From nobody Sun May 5 23:45:47 2024 Delivered-To: importer@patchew.org Received-SPF: pass (zoho.com: domain of gnu.org designates 208.118.235.17 as permitted sender) client-ip=208.118.235.17; envelope-from=qemu-devel-bounces+importer=patchew.org@nongnu.org; helo=lists.gnu.org; Authentication-Results: mx.zohomail.com; spf=pass (zoho.com: domain of gnu.org designates 208.118.235.17 as permitted sender) smtp.mailfrom=qemu-devel-bounces+importer=patchew.org@nongnu.org; dmarc=fail(p=none dis=none) header.from=redhat.com Return-Path: Received: from lists.gnu.org (208.118.235.17 [208.118.235.17]) by mx.zohomail.com with SMTPS id 1542635025791211.87745649704004; Mon, 19 Nov 2018 05:43:45 -0800 (PST) Received: from localhost ([::1]:56219 helo=lists.gnu.org) by lists.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1gOjpu-0004e4-GE for importer@patchew.org; Mon, 19 Nov 2018 08:43:34 -0500 Received: from eggs.gnu.org ([2001:4830:134:3::10]:56894) by lists.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1gOjp5-0004G2-Td for qemu-devel@nongnu.org; Mon, 19 Nov 2018 08:42:44 -0500 Received: from Debian-exim by eggs.gnu.org with spam-scanned (Exim 4.71) (envelope-from ) id 1gOjoz-0002Ie-44 for qemu-devel@nongnu.org; Mon, 19 Nov 2018 08:42:43 -0500 Received: from mx1.redhat.com ([209.132.183.28]:59476) by eggs.gnu.org with esmtps (TLS1.0:DHE_RSA_AES_256_CBC_SHA1:32) (Exim 4.71) (envelope-from ) id 1gOjoy-0002Hu-TB for qemu-devel@nongnu.org; Mon, 19 Nov 2018 08:42:37 -0500 Received: from smtp.corp.redhat.com (int-mx02.intmail.prod.int.phx2.redhat.com [10.5.11.12]) (using TLSv1.2 with cipher AECDH-AES256-SHA (256/256 bits)) (No client certificate requested) by mx1.redhat.com (Postfix) with ESMTPS id 3077D30917A1 for ; Mon, 19 Nov 2018 13:42:36 +0000 (UTC) Received: from localhost.localdomain.com (unknown [10.42.22.189]) by smtp.corp.redhat.com (Postfix) with ESMTP id 5867D60BE7; Mon, 19 Nov 2018 13:42:35 +0000 (UTC) From: =?UTF-8?q?Daniel=20P=2E=20Berrang=C3=A9?= To: qemu-devel@nongnu.org Date: Mon, 19 Nov 2018 13:42:28 +0000 Message-Id: <20181119134228.11031-1-berrange@redhat.com> MIME-Version: 1.0 X-Scanned-By: MIMEDefang 2.79 on 10.5.11.12 X-Greylist: Sender IP whitelisted, not delayed by milter-greylist-4.5.16 (mx1.redhat.com [10.5.110.41]); Mon, 19 Nov 2018 13:42:36 +0000 (UTC) Content-Transfer-Encoding: quoted-printable X-detected-operating-system: by eggs.gnu.org: GNU/Linux 2.2.x-3.x [generic] X-Received-From: 209.132.183.28 Subject: [Qemu-devel] [PATCH] io: return 0 for EOF in TLS session read after shutdown X-BeenThere: qemu-devel@nongnu.org X-Mailman-Version: 2.1.21 Precedence: list List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Errors-To: qemu-devel-bounces+importer=patchew.org@nongnu.org Sender: "Qemu-devel" Content-Type: text/plain; charset="utf-8" GNUTLS takes a paranoid approach when seeing 0 bytes returned by the underlying OS read() function. It will consider this an error and return GNUTLS_E_PREMATURE_TERMINATION instead of propagating the 0 return value. It expects apps to arrange for clean termination at the protocol level and not rely on seeing EOF from a read call to detect shutdown. This is to harden apps against a malicious 3rd party causing termination of the sockets layer. This is unhelpful for the QEMU NBD code which does have a clean protocol level shutdown, but still relies on seeing 0 from the I/O channel read in the coroutine handling incoming replies. The upshot is that when using a plain NBD connection shutdown is silent, but when using TLS, the client spams the console with Cannot read from TLS channel: Broken pipe The NBD connection has, however, called qio_channel_shutdown() at this point to indicate that it is done with I/O. This gives the opportunity to optimize the code such that when the channel has been shutdown in the read direction, the error code GNUTLS_E_PREMATURE_TERMINATION gets turned into a '0' return instead of an error. Signed-off-by: Daniel P. Berrang=C3=A9 Reviewed-by: Eric Blake --- crypto/tlssession.c | 3 +++ include/io/channel-tls.h | 1 + include/io/channel.h | 6 +++--- io/channel-tls.c | 5 +++++ 4 files changed, 12 insertions(+), 3 deletions(-) diff --git a/crypto/tlssession.c b/crypto/tlssession.c index 2f28fa7f71..0dedd4af52 100644 --- a/crypto/tlssession.c +++ b/crypto/tlssession.c @@ -473,6 +473,9 @@ qcrypto_tls_session_read(QCryptoTLSSession *session, case GNUTLS_E_INTERRUPTED: errno =3D EINTR; break; + case GNUTLS_E_PREMATURE_TERMINATION: + errno =3D ECONNABORTED; + break; default: errno =3D EIO; break; diff --git a/include/io/channel-tls.h b/include/io/channel-tls.h index 87fcaf9146..fdbdf12feb 100644 --- a/include/io/channel-tls.h +++ b/include/io/channel-tls.h @@ -48,6 +48,7 @@ struct QIOChannelTLS { QIOChannel parent; QIOChannel *master; QCryptoTLSSession *session; + QIOChannelShutdown shutdown; }; =20 /** diff --git a/include/io/channel.h b/include/io/channel.h index e8cdadb0b0..da2f138200 100644 --- a/include/io/channel.h +++ b/include/io/channel.h @@ -51,9 +51,9 @@ enum QIOChannelFeature { typedef enum QIOChannelShutdown QIOChannelShutdown; =20 enum QIOChannelShutdown { - QIO_CHANNEL_SHUTDOWN_BOTH, - QIO_CHANNEL_SHUTDOWN_READ, - QIO_CHANNEL_SHUTDOWN_WRITE, + QIO_CHANNEL_SHUTDOWN_READ =3D 1, + QIO_CHANNEL_SHUTDOWN_WRITE =3D 2, + QIO_CHANNEL_SHUTDOWN_BOTH =3D 3, }; =20 typedef gboolean (*QIOChannelFunc)(QIOChannel *ioc, diff --git a/io/channel-tls.c b/io/channel-tls.c index 9628e6fa47..c98ead21b0 100644 --- a/io/channel-tls.c +++ b/io/channel-tls.c @@ -275,6 +275,9 @@ static ssize_t qio_channel_tls_readv(QIOChannel *ioc, } else { return QIO_CHANNEL_ERR_BLOCK; } + } else if (errno =3D=3D ECONNABORTED && + (tioc->shutdown & QIO_CHANNEL_SHUTDOWN_READ)) { + return 0; } =20 error_setg_errno(errp, errno, @@ -357,6 +360,8 @@ static int qio_channel_tls_shutdown(QIOChannel *ioc, { QIOChannelTLS *tioc =3D QIO_CHANNEL_TLS(ioc); =20 + tioc->shutdown |=3D how; + return qio_channel_shutdown(tioc->master, how, errp); } =20 --=20 2.19.1