From patchwork Mon Dec 21 15:42:22 2015 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: =?utf-8?q?Daniel_P=2E_Berrang=C3=A9?= X-Patchwork-Id: 559584 Return-Path: X-Original-To: incoming@patchwork.ozlabs.org Delivered-To: patchwork-incoming@bilbo.ozlabs.org Received: from lists.gnu.org (lists.gnu.org [IPv6:2001:4830:134:3::11]) (using TLSv1 with cipher AES256-SHA (256/256 bits)) (No client certificate requested) by ozlabs.org (Postfix) with ESMTPS id 44CB114018C for ; Tue, 22 Dec 2015 02:43:17 +1100 (AEDT) Received: from localhost ([::1]:45668 helo=lists.gnu.org) by lists.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1aB2cF-0000K4-2q for incoming@patchwork.ozlabs.org; Mon, 21 Dec 2015 10:43:15 -0500 Received: from eggs.gnu.org ([2001:4830:134:3::10]:53603) by lists.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1aB2bb-0007fX-Jp for qemu-devel@nongnu.org; Mon, 21 Dec 2015 10:42:36 -0500 Received: from Debian-exim by eggs.gnu.org with spam-scanned (Exim 4.71) (envelope-from ) id 1aB2ba-0000gV-8r for qemu-devel@nongnu.org; Mon, 21 Dec 2015 10:42:35 -0500 Received: from mx1.redhat.com ([209.132.183.28]:37393) by eggs.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1aB2ba-0000gJ-0z for qemu-devel@nongnu.org; Mon, 21 Dec 2015 10:42:34 -0500 Received: from int-mx09.intmail.prod.int.phx2.redhat.com (int-mx09.intmail.prod.int.phx2.redhat.com [10.5.11.22]) by mx1.redhat.com (Postfix) with ESMTPS id A39FA1454 for ; Mon, 21 Dec 2015 15:42:33 +0000 (UTC) Received: from t530wlan.home.berrange.com.com (vpn1-5-146.ams2.redhat.com [10.36.5.146]) by int-mx09.intmail.prod.int.phx2.redhat.com (8.14.4/8.14.4) with ESMTP id tBLFgSKU023043; Mon, 21 Dec 2015 10:42:32 -0500 From: "Daniel P. Berrange" To: qemu-devel@nongnu.org Date: Mon, 21 Dec 2015 15:42:22 +0000 Message-Id: <1450712543-11629-4-git-send-email-berrange@redhat.com> In-Reply-To: <1450712543-11629-1-git-send-email-berrange@redhat.com> References: <1450712543-11629-1-git-send-email-berrange@redhat.com> X-Scanned-By: MIMEDefang 2.68 on 10.5.11.22 X-detected-operating-system: by eggs.gnu.org: GNU/Linux 3.x X-Received-From: 209.132.183.28 Cc: Paolo Bonzini Subject: [Qemu-devel] [PATCH v2 3/4] char: don't assume telnet initialization will not block X-BeenThere: qemu-devel@nongnu.org X-Mailman-Version: 2.1.14 Precedence: list List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Errors-To: qemu-devel-bounces+incoming=patchwork.ozlabs.org@nongnu.org Sender: qemu-devel-bounces+incoming=patchwork.ozlabs.org@nongnu.org The current code for doing telnet initialization is writing to a socket without checking the return status. While it is highly unlikely to be a problem when writing to a bare socket, as the buffers are large enough to prevent blocking, this cannot be assumed safe with TLS sockets. So write the telnet initialization code into a memory buffer and then use an I/O watch to fully send the data. Signed-off-by: Daniel P. Berrange --- qemu-char.c | 85 ++++++++++++++++++++++++++++++++++++++++++++++++------------- 1 file changed, 67 insertions(+), 18 deletions(-) diff --git a/qemu-char.c b/qemu-char.c index bd23b7b..9f0fef1 100644 --- a/qemu-char.c +++ b/qemu-char.c @@ -2833,19 +2833,68 @@ static void tcp_chr_update_read_handler(CharDriverState *chr) } } -#define IACSET(x,a,b,c) x[0] = a; x[1] = b; x[2] = c; -static void tcp_chr_telnet_init(QIOChannel *ioc) +typedef struct { + CharDriverState *chr; + char buf[12]; + size_t buflen; +} TCPCharDriverTelnetInit; + +static gboolean tcp_chr_telnet_init_io(QIOChannel *ioc, + GIOCondition cond G_GNUC_UNUSED, + gpointer user_data) { - char buf[3]; - /* Send the telnet negotion to put telnet in binary, no echo, single char mode */ - IACSET(buf, 0xff, 0xfb, 0x01); /* IAC WILL ECHO */ - qio_channel_write(ioc, buf, 3, NULL); - IACSET(buf, 0xff, 0xfb, 0x03); /* IAC WILL Suppress go ahead */ - qio_channel_write(ioc, buf, 3, NULL); - IACSET(buf, 0xff, 0xfb, 0x00); /* IAC WILL Binary */ - qio_channel_write(ioc, buf, 3, NULL); - IACSET(buf, 0xff, 0xfd, 0x00); /* IAC DO Binary */ - qio_channel_write(ioc, buf, 3, NULL); + TCPCharDriverTelnetInit *init = user_data; + ssize_t ret; + + ret = qio_channel_write(ioc, init->buf, init->buflen, NULL); + if (ret < 0) { + if (ret == QIO_CHANNEL_ERR_BLOCK) { + ret = 0; + } else { + tcp_chr_disconnect(init->chr); + return FALSE; + } + } + init->buflen -= ret; + + if (init->buflen == 0) { + tcp_chr_connect(init->chr); + return FALSE; + } + + return TRUE; +} + +static void tcp_chr_telnet_init(CharDriverState *chr) +{ + TCPCharDriver *s = chr->opaque; + TCPCharDriverTelnetInit *init = + g_new0(TCPCharDriverTelnetInit, 1); + size_t n = 0; + + init->chr = chr; + init->buflen = 12; + +#define IACSET(x, a, b, c) \ + do { \ + x[n++] = a; \ + x[n++] = b; \ + x[n++] = c; \ + } while (0) + + /* Prep the telnet negotion to put telnet in binary, + * no echo, single char mode */ + IACSET(init->buf, 0xff, 0xfb, 0x01); /* IAC WILL ECHO */ + IACSET(init->buf, 0xff, 0xfb, 0x03); /* IAC WILL Suppress go ahead */ + IACSET(init->buf, 0xff, 0xfb, 0x00); /* IAC WILL Binary */ + IACSET(init->buf, 0xff, 0xfd, 0x00); /* IAC DO Binary */ + +#undef IACSET + + qio_channel_add_watch( + s->ioc, G_IO_OUT, + tcp_chr_telnet_init_io, + init, NULL); } static int tcp_chr_new_client(CharDriverState *chr, QIOChannelSocket *sioc) @@ -2865,7 +2914,12 @@ static int tcp_chr_new_client(CharDriverState *chr, QIOChannelSocket *sioc) g_source_remove(s->listen_tag); s->listen_tag = 0; } - tcp_chr_connect(chr); + + if (s->do_telnetopt) { + tcp_chr_telnet_init(chr); + } else { + tcp_chr_connect(chr); + } return 0; } @@ -2891,7 +2945,6 @@ static gboolean tcp_chr_accept(QIOChannel *channel, void *opaque) { CharDriverState *chr = opaque; - TCPCharDriver *s = chr->opaque; QIOChannelSocket *sioc; sioc = qio_channel_socket_accept(QIO_CHANNEL_SOCKET(channel), @@ -2900,10 +2953,6 @@ static gboolean tcp_chr_accept(QIOChannel *channel, return TRUE; } - if (s->do_telnetopt) { - tcp_chr_telnet_init(QIO_CHANNEL(sioc)); - } - tcp_chr_new_client(chr, sioc); object_unref(OBJECT(sioc));