From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by smtp.lore.kernel.org (Postfix) with ESMTP id E6078C64EC7 for ; Wed, 1 Mar 2023 00:29:04 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S229565AbjCAA3D (ORCPT ); Tue, 28 Feb 2023 19:29:03 -0500 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:34982 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S229523AbjCAA3D (ORCPT ); Tue, 28 Feb 2023 19:29:03 -0500 Received: from ams.source.kernel.org (ams.source.kernel.org [IPv6:2604:1380:4601:e00::1]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 5F7262103; Tue, 28 Feb 2023 16:29:02 -0800 (PST) Received: from smtp.kernel.org (relay.kernel.org [52.25.139.140]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by ams.source.kernel.org (Postfix) with ESMTPS id 154D4B80ED4; Wed, 1 Mar 2023 00:29:01 +0000 (UTC) Received: by smtp.kernel.org (Postfix) with ESMTPSA id 3A848C433D2; Wed, 1 Mar 2023 00:28:59 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1677630539; bh=/LI5yRBD+xU8o3fJ25yJ7tAxnhNvYlM9rrYR42TLgAY=; h=From:To:Cc:Subject:Date:From; b=Rv1UyHDZGT20ZCmWiR/oXR+Y3M0WRAURtFwscHQrTvES+JBLmG/CZcThlamAQOjs1 7eTlhRfW/9X2XF3vHKQ2IQrOM3qAdc2kqYPQfyXoWKWbY5CGN7xUbhl4PynUsPzLbt lq2u6Bx6+zaxOym6kFfBfs4DNuu8YPS+q7kdDEKjF24KME03+M8q1nIn2ubll6xipy 9esX2FLXpZHBBzAISP6DgkAYglMM59VPHaXQ3qamLVOBrk5NORqRkistthLCHyR7pT PFdidkFmP6M8FaQl8W8xZGRN9krq8/Wi0PG45TOxhP+/4kVG0SR1tCX7xKa2wZDOnI IVRQ4h3tbepdA== From: Jakub Kicinski To: davem@davemloft.net Cc: netdev@vger.kernel.org, edumazet@google.com, pabeni@redhat.com, Jakub Kicinski , syzbot+9c0268252b8ef967c62e@syzkaller.appspotmail.com, stable@vger.kernel.org, borisp@nvidia.com, john.fastabend@gmail.com, simon.horman@netronome.com Subject: [PATCH net] net: tls: avoid hanging tasks on the tx_lock Date: Tue, 28 Feb 2023 16:28:57 -0800 Message-Id: <20230301002857.2101894-1-kuba@kernel.org> X-Mailer: git-send-email 2.39.2 MIME-Version: 1.0 Content-Transfer-Encoding: 8bit Precedence: bulk List-ID: X-Mailing-List: stable@vger.kernel.org syzbot sent a hung task report and Eric explains that adversarial receiver may keep RWIN at 0 for a long time, so we are not guaranteed to make forward progress. Thread which took tx_lock and went to sleep may not release tx_lock for hours. Use interruptible sleep where possible and reschedule the work if it can't take the lock. Testing: existing selftest passes Reported-by: syzbot+9c0268252b8ef967c62e@syzkaller.appspotmail.com Fixes: 79ffe6087e91 ("net/tls: add a TX lock") Link: https://lore.kernel.org/all/000000000000e412e905f5b46201@google.com/ Cc: stable@vger.kernel.org # wait 4 weeks Signed-off-by: Jakub Kicinski --- CC: borisp@nvidia.com CC: john.fastabend@gmail.com CC: simon.horman@netronome.com --- net/tls/tls_sw.c | 26 +++++++++++++++++++------- 1 file changed, 19 insertions(+), 7 deletions(-) diff --git a/net/tls/tls_sw.c b/net/tls/tls_sw.c index 021d760f9133..635b8bf6b937 100644 --- a/net/tls/tls_sw.c +++ b/net/tls/tls_sw.c @@ -956,7 +956,9 @@ int tls_sw_sendmsg(struct sock *sk, struct msghdr *msg, size_t size) MSG_CMSG_COMPAT)) return -EOPNOTSUPP; - mutex_lock(&tls_ctx->tx_lock); + ret = mutex_lock_interruptible(&tls_ctx->tx_lock); + if (ret) + return ret; lock_sock(sk); if (unlikely(msg->msg_controllen)) { @@ -1290,7 +1292,9 @@ int tls_sw_sendpage(struct sock *sk, struct page *page, MSG_SENDPAGE_NOTLAST | MSG_SENDPAGE_NOPOLICY)) return -EOPNOTSUPP; - mutex_lock(&tls_ctx->tx_lock); + ret = mutex_lock_interruptible(&tls_ctx->tx_lock); + if (ret) + return ret; lock_sock(sk); ret = tls_sw_do_sendpage(sk, page, offset, size, flags); release_sock(sk); @@ -2435,11 +2439,19 @@ static void tx_work_handler(struct work_struct *work) if (!test_and_clear_bit(BIT_TX_SCHEDULED, &ctx->tx_bitmask)) return; - mutex_lock(&tls_ctx->tx_lock); - lock_sock(sk); - tls_tx_records(sk, -1); - release_sock(sk); - mutex_unlock(&tls_ctx->tx_lock); + + if (mutex_trylock(&tls_ctx->tx_lock)) { + lock_sock(sk); + tls_tx_records(sk, -1); + release_sock(sk); + mutex_unlock(&tls_ctx->tx_lock); + } else if (!test_and_set_bit(BIT_TX_SCHEDULED, &ctx->tx_bitmask)) { + /* Someone is holding the tx_lock, they will likely run Tx + * and cancel the work on their way out of the lock section. + * Schedule a long delay just in case. + */ + schedule_delayed_work(&ctx->tx_work.work, msecs_to_jiffies(10)); + } } static bool tls_is_tx_ready(struct tls_sw_context_tx *ctx) -- 2.39.2