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authorPaolo Abeni <pabeni@redhat.com>2023-12-04 17:08:05 +0100
committerJakub Kicinski <kuba@kernel.org>2023-12-06 05:07:02 +0100
commit58d3aade20cdddbac6c9707ac0f3f5f8c1278b74 (patch)
treecb236954a4b2b7a6db71e238163a273bfc3ae8fb /include/net/tcp.h
parentnet: bnxt: fix a potential use-after-free in bnxt_init_tc (diff)
downloadlinux-58d3aade20cdddbac6c9707ac0f3f5f8c1278b74.tar.xz
linux-58d3aade20cdddbac6c9707ac0f3f5f8c1278b74.zip
tcp: fix mid stream window clamp.
After the blamed commit below, if the user-space application performs window clamping when tp->rcv_wnd is 0, the TCP socket will never be able to announce a non 0 receive window, even after completely emptying the receive buffer and re-setting the window clamp to higher values. Refactor tcp_set_window_clamp() to address the issue: when the user decreases the current clamp value, set rcv_ssthresh according to the same logic used at buffer initialization, but ensuring reserved mem provisioning. To avoid code duplication factor-out the relevant bits from tcp_adjust_rcv_ssthresh() in a new helper and reuse it in the above scenario. When increasing the clamp value, give the rcv_ssthresh a chance to grow according to previously implemented heuristic. Fixes: 3aa7857fe1d7 ("tcp: enable mid stream window clamp") Reported-by: David Gibson <david@gibson.dropbear.id.au> Reported-by: Stefano Brivio <sbrivio@redhat.com> Signed-off-by: Paolo Abeni <pabeni@redhat.com> Reviewed-by: Eric Dumazet <edumazet@google.com> Link: https://lore.kernel.org/r/705dad54e6e6e9a010e571bf58e0b35a8ae70503.1701706073.git.pabeni@redhat.com Signed-off-by: Jakub Kicinski <kuba@kernel.org>
Diffstat (limited to 'include/net/tcp.h')
-rw-r--r--include/net/tcp.h9
1 files changed, 7 insertions, 2 deletions
diff --git a/include/net/tcp.h b/include/net/tcp.h
index d2f0736b76b8..144ba48bb07b 100644
--- a/include/net/tcp.h
+++ b/include/net/tcp.h
@@ -1514,17 +1514,22 @@ static inline int tcp_full_space(const struct sock *sk)
return tcp_win_from_space(sk, READ_ONCE(sk->sk_rcvbuf));
}
-static inline void tcp_adjust_rcv_ssthresh(struct sock *sk)
+static inline void __tcp_adjust_rcv_ssthresh(struct sock *sk, u32 new_ssthresh)
{
int unused_mem = sk_unused_reserved_mem(sk);
struct tcp_sock *tp = tcp_sk(sk);
- tp->rcv_ssthresh = min(tp->rcv_ssthresh, 4U * tp->advmss);
+ tp->rcv_ssthresh = min(tp->rcv_ssthresh, new_ssthresh);
if (unused_mem)
tp->rcv_ssthresh = max_t(u32, tp->rcv_ssthresh,
tcp_win_from_space(sk, unused_mem));
}
+static inline void tcp_adjust_rcv_ssthresh(struct sock *sk)
+{
+ __tcp_adjust_rcv_ssthresh(sk, 4U * tcp_sk(sk)->advmss);
+}
+
void tcp_cleanup_rbuf(struct sock *sk, int copied);
void __tcp_cleanup_rbuf(struct sock *sk, int copied);