From: Mao Wenan <wenan.mao@linux.alibaba.com> To: edumazet@google.com, davem@davemloft.net, kuznet@ms2.inr.ac.ru, yoshfuji@linux-ipv6.org, kuba@kernel.org Cc: netdev@vger.kernel.org, linux-kernel@vger.kernel.org, kernel-janitors@vger.kernel.org, Mao Wenan <wenan.mao@linux.alibaba.com> Subject: [PATCH net v5] net: Update window_clamp if SOCK_RCVBUF is set Date: Tue, 10 Nov 2020 08:16:31 +0800 [thread overview] Message-ID: <1604967391-123737-1-git-send-email-wenan.mao@linux.alibaba.com> (raw) In-Reply-To: <CANn89i+ABLMJTEKat=9=qujNwe0BFavphzqYc1CQGtrdkwUnXg@mail.gmail.com> When net.ipv4.tcp_syncookies=1 and syn flood is happened, cookie_v4_check or cookie_v6_check tries to redo what tcp_v4_send_synack or tcp_v6_send_synack did, rsk_window_clamp will be changed if SOCK_RCVBUF is set, which will make rcv_wscale is different, the client still operates with initial window scale and can overshot granted window, the client use the initial scale but local server use new scale to advertise window value, and session work abnormally. Fixes: e88c64f0a425 ("tcp: allow effective reduction of TCP's rcv-buffer via setsockopt") Signed-off-by: Mao Wenan <wenan.mao@linux.alibaba.com> --- v5: fix variable to adapat to Christmas tree format. v4: change fixes tag format, and delay the actual call to tcp_full_space(). v3: add local variable full_space, add fixes tag. v2: fix for ipv6. net/ipv4/syncookies.c | 9 +++++++-- net/ipv6/syncookies.c | 10 ++++++++-- 2 files changed, 15 insertions(+), 4 deletions(-) diff --git a/net/ipv4/syncookies.c b/net/ipv4/syncookies.c index 6ac473b..00dc3f9 100644 --- a/net/ipv4/syncookies.c +++ b/net/ipv4/syncookies.c @@ -331,7 +331,7 @@ struct sock *cookie_v4_check(struct sock *sk, struct sk_buff *skb) __u32 cookie = ntohl(th->ack_seq) - 1; struct sock *ret = sk; struct request_sock *req; - int mss; + int full_space, mss; struct rtable *rt; __u8 rcv_wscale; struct flowi4 fl4; @@ -427,8 +427,13 @@ struct sock *cookie_v4_check(struct sock *sk, struct sk_buff *skb) /* Try to redo what tcp_v4_send_synack did. */ req->rsk_window_clamp = tp->window_clamp ? :dst_metric(&rt->dst, RTAX_WINDOW); + /* limit the window selection if the user enforce a smaller rx buffer */ + full_space = tcp_full_space(sk); + if (sk->sk_userlocks & SOCK_RCVBUF_LOCK && + (req->rsk_window_clamp > full_space || req->rsk_window_clamp == 0)) + req->rsk_window_clamp = full_space; - tcp_select_initial_window(sk, tcp_full_space(sk), req->mss, + tcp_select_initial_window(sk, full_space, req->mss, &req->rsk_rcv_wnd, &req->rsk_window_clamp, ireq->wscale_ok, &rcv_wscale, dst_metric(&rt->dst, RTAX_INITRWND)); diff --git a/net/ipv6/syncookies.c b/net/ipv6/syncookies.c index e796a64..9b6cae1 100644 --- a/net/ipv6/syncookies.c +++ b/net/ipv6/syncookies.c @@ -136,7 +136,7 @@ struct sock *cookie_v6_check(struct sock *sk, struct sk_buff *skb) __u32 cookie = ntohl(th->ack_seq) - 1; struct sock *ret = sk; struct request_sock *req; - int mss; + int full_space, mss; struct dst_entry *dst; __u8 rcv_wscale; u32 tsoff = 0; @@ -241,7 +241,13 @@ struct sock *cookie_v6_check(struct sock *sk, struct sk_buff *skb) } req->rsk_window_clamp = tp->window_clamp ? :dst_metric(dst, RTAX_WINDOW); - tcp_select_initial_window(sk, tcp_full_space(sk), req->mss, + /* limit the window selection if the user enforce a smaller rx buffer */ + full_space = tcp_full_space(sk); + if (sk->sk_userlocks & SOCK_RCVBUF_LOCK && + (req->rsk_window_clamp > full_space || req->rsk_window_clamp == 0)) + req->rsk_window_clamp = full_space; + + tcp_select_initial_window(sk, full_space, req->mss, &req->rsk_rcv_wnd, &req->rsk_window_clamp, ireq->wscale_ok, &rcv_wscale, dst_metric(dst, RTAX_INITRWND)); -- 1.8.3.1
WARNING: multiple messages have this Message-ID (diff)
From: Mao Wenan <wenan.mao@linux.alibaba.com> To: edumazet@google.com, davem@davemloft.net, kuznet@ms2.inr.ac.ru, yoshfuji@linux-ipv6.org, kuba@kernel.org Cc: netdev@vger.kernel.org, linux-kernel@vger.kernel.org, kernel-janitors@vger.kernel.org, Mao Wenan <wenan.mao@linux.alibaba.com> Subject: [PATCH net v5] net: Update window_clamp if SOCK_RCVBUF is set Date: Tue, 10 Nov 2020 00:16:31 +0000 [thread overview] Message-ID: <1604967391-123737-1-git-send-email-wenan.mao@linux.alibaba.com> (raw) In-Reply-To: <CANn89i+ABLMJTEKat=9=qujNwe0BFavphzqYc1CQGtrdkwUnXg@mail.gmail.com> When net.ipv4.tcp_syncookies=1 and syn flood is happened, cookie_v4_check or cookie_v6_check tries to redo what tcp_v4_send_synack or tcp_v6_send_synack did, rsk_window_clamp will be changed if SOCK_RCVBUF is set, which will make rcv_wscale is different, the client still operates with initial window scale and can overshot granted window, the client use the initial scale but local server use new scale to advertise window value, and session work abnormally. Fixes: e88c64f0a425 ("tcp: allow effective reduction of TCP's rcv-buffer via setsockopt") Signed-off-by: Mao Wenan <wenan.mao@linux.alibaba.com> --- v5: fix variable to adapat to Christmas tree format. v4: change fixes tag format, and delay the actual call to tcp_full_space(). v3: add local variable full_space, add fixes tag. v2: fix for ipv6. net/ipv4/syncookies.c | 9 +++++++-- net/ipv6/syncookies.c | 10 ++++++++-- 2 files changed, 15 insertions(+), 4 deletions(-) diff --git a/net/ipv4/syncookies.c b/net/ipv4/syncookies.c index 6ac473b..00dc3f9 100644 --- a/net/ipv4/syncookies.c +++ b/net/ipv4/syncookies.c @@ -331,7 +331,7 @@ struct sock *cookie_v4_check(struct sock *sk, struct sk_buff *skb) __u32 cookie = ntohl(th->ack_seq) - 1; struct sock *ret = sk; struct request_sock *req; - int mss; + int full_space, mss; struct rtable *rt; __u8 rcv_wscale; struct flowi4 fl4; @@ -427,8 +427,13 @@ struct sock *cookie_v4_check(struct sock *sk, struct sk_buff *skb) /* Try to redo what tcp_v4_send_synack did. */ req->rsk_window_clamp = tp->window_clamp ? :dst_metric(&rt->dst, RTAX_WINDOW); + /* limit the window selection if the user enforce a smaller rx buffer */ + full_space = tcp_full_space(sk); + if (sk->sk_userlocks & SOCK_RCVBUF_LOCK && + (req->rsk_window_clamp > full_space || req->rsk_window_clamp = 0)) + req->rsk_window_clamp = full_space; - tcp_select_initial_window(sk, tcp_full_space(sk), req->mss, + tcp_select_initial_window(sk, full_space, req->mss, &req->rsk_rcv_wnd, &req->rsk_window_clamp, ireq->wscale_ok, &rcv_wscale, dst_metric(&rt->dst, RTAX_INITRWND)); diff --git a/net/ipv6/syncookies.c b/net/ipv6/syncookies.c index e796a64..9b6cae1 100644 --- a/net/ipv6/syncookies.c +++ b/net/ipv6/syncookies.c @@ -136,7 +136,7 @@ struct sock *cookie_v6_check(struct sock *sk, struct sk_buff *skb) __u32 cookie = ntohl(th->ack_seq) - 1; struct sock *ret = sk; struct request_sock *req; - int mss; + int full_space, mss; struct dst_entry *dst; __u8 rcv_wscale; u32 tsoff = 0; @@ -241,7 +241,13 @@ struct sock *cookie_v6_check(struct sock *sk, struct sk_buff *skb) } req->rsk_window_clamp = tp->window_clamp ? :dst_metric(dst, RTAX_WINDOW); - tcp_select_initial_window(sk, tcp_full_space(sk), req->mss, + /* limit the window selection if the user enforce a smaller rx buffer */ + full_space = tcp_full_space(sk); + if (sk->sk_userlocks & SOCK_RCVBUF_LOCK && + (req->rsk_window_clamp > full_space || req->rsk_window_clamp = 0)) + req->rsk_window_clamp = full_space; + + tcp_select_initial_window(sk, full_space, req->mss, &req->rsk_rcv_wnd, &req->rsk_window_clamp, ireq->wscale_ok, &rcv_wscale, dst_metric(dst, RTAX_INITRWND)); -- 1.8.3.1
next prev parent reply other threads:[~2020-11-10 0:16 UTC|newest] Thread overview: 32+ messages / expand[flat|nested] mbox.gz Atom feed top 2020-11-09 9:20 [PATCH] net: Update window_clamp if SOCK_RCVBUF is set Mao Wenan 2020-11-09 9:20 ` Mao Wenan 2020-11-09 9:33 ` [PATCH net v2] " Mao Wenan 2020-11-09 9:33 ` Mao Wenan 2020-11-09 9:56 ` Eric Dumazet 2020-11-09 9:56 ` Eric Dumazet 2020-11-09 10:12 ` Mao Wenan 2020-11-09 10:12 ` Mao Wenan 2020-11-09 10:19 ` Mao Wenan 2020-11-09 10:19 ` Mao Wenan 2020-11-09 11:02 ` Eric Dumazet 2020-11-09 11:02 ` Eric Dumazet 2020-11-09 11:41 ` Eric Dumazet 2020-11-09 11:41 ` Eric Dumazet 2020-11-09 14:01 ` Eric Dumazet 2020-11-09 14:01 ` Eric Dumazet 2020-11-09 16:26 ` Mao Wenan 2020-11-09 16:26 ` Mao Wenan 2020-11-09 16:53 ` [PATCH net v3] " Mao Wenan 2020-11-09 16:53 ` Mao Wenan 2020-11-09 16:59 ` Eric Dumazet 2020-11-09 16:59 ` Eric Dumazet 2020-11-09 17:17 ` [PATCH net v4] " Mao Wenan 2020-11-09 17:17 ` Mao Wenan 2020-11-09 17:28 ` Eric Dumazet 2020-11-09 17:28 ` Eric Dumazet 2020-11-10 0:16 ` Mao Wenan [this message] 2020-11-10 0:16 ` [PATCH net v5] " Mao Wenan 2020-11-10 7:32 ` Eric Dumazet 2020-11-10 7:32 ` Eric Dumazet 2020-11-11 1:45 ` Jakub Kicinski 2020-11-11 1:45 ` Jakub Kicinski
Reply instructions: You may reply publicly to this message via plain-text email using any one of the following methods: * Save the following mbox file, import it into your mail client, and reply-to-all from there: mbox Avoid top-posting and favor interleaved quoting: https://en.wikipedia.org/wiki/Posting_style#Interleaved_style * Reply using the --to, --cc, and --in-reply-to switches of git-send-email(1): git send-email \ --in-reply-to=1604967391-123737-1-git-send-email-wenan.mao@linux.alibaba.com \ --to=wenan.mao@linux.alibaba.com \ --cc=davem@davemloft.net \ --cc=edumazet@google.com \ --cc=kernel-janitors@vger.kernel.org \ --cc=kuba@kernel.org \ --cc=kuznet@ms2.inr.ac.ru \ --cc=linux-kernel@vger.kernel.org \ --cc=netdev@vger.kernel.org \ --cc=yoshfuji@linux-ipv6.org \ /path/to/YOUR_REPLY https://kernel.org/pub/software/scm/git/docs/git-send-email.html * If your mail client supports setting the In-Reply-To header via mailto: links, try the mailto: linkBe sure your reply has a Subject: header at the top and a blank line before the message body.
This is an external index of several public inboxes, see mirroring instructions on how to clone and mirror all data and code used by this external index.