --- a/net/ipv4/tcp_bpf.c +++ b/net/ipv4/tcp_bpf.c @@ -528,8 +528,6 @@ static void tcp_bpf_remove(struct sock *sk, struct sk_psock *psock) { struct sk_psock_link *link; - sk_psock_cork_free(psock); - __sk_psock_purge_ingress_msg(psock); while ((link = sk_psock_link_pop(psock))) { sk_psock_unlink(sk, link); sk_psock_free_link(link); -- cgit v1.2.3 From 5fa2ca7c4a3fc176f31b495e1a704862d8188b53 Mon Sep 17 00:00:00 2001 From: John Fastabend Date: Mon, 13 May 2019 21:42:03 -0700 Subject: bpf, tcp: correctly handle DONT_WAIT flags and timeo == 0 The tcp_bpf_wait_data() routine needs to check timeo != 0 before calling sk_wait_event() otherwise we may see unexpected stalls on receiver. Arika did all the leg work here I just formatted, posted and ran a few tests. Fixes: 604326b41a6fb ("bpf, sockmap: convert to generic sk_msg interface") Reported-by: Arika Chen Suggested-by: Arika Chen Signed-off-by: John Fastabend Signed-off-by: Daniel Borkmann --- net/ipv4/tcp_bpf.c | 5 ++++- 1 file changed, 4 insertions(+), 1 deletion(-) (limited to 'net/ipv4') diff --git a/net/ipv4/tcp_bpf.c b/net/ipv4/tcp_bpf.c index 4a619c85daed..3d1e15401384 100644 --- a/net/ipv4/tcp_bpf.c +++ b/net/ipv4/tcp_bpf.c @@ -27,7 +27,10 @@ static int tcp_bpf_wait_data(struct sock *sk, struct sk_psock *psock, int flags, long timeo, int *err) { DEFINE_WAIT_FUNC(wait, woken_wake_function); - int ret; + int ret = 0; + + if (!timeo) + return ret; add_wait_queue(sk_sleep(sk), &wait); sk_set_bit(SOCKWQ_ASYNC_WAITDATA, sk); -- cgit v1.2.3