From patchwork Thu May 27 23:31:37 2021 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Mat Martineau X-Patchwork-Id: 12285661 X-Patchwork-Delegate: mat@martineau.name Received: from mga14.intel.com (mga14.intel.com [192.55.52.115]) (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 CF2826D00 for ; Thu, 27 May 2021 23:31:47 +0000 (UTC) IronPort-SDR: MXx5E4rQ5F1+V8k4PTCCNIN3fKfGXAV/Mt3+qumhE+Nhcue+SU/ZmqXo0/DWD363baes0U9XGT fyUMbSVeDU0A== X-IronPort-AV: E=McAfee;i="6200,9189,9997"; a="202623687" X-IronPort-AV: E=Sophos;i="5.83,228,1616482800"; d="scan'208";a="202623687" Received: from orsmga001.jf.intel.com ([10.7.209.18]) by fmsmga103.fm.intel.com with ESMTP/TLS/ECDHE-RSA-AES256-GCM-SHA384; 27 May 2021 16:31:45 -0700 IronPort-SDR: kH00Y9shY11yaf6vp9N3dNmq0fzho3qCBxEzQkqscO5w238UO3/42SQDRfqrzkmquSTFN1npzy q3Xnhq181D8A== X-IronPort-AV: E=Sophos;i="5.83,228,1616482800"; d="scan'208";a="477700331" Received: from mjmartin-desk2.amr.corp.intel.com (HELO mjmartin-desk2.intel.com) ([10.209.84.136]) by orsmga001-auth.jf.intel.com with ESMTP/TLS/ECDHE-RSA-AES256-GCM-SHA384; 27 May 2021 16:31:45 -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, Mat Martineau Subject: [PATCH net 1/4] mptcp: fix sk_forward_memory corruption on retransmission Date: Thu, 27 May 2021 16:31:37 -0700 Message-Id: <20210527233140.182728-2-mathew.j.martineau@linux.intel.com> X-Mailer: git-send-email 2.31.1 In-Reply-To: <20210527233140.182728-1-mathew.j.martineau@linux.intel.com> References: <20210527233140.182728-1-mathew.j.martineau@linux.intel.com> X-Mailing-List: mptcp@lists.linux.dev List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 From: Paolo Abeni MPTCP sk_forward_memory handling is a bit special, as such field is protected by the msk socket spin_lock, instead of the plain socket lock. Currently we have a code path updating such field without handling the relevant lock: __mptcp_retrans() -> __mptcp_clean_una_wakeup() Several helpers in __mptcp_clean_una_wakeup() will update sk_forward_alloc, possibly causing such field corruption, as reported by Matthieu. Address the issue providing and using a new variant of blamed function which explicitly acquires the msk spin lock. Fixes: 64b9cea7a0af ("mptcp: fix spurious retransmissions") Closes: https://github.com/multipath-tcp/mptcp_net-next/issues/172 Reported-by: Matthieu Baerts Tested-by: Matthieu Baerts Signed-off-by: Paolo Abeni Signed-off-by: Mat Martineau --- net/mptcp/protocol.c | 16 +++++++++++++++- 1 file changed, 15 insertions(+), 1 deletion(-) diff --git a/net/mptcp/protocol.c b/net/mptcp/protocol.c index 2bc199549a88..5edc686faff1 100644 --- a/net/mptcp/protocol.c +++ b/net/mptcp/protocol.c @@ -947,6 +947,10 @@ static void __mptcp_update_wmem(struct sock *sk) { struct mptcp_sock *msk = mptcp_sk(sk); +#ifdef CONFIG_LOCKDEP + WARN_ON_ONCE(!lockdep_is_held(&sk->sk_lock.slock)); +#endif + if (!msk->wmem_reserved) return; @@ -1085,10 +1089,20 @@ static void __mptcp_clean_una(struct sock *sk) static void __mptcp_clean_una_wakeup(struct sock *sk) { +#ifdef CONFIG_LOCKDEP + WARN_ON_ONCE(!lockdep_is_held(&sk->sk_lock.slock)); +#endif __mptcp_clean_una(sk); mptcp_write_space(sk); } +static void mptcp_clean_una_wakeup(struct sock *sk) +{ + mptcp_data_lock(sk); + __mptcp_clean_una_wakeup(sk); + mptcp_data_unlock(sk); +} + static void mptcp_enter_memory_pressure(struct sock *sk) { struct mptcp_subflow_context *subflow; @@ -2299,7 +2313,7 @@ static void __mptcp_retrans(struct sock *sk) struct sock *ssk; int ret; - __mptcp_clean_una_wakeup(sk); + mptcp_clean_una_wakeup(sk); dfrag = mptcp_rtx_head(sk); if (!dfrag) { if (mptcp_data_fin_enabled(msk)) {