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 3DDD2C433EF for ; Wed, 9 Mar 2022 16:34:59 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S229930AbiCIQfw (ORCPT ); Wed, 9 Mar 2022 11:35:52 -0500 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:47738 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S234335AbiCIQcq (ORCPT ); Wed, 9 Mar 2022 11:32:46 -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 3A4C81AAFF5; Wed, 9 Mar 2022 08:28:14 -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 95D8FB82206; Wed, 9 Mar 2022 16:28:00 +0000 (UTC) Received: by smtp.kernel.org (Postfix) with ESMTPSA id 16F9FC340EC; Wed, 9 Mar 2022 16:27:54 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1646843279; bh=Ma9ZQqofYHwDllZwZnYHjVafCmSXbxa84QLGIPjvGLs=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=btXt9O4YChi4CXfn/YzlVLXgwfRRit/bCdgODm2BopC4eqWfxuLGnk2zRdH69QN1v 1nIH0IrPwyghSrXx4DtFGeW4p7g/CB8xaf0cd8HqD3opz9B5oLLsai7uHzsbFaRRjq SdUo+0TOX1Q9um8hJYApBBeanwakIcnMQmI6/fD/XwYGxv+syF8nmvStlYrhfDAeMQ yM3LrCDB2+IANnNn8FFeu08lKf/ukgN+Outohmlhbx3XeyEb0M+c01s8IpULK8m8QW S8PmoQH2fqNme9ZZ28UQzjsF21zwFVAZztLcod0s68M1DY+VxBZAYbX0rYGtHPLAQq m/R5aL71mIqLg== From: Sasha Levin To: linux-kernel@vger.kernel.org, stable@vger.kernel.org Cc: Eric Dumazet , John Fastabend , Jakub Sitnicki , Daniel Borkmann , Jakub Kicinski , Sasha Levin , davem@davemloft.net, yoshfuji@linux-ipv6.org, dsahern@kernel.org, netdev@vger.kernel.org Subject: [PATCH AUTOSEL 4.9 08/11] tcp: make tcp_read_sock() more robust Date: Wed, 9 Mar 2022 11:27:13 -0500 Message-Id: <20220309162716.137399-8-sashal@kernel.org> X-Mailer: git-send-email 2.34.1 In-Reply-To: <20220309162716.137399-1-sashal@kernel.org> References: <20220309162716.137399-1-sashal@kernel.org> MIME-Version: 1.0 X-stable: review X-Patchwork-Hint: Ignore Content-Transfer-Encoding: 8bit Precedence: bulk List-ID: X-Mailing-List: netdev@vger.kernel.org From: Eric Dumazet [ Upstream commit e3d5ea2c011ecb16fb94c56a659364e6b30fac94 ] If recv_actor() returns an incorrect value, tcp_read_sock() might loop forever. Instead, issue a one time warning and make sure to make progress. Signed-off-by: Eric Dumazet Acked-by: John Fastabend Acked-by: Jakub Sitnicki Acked-by: Daniel Borkmann Link: https://lore.kernel.org/r/20220302161723.3910001-2-eric.dumazet@gmail.com Signed-off-by: Jakub Kicinski Signed-off-by: Sasha Levin --- net/ipv4/tcp.c | 10 ++++++---- 1 file changed, 6 insertions(+), 4 deletions(-) diff --git a/net/ipv4/tcp.c b/net/ipv4/tcp.c index aeda018e4c49..6dfb964e1ad8 100644 --- a/net/ipv4/tcp.c +++ b/net/ipv4/tcp.c @@ -1561,11 +1561,13 @@ int tcp_read_sock(struct sock *sk, read_descriptor_t *desc, if (!copied) copied = used; break; - } else if (used <= len) { - seq += used; - copied += used; - offset += used; } + if (WARN_ON_ONCE(used > len)) + used = len; + seq += used; + copied += used; + offset += used; + /* If recv_actor drops the lock (e.g. TCP splice * receive) the skb pointer might be invalid when * getting here: tcp_collapse might have deleted it -- 2.34.1