From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from mga17.intel.com (mga17.intel.com [192.55.52.151]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id 4D47E2FB0 for ; Fri, 18 Jun 2021 22:02:30 +0000 (UTC) IronPort-SDR: i+K3aBPL7ZzqlZyUnvQxh67v5obWKOZRfWU+HcQnoY0j4NJG5IfSrKIUszT0D9J7xuDxvUfV3G kNwkuQZB7qGw== X-IronPort-AV: E=McAfee;i="6200,9189,10019"; a="187004135" X-IronPort-AV: E=Sophos;i="5.83,284,1616482800"; d="scan'208";a="187004135" Received: from orsmga007.jf.intel.com ([10.7.209.58]) by fmsmga107.fm.intel.com with ESMTP/TLS/ECDHE-RSA-AES256-GCM-SHA384; 18 Jun 2021 15:02:27 -0700 IronPort-SDR: E7BgKZAdnyEmq+vwF0de9WcEquueXC4EPviy63J01W9mT+p/xKCguUPFTcjU5LbTmomMXMPI3Y F3Wq2Cq3FE1g== X-IronPort-AV: E=Sophos;i="5.83,284,1616482800"; d="scan'208";a="443703682" Received: from mjmartin-desk2.amr.corp.intel.com (HELO mjmartin-desk2.intel.com) ([10.209.26.218]) by orsmga007-auth.jf.intel.com with ESMTP/TLS/ECDHE-RSA-AES256-GCM-SHA384; 18 Jun 2021 15:02:27 -0700 From: Mat Martineau To: netdev@vger.kernel.org Cc: Paolo Abeni , davem@davemloft.net, kuba@kernel.org, matthieu.baerts@tessares.net, mptcp@lists.linux.dev, fw@strlen.de, Mat Martineau Subject: [PATCH net 1/2] mptcp: fix bad handling of 32 bit ack wrap-around Date: Fri, 18 Jun 2021 15:02:20 -0700 Message-Id: <20210618220221.99172-2-mathew.j.martineau@linux.intel.com> X-Mailer: git-send-email 2.32.0 In-Reply-To: <20210618220221.99172-1-mathew.j.martineau@linux.intel.com> References: <20210618220221.99172-1-mathew.j.martineau@linux.intel.com> X-Mailing-List: mptcp@lists.linux.dev List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Transfer-Encoding: 8bit From: Paolo Abeni When receiving 32 bits DSS ack from the peer, the MPTCP need to expand them to 64 bits value. The current code is buggy WRT detecting 32 bits ack wrap-around: when the wrap-around happens the current unsigned 32 bit ack value is lower than the previous one. Additionally check for possible reverse wrap and make the helper visible, so that we could re-use it for the next patch. Closes: https://github.com/multipath-tcp/mptcp_net-next/issues/204 Fixes: cc9d25669866 ("mptcp: update per unacked sequence on pkt reception") Reviewed-by: Mat Martineau Signed-off-by: Paolo Abeni --- net/mptcp/options.c | 29 +++++++++++++++-------------- net/mptcp/protocol.h | 8 ++++++++ 2 files changed, 23 insertions(+), 14 deletions(-) diff --git a/net/mptcp/options.c b/net/mptcp/options.c index 9b263f27ce9b..b87e46f515fb 100644 --- a/net/mptcp/options.c +++ b/net/mptcp/options.c @@ -896,19 +896,20 @@ static bool check_fully_established(struct mptcp_sock *msk, struct sock *ssk, return false; } -static u64 expand_ack(u64 old_ack, u64 cur_ack, bool use_64bit) +u64 __mptcp_expand_seq(u64 old_seq, u64 cur_seq) { - u32 old_ack32, cur_ack32; - - if (use_64bit) - return cur_ack; - - old_ack32 = (u32)old_ack; - cur_ack32 = (u32)cur_ack; - cur_ack = (old_ack & GENMASK_ULL(63, 32)) + cur_ack32; - if (unlikely(before(cur_ack32, old_ack32))) - return cur_ack + (1LL << 32); - return cur_ack; + u32 old_seq32, cur_seq32; + + old_seq32 = (u32)old_seq; + cur_seq32 = (u32)cur_seq; + cur_seq = (old_seq & GENMASK_ULL(63, 32)) + cur_seq32; + if (unlikely(cur_seq32 < old_seq32 && before(old_seq32, cur_seq32))) + return cur_seq + (1LL << 32); + + /* reverse wrap could happen, too */ + if (unlikely(cur_seq32 > old_seq32 && after(old_seq32, cur_seq32))) + return cur_seq - (1LL << 32); + return cur_seq; } static void ack_update_msk(struct mptcp_sock *msk, @@ -926,7 +927,7 @@ static void ack_update_msk(struct mptcp_sock *msk, * more dangerous than missing an ack */ old_snd_una = msk->snd_una; - new_snd_una = expand_ack(old_snd_una, mp_opt->data_ack, mp_opt->ack64); + new_snd_una = mptcp_expand_seq(old_snd_una, mp_opt->data_ack, mp_opt->ack64); /* ACK for data not even sent yet? Ignore. */ if (after64(new_snd_una, snd_nxt)) @@ -963,7 +964,7 @@ bool mptcp_update_rcv_data_fin(struct mptcp_sock *msk, u64 data_fin_seq, bool us return false; WRITE_ONCE(msk->rcv_data_fin_seq, - expand_ack(READ_ONCE(msk->ack_seq), data_fin_seq, use_64bit)); + mptcp_expand_seq(READ_ONCE(msk->ack_seq), data_fin_seq, use_64bit)); WRITE_ONCE(msk->rcv_data_fin, 1); return true; diff --git a/net/mptcp/protocol.h b/net/mptcp/protocol.h index 385796f0ef19..5d7c44028e47 100644 --- a/net/mptcp/protocol.h +++ b/net/mptcp/protocol.h @@ -593,6 +593,14 @@ int mptcp_setsockopt(struct sock *sk, int level, int optname, int mptcp_getsockopt(struct sock *sk, int level, int optname, char __user *optval, int __user *option); +u64 __mptcp_expand_seq(u64 old_seq, u64 cur_seq); +static inline u64 mptcp_expand_seq(u64 old_seq, u64 cur_seq, bool use_64bit) +{ + if (use_64bit) + return cur_seq; + + return __mptcp_expand_seq(old_seq, cur_seq); +} void __mptcp_check_push(struct sock *sk, struct sock *ssk); void __mptcp_data_acked(struct sock *sk); void __mptcp_error_report(struct sock *sk); -- 2.32.0