From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from smtp.kernel.org (aws-us-west-2-korg-mail-1.web.codeaurora.org [10.30.226.201]) (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 9C7B51ED38 for ; Tue, 25 Jul 2023 11:34:48 +0000 (UTC) Received: by smtp.kernel.org (Postfix) with ESMTPSA id 1D912C433C7; Tue, 25 Jul 2023 11:34:47 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=linuxfoundation.org; s=korg; t=1690284888; bh=DON+5ehH52udqMugYgLDqjV5lnXU0mqdmyHNzUV7NGU=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=faiaf/amydn8XzFesarz01rrZMx8HmiSGRLJa9KQqBfbuhvMb/7UYIlS9YDawUY6N kJXX1JqSLUSSUrqIO7Rdk4miiNJus6kB9KQ2jyatjSR0fJjdC1HGJPK4js8gkfqD0C ucdjcBfgBKlFwcBiiyUJOFAzbeIdC4r19IZw9F54= From: Greg Kroah-Hartman To: stable@vger.kernel.org Cc: Greg Kroah-Hartman , patches@lists.linux.dev, Kuniyuki Iwashima , "David S. Miller" , Sasha Levin Subject: [PATCH 5.10 498/509] tcp: Fix data-races around sysctl_tcp_syn(ack)?_retries. Date: Tue, 25 Jul 2023 12:47:17 +0200 Message-ID: <20230725104616.547004126@linuxfoundation.org> X-Mailer: git-send-email 2.41.0 In-Reply-To: <20230725104553.588743331@linuxfoundation.org> References: <20230725104553.588743331@linuxfoundation.org> User-Agent: quilt/0.67 Precedence: bulk X-Mailing-List: patches@lists.linux.dev List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit From: Kuniyuki Iwashima [ Upstream commit 20a3b1c0f603e8c55c3396abd12dfcfb523e4d3c ] While reading sysctl_tcp_syn(ack)?_retries, they can be changed concurrently. Thus, we need to add READ_ONCE() to their readers. Fixes: 1da177e4c3f4 ("Linux-2.6.12-rc2") Signed-off-by: Kuniyuki Iwashima Signed-off-by: David S. Miller Stable-dep-of: 3a037f0f3c4b ("tcp: annotate data-races around icsk->icsk_syn_retries") Signed-off-by: Sasha Levin --- net/ipv4/inet_connection_sock.c | 3 ++- net/ipv4/tcp.c | 3 ++- net/ipv4/tcp_timer.c | 10 +++++++--- 3 files changed, 11 insertions(+), 5 deletions(-) diff --git a/net/ipv4/inet_connection_sock.c b/net/ipv4/inet_connection_sock.c index 406305aaec904..dfea3088bc7e9 100644 --- a/net/ipv4/inet_connection_sock.c +++ b/net/ipv4/inet_connection_sock.c @@ -740,7 +740,8 @@ static void reqsk_timer_handler(struct timer_list *t) if (inet_sk_state_load(sk_listener) != TCP_LISTEN) goto drop; - max_syn_ack_retries = icsk->icsk_syn_retries ? : net->ipv4.sysctl_tcp_synack_retries; + max_syn_ack_retries = icsk->icsk_syn_retries ? : + READ_ONCE(net->ipv4.sysctl_tcp_synack_retries); /* Normally all the openreqs are young and become mature * (i.e. converted to established socket) for first timeout. * If synack was not acknowledged for 1 second, it means diff --git a/net/ipv4/tcp.c b/net/ipv4/tcp.c index 80212bb0400c2..fc4d560909b50 100644 --- a/net/ipv4/tcp.c +++ b/net/ipv4/tcp.c @@ -3743,7 +3743,8 @@ static int do_tcp_getsockopt(struct sock *sk, int level, val = keepalive_probes(tp); break; case TCP_SYNCNT: - val = icsk->icsk_syn_retries ? : net->ipv4.sysctl_tcp_syn_retries; + val = icsk->icsk_syn_retries ? : + READ_ONCE(net->ipv4.sysctl_tcp_syn_retries); break; case TCP_LINGER2: val = tp->linger2; diff --git a/net/ipv4/tcp_timer.c b/net/ipv4/tcp_timer.c index 888683f2ff3ee..715fdfa3e2ae9 100644 --- a/net/ipv4/tcp_timer.c +++ b/net/ipv4/tcp_timer.c @@ -239,7 +239,8 @@ static int tcp_write_timeout(struct sock *sk) if ((1 << sk->sk_state) & (TCPF_SYN_SENT | TCPF_SYN_RECV)) { if (icsk->icsk_retransmits) __dst_negative_advice(sk); - retry_until = icsk->icsk_syn_retries ? : net->ipv4.sysctl_tcp_syn_retries; + retry_until = icsk->icsk_syn_retries ? : + READ_ONCE(net->ipv4.sysctl_tcp_syn_retries); expired = icsk->icsk_retransmits >= retry_until; } else { if (retransmits_timed_out(sk, READ_ONCE(net->ipv4.sysctl_tcp_retries1), 0)) { @@ -406,12 +407,15 @@ abort: tcp_write_err(sk); static void tcp_fastopen_synack_timer(struct sock *sk, struct request_sock *req) { struct inet_connection_sock *icsk = inet_csk(sk); - int max_retries = icsk->icsk_syn_retries ? : - sock_net(sk)->ipv4.sysctl_tcp_synack_retries + 1; /* add one more retry for fastopen */ struct tcp_sock *tp = tcp_sk(sk); + int max_retries; req->rsk_ops->syn_ack_timeout(req); + /* add one more retry for fastopen */ + max_retries = icsk->icsk_syn_retries ? : + READ_ONCE(sock_net(sk)->ipv4.sysctl_tcp_synack_retries) + 1; + if (req->num_timeout >= max_retries) { tcp_write_err(sk); return; -- 2.39.2