From patchwork Thu Mar 17 12:45:51 2022 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Greg KH X-Patchwork-Id: 552571 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 23172C433EF for ; Thu, 17 Mar 2022 12:50:22 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S234011AbiCQMvf (ORCPT ); Thu, 17 Mar 2022 08:51:35 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:39348 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S234053AbiCQMvC (ORCPT ); Thu, 17 Mar 2022 08:51:02 -0400 Received: from dfw.source.kernel.org (dfw.source.kernel.org [IPv6:2604:1380:4641:c500::1]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id A03AC1F6343; Thu, 17 Mar 2022 05:49:09 -0700 (PDT) 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 dfw.source.kernel.org (Postfix) with ESMTPS id 3809461463; Thu, 17 Mar 2022 12:49:09 +0000 (UTC) Received: by smtp.kernel.org (Postfix) with ESMTPSA id 19928C340ED; Thu, 17 Mar 2022 12:49:07 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=linuxfoundation.org; s=korg; t=1647521348; bh=Us0ddea7M4LNimZ1TRqKszvcE3LyqV9O8BoBA/Mrw4M=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=1w1ht0uTJNmJmtCLZ6yM2ZeCzWi49BDfU1GhBZWBwC1rjv64k7b4RMjw8S94mRCps /j6x5/HPmrjkkYD8fVL6ydvz3KPtAH7fL2Ldk1eMKUGA2GaNa63KRcq3/26boTJ8Xx 9rJ4xp0sRyQl4iSwmdZdraSDQPWgooptN5wFJsvU= From: Greg Kroah-Hartman To: linux-kernel@vger.kernel.org Cc: Greg Kroah-Hartman , stable@vger.kernel.org, Eric Dumazet , John Fastabend , Jakub Sitnicki , Daniel Borkmann , Jakub Kicinski , Sasha Levin Subject: [PATCH 5.4 40/43] tcp: make tcp_read_sock() more robust Date: Thu, 17 Mar 2022 13:45:51 +0100 Message-Id: <20220317124528.782652194@linuxfoundation.org> X-Mailer: git-send-email 2.35.1 In-Reply-To: <20220317124527.672236844@linuxfoundation.org> References: <20220317124527.672236844@linuxfoundation.org> User-Agent: quilt/0.66 MIME-Version: 1.0 Precedence: bulk List-ID: X-Mailing-List: stable@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 9f53d25e047e..4815cf72569e 100644 --- a/net/ipv4/tcp.c +++ b/net/ipv4/tcp.c @@ -1652,11 +1652,13 @@ 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