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net: Update window_clamp if SOCK_RCVBUF is set
[ Upstream commit909172a149
] 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:e88c64f0a4
("tcp: allow effective reduction of TCP's rcv-buffer via setsockopt") Signed-off-by: Mao Wenan <wenan.mao@linux.alibaba.com> Signed-off-by: Eric Dumazet <edumazet@google.com> Link: https://lore.kernel.org/r/1604967391-123737-1-git-send-email-wenan.mao@linux.alibaba.com Signed-off-by: Jakub Kicinski <kuba@kernel.org> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
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parent
6c7cd7a91b
commit
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2 changed files with 15 additions and 4 deletions
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@ -296,7 +296,7 @@ struct sock *cookie_v4_check(struct sock *sk, struct sk_buff *skb)
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__u32 cookie = ntohl(th->ack_seq) - 1;
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struct sock *ret = sk;
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struct request_sock *req;
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int mss;
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int full_space, mss;
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struct rtable *rt;
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__u8 rcv_wscale;
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struct flowi4 fl4;
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@ -389,8 +389,13 @@ struct sock *cookie_v4_check(struct sock *sk, struct sk_buff *skb)
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/* Try to redo what tcp_v4_send_synack did. */
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req->rsk_window_clamp = tp->window_clamp ? :dst_metric(&rt->dst, RTAX_WINDOW);
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/* limit the window selection if the user enforce a smaller rx buffer */
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full_space = tcp_full_space(sk);
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if (sk->sk_userlocks & SOCK_RCVBUF_LOCK &&
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(req->rsk_window_clamp > full_space || req->rsk_window_clamp == 0))
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req->rsk_window_clamp = full_space;
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tcp_select_initial_window(tcp_full_space(sk), req->mss,
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tcp_select_initial_window(full_space, req->mss,
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&req->rsk_rcv_wnd, &req->rsk_window_clamp,
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ireq->wscale_ok, &rcv_wscale,
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dst_metric(&rt->dst, RTAX_INITRWND));
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@ -141,7 +141,7 @@ struct sock *cookie_v6_check(struct sock *sk, struct sk_buff *skb)
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__u32 cookie = ntohl(th->ack_seq) - 1;
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struct sock *ret = sk;
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struct request_sock *req;
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int mss;
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int full_space, mss;
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struct dst_entry *dst;
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__u8 rcv_wscale;
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u32 tsoff = 0;
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@ -244,7 +244,13 @@ struct sock *cookie_v6_check(struct sock *sk, struct sk_buff *skb)
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}
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req->rsk_window_clamp = tp->window_clamp ? :dst_metric(dst, RTAX_WINDOW);
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tcp_select_initial_window(tcp_full_space(sk), req->mss,
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/* limit the window selection if the user enforce a smaller rx buffer */
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full_space = tcp_full_space(sk);
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if (sk->sk_userlocks & SOCK_RCVBUF_LOCK &&
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(req->rsk_window_clamp > full_space || req->rsk_window_clamp == 0))
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req->rsk_window_clamp = full_space;
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tcp_select_initial_window(full_space, req->mss,
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&req->rsk_rcv_wnd, &req->rsk_window_clamp,
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ireq->wscale_ok, &rcv_wscale,
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dst_metric(dst, RTAX_INITRWND));
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