From b617158dc096709d8600c53b6052144d12b89fab Mon Sep 17 00:00:00 2001 From: Eric Dumazet Date: Fri, 19 Jul 2019 11:52:33 -0700 Subject: tcp: be more careful in tcp_fragment() Some applications set tiny SO_SNDBUF values and expect TCP to just work. Recent patches to address CVE-2019-11478 broke them in case of losses, since retransmits might be prevented. We should allow these flows to make progress. This patch allows the first and last skb in retransmit queue to be split even if memory limits are hit. It also adds the some room due to the fact that tcp_sendmsg() and tcp_sendpage() might overshoot sk_wmem_queued by about one full TSO skb (64KB size). Note this allowance was already present in stable backports for kernels < 4.15 Note for < 4.15 backports : tcp_rtx_queue_tail() will probably look like : static inline struct sk_buff *tcp_rtx_queue_tail(const struct sock *sk) { struct sk_buff *skb = tcp_send_head(sk); return skb ? tcp_write_queue_prev(sk, skb) : tcp_write_queue_tail(sk); } Fixes: f070ef2ac667 ("tcp: tcp_fragment() should apply sane memory limits") Signed-off-by: Eric Dumazet Reported-by: Andrew Prout Tested-by: Andrew Prout Tested-by: Jonathan Lemon Tested-by: Michal Kubecek Acked-by: Neal Cardwell Acked-by: Yuchung Cheng Acked-by: Christoph Paasch Cc: Jonathan Looney Signed-off-by: David S. Miller --- include/net/tcp.h | 5 +++++ 1 file changed, 5 insertions(+) (limited to 'include/net/tcp.h') diff --git a/include/net/tcp.h b/include/net/tcp.h index f42d300f0cfa..e5cf514ba118 100644 --- a/include/net/tcp.h +++ b/include/net/tcp.h @@ -1709,6 +1709,11 @@ static inline struct sk_buff *tcp_rtx_queue_head(const struct sock *sk) return skb_rb_first(&sk->tcp_rtx_queue); } +static inline struct sk_buff *tcp_rtx_queue_tail(const struct sock *sk) +{ + return skb_rb_last(&sk->tcp_rtx_queue); +} + static inline struct sk_buff *tcp_write_queue_head(const struct sock *sk) { return skb_peek(&sk->sk_write_queue); -- cgit v1.2.2 From 95fa145479fbc0a0c1fd3274ceb42ec03c042a4a Mon Sep 17 00:00:00 2001 From: John Fastabend Date: Fri, 19 Jul 2019 10:29:22 -0700 Subject: bpf: sockmap/tls, close can race with map free When a map free is called and in parallel a socket is closed we have two paths that can potentially reset the socket prot ops, the bpf close() path and the map free path. This creates a problem with which prot ops should be used from the socket closed side. If the map_free side completes first then we want to call the original lowest level ops. However, if the tls path runs first we want to call the sockmap ops. Additionally there was no locking around prot updates in TLS code paths so the prot ops could be changed multiple times once from TLS path and again from sockmap side potentially leaving ops pointed at either TLS or sockmap when psock and/or tls context have already been destroyed. To fix this race first only update ops inside callback lock so that TLS, sockmap and lowest level all agree on prot state. Second and a ULP callback update() so that lower layers can inform the upper layer when they are being removed allowing the upper layer to reset prot ops. This gets us close to allowing sockmap and tls to be stacked in arbitrary order but will save that patch for *next trees. v4: - make sure we don't free things for device; - remove the checks which swap the callbacks back only if TLS is at the top. Reported-by: syzbot+06537213db7ba2745c4a@syzkaller.appspotmail.com Fixes: 02c558b2d5d6 ("bpf: sockmap, support for msg_peek in sk_msg with redirect ingress") Signed-off-by: John Fastabend Signed-off-by: Jakub Kicinski Reviewed-by: Dirk van der Merwe Signed-off-by: Daniel Borkmann --- include/net/tcp.h | 3 +++ 1 file changed, 3 insertions(+) (limited to 'include/net/tcp.h') diff --git a/include/net/tcp.h b/include/net/tcp.h index f42d300f0cfa..c82a23470081 100644 --- a/include/net/tcp.h +++ b/include/net/tcp.h @@ -2103,6 +2103,8 @@ struct tcp_ulp_ops { /* initialize ulp */ int (*init)(struct sock *sk); + /* update ulp */ + void (*update)(struct sock *sk, struct proto *p); /* cleanup ulp */ void (*release)(struct sock *sk); @@ -2114,6 +2116,7 @@ void tcp_unregister_ulp(struct tcp_ulp_ops *type); int tcp_set_ulp(struct sock *sk, const char *name); void tcp_get_available_ulp(char *buf, size_t len); void tcp_cleanup_ulp(struct sock *sk); +void tcp_update_ulp(struct sock *sk, struct proto *p); #define MODULE_ALIAS_TCP_ULP(name) \ __MODULE_INFO(alias, alias_userspace, name); \ -- cgit v1.2.2