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authorEric Dumazet <edumazet@google.com>2022-02-01 21:46:40 +0300
committerJakub Kicinski <kuba@kernel.org>2022-02-03 03:22:37 +0300
commitb67985be400969578d4d4b17299714c0e5d2c07b (patch)
tree68457fa31da2ea88566fab29049f5565aed425b7 /net
parent81eb8b0b18789e647e65579303529fd52d861cc2 (diff)
downloadlinux-b67985be400969578d4d4b17299714c0e5d2c07b.tar.xz
tcp: add missing tcp_skb_can_collapse() test in tcp_shift_skb_data()
tcp_shift_skb_data() might collapse three packets into a larger one. P_A, P_B, P_C -> P_ABC Historically, it used a single tcp_skb_can_collapse_to(P_A) call, because it was enough. In commit 85712484110d ("tcp: coalesce/collapse must respect MPTCP extensions"), this call was replaced by a call to tcp_skb_can_collapse(P_A, P_B) But the now needed test over P_C has been missed. This probably broke MPTCP. Then later, commit 9b65b17db723 ("net: avoid double accounting for pure zerocopy skbs") added an extra condition to tcp_skb_can_collapse(), but the missing call from tcp_shift_skb_data() is also breaking TCP zerocopy, because P_A and P_C might have different skb_zcopy_pure() status. Fixes: 85712484110d ("tcp: coalesce/collapse must respect MPTCP extensions") Fixes: 9b65b17db723 ("net: avoid double accounting for pure zerocopy skbs") Signed-off-by: Eric Dumazet <edumazet@google.com> Cc: Mat Martineau <mathew.j.martineau@linux.intel.com> Cc: Talal Ahmad <talalahmad@google.com> Cc: Arjun Roy <arjunroy@google.com> Cc: Willem de Bruijn <willemb@google.com> Acked-by: Soheil Hassas Yeganeh <soheil@google.com> Acked-by: Paolo Abeni <pabeni@redhat.com> Link: https://lore.kernel.org/r/20220201184640.756716-1-eric.dumazet@gmail.com Signed-off-by: Jakub Kicinski <kuba@kernel.org>
Diffstat (limited to 'net')
-rw-r--r--net/ipv4/tcp_input.c2
1 files changed, 2 insertions, 0 deletions
diff --git a/net/ipv4/tcp_input.c b/net/ipv4/tcp_input.c
index dc49a3d551eb..bfe4112e000c 100644
--- a/net/ipv4/tcp_input.c
+++ b/net/ipv4/tcp_input.c
@@ -1660,6 +1660,8 @@ static struct sk_buff *tcp_shift_skb_data(struct sock *sk, struct sk_buff *skb,
(mss != tcp_skb_seglen(skb)))
goto out;
+ if (!tcp_skb_can_collapse(prev, skb))
+ goto out;
len = skb->len;
pcount = tcp_skb_pcount(skb);
if (tcp_skb_shift(prev, skb, pcount, len))