From nobody Mon Sep 16 20:18:13 2024 Delivered-To: importer2@patchew.org Authentication-Results: mx.zohomail.com; spf=pass (zohomail.com: domain of gnu.org designates 209.51.188.17 as permitted sender) smtp.mailfrom=qemu-devel-bounces+importer2=patchew.org@nongnu.org Return-Path: Received: from lists.gnu.org (lists.gnu.org [209.51.188.17]) by mx.zohomail.com with SMTPS id 1712734734166945.083896477786; Wed, 10 Apr 2024 00:38:54 -0700 (PDT) Received: from localhost ([::1] helo=lists1p.gnu.org) by lists.gnu.org with esmtp (Exim 4.90_1) (envelope-from ) id 1ruSMK-00014t-Go; Wed, 10 Apr 2024 03:27:06 -0400 Received: from eggs.gnu.org ([2001:470:142:3::10]) by lists.gnu.org with esmtps (TLS1.2:ECDHE_RSA_AES_256_GCM_SHA384:256) (Exim 4.90_1) (envelope-from ) id 1ruSLy-0008Bb-8i; Wed, 10 Apr 2024 03:26:42 -0400 Received: from isrv.corpit.ru ([86.62.121.231]) by eggs.gnu.org with esmtps (TLS1.2:ECDHE_RSA_AES_256_GCM_SHA384:256) (Exim 4.90_1) (envelope-from ) id 1ruSLt-0004bU-LX; Wed, 10 Apr 2024 03:26:39 -0400 Received: from tsrv.corpit.ru (tsrv.tls.msk.ru [192.168.177.2]) by isrv.corpit.ru (Postfix) with ESMTP id 2BAFB5D696; Wed, 10 Apr 2024 10:25:05 +0300 (MSK) Received: from tls.msk.ru (mjt.wg.tls.msk.ru [192.168.177.130]) by tsrv.corpit.ru (Postfix) with SMTP id C4E89B02D6; Wed, 10 Apr 2024 10:23:06 +0300 (MSK) Received: (nullmailer pid 4191761 invoked by uid 1000); Wed, 10 Apr 2024 07:23:04 -0000 From: Michael Tokarev To: qemu-devel@nongnu.org Cc: qemu-stable@nongnu.org, =?UTF-8?q?Daniel=20P=2E=20Berrang=C3=A9?= , Thomas Huth , Michael Tokarev Subject: [Stable-8.2.3 38/87] Revert "chardev/char-socket: Fix TLS io channels sending too much data to the backend" Date: Wed, 10 Apr 2024 10:22:11 +0300 Message-Id: <20240410072303.4191455-38-mjt@tls.msk.ru> X-Mailer: git-send-email 2.39.2 In-Reply-To: References: MIME-Version: 1.0 Content-Type: text/plain; charset="utf-8" Content-Transfer-Encoding: quoted-printable Received-SPF: pass (zohomail.com: domain of gnu.org designates 209.51.188.17 as permitted sender) client-ip=209.51.188.17; envelope-from=qemu-devel-bounces+importer2=patchew.org@nongnu.org; helo=lists.gnu.org; Received-SPF: pass client-ip=86.62.121.231; envelope-from=mjt@tls.msk.ru; helo=isrv.corpit.ru X-Spam_score_int: -68 X-Spam_score: -6.9 X-Spam_bar: ------ X-Spam_report: (-6.9 / 5.0 requ) BAYES_00=-1.9, RCVD_IN_DNSWL_HI=-5, SPF_HELO_NONE=0.001, SPF_PASS=-0.001 autolearn=ham autolearn_force=no X-Spam_action: no action X-BeenThere: qemu-devel@nongnu.org X-Mailman-Version: 2.1.29 Precedence: list List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Errors-To: qemu-devel-bounces+importer2=patchew.org@nongnu.org Sender: qemu-devel-bounces+importer2=patchew.org@nongnu.org X-ZM-MESSAGEID: 1712734735523100007 From: Daniel P. Berrang=C3=A9 This commit results in unexpected termination of the TLS connection. When 'fd_can_read' returns 0, the code goes on to pass a zero length buffer to qio_channel_read. The TLS impl calls into gnutls_recv() with this zero length buffer, at which point GNUTLS returns an error GNUTLS_E_INVALID_REQUEST. This is treated as fatal by QEMU's TLS code resulting in the connection being torn down by the chardev. Simply skipping the qio_channel_read when the buffer length is zero is also not satisfactory, as it results in a high CPU burn busy loop massively slowing QEMU's functionality. The proper solution is to avoid tcp_chr_read being called at all unless the frontend is able to accept more data. This will be done in a followup commit. This reverts commit 462945cd22d2bcd233401ed3aa167d83a8e35b05 Reviewed-by: Thomas Huth Signed-off-by: Daniel P. Berrang=C3=A9 (cherry picked from commit e8ee827ffdb86ebbd5f5213a1f78123c25a90864) Signed-off-by: Michael Tokarev diff --git a/chardev/char-socket.c b/chardev/char-socket.c index 034840593d..73947da188 100644 --- a/chardev/char-socket.c +++ b/chardev/char-socket.c @@ -492,9 +492,9 @@ static gboolean tcp_chr_read(QIOChannel *chan, GIOCondi= tion cond, void *opaque) s->max_size <=3D 0) { return TRUE; } - len =3D tcp_chr_read_poll(opaque); - if (len > sizeof(buf)) { - len =3D sizeof(buf); + len =3D sizeof(buf); + if (len > s->max_size) { + len =3D s->max_size; } size =3D tcp_chr_recv(chr, (void *)buf, len); if (size =3D=3D 0 || (size =3D=3D -1 && errno !=3D EAGAIN)) { --=20 2.39.2