From nobody Tue Nov 26 09:32:12 2024 Delivered-To: importer@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+importer=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 1709458471586199.8021174204681; Sun, 3 Mar 2024 01:34:31 -0800 (PST) Received: from localhost ([::1] helo=lists1p.gnu.org) by lists.gnu.org with esmtp (Exim 4.90_1) (envelope-from ) id 1rgiDl-0001To-5q; Sun, 03 Mar 2024 04:33:25 -0500 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 1rgiDf-0001SP-7o; Sun, 03 Mar 2024 04:33:20 -0500 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 1rgiDd-0006WN-FS; Sun, 03 Mar 2024 04:33:18 -0500 Received: from tsrv.corpit.ru (tsrv.tls.msk.ru [192.168.177.2]) by isrv.corpit.ru (Postfix) with ESMTP id 41441527D0; Sun, 3 Mar 2024 12:33:48 +0300 (MSK) Received: from tls.msk.ru (mjt.wg.tls.msk.ru [192.168.177.130]) by tsrv.corpit.ru (Postfix) with SMTP id B5E1F8E8CC; Sun, 3 Mar 2024 12:33:04 +0300 (MSK) Received: (nullmailer pid 1357016 invoked by uid 1000); Sun, 03 Mar 2024 09:33:04 -0000 From: Michael Tokarev To: qemu-devel@nongnu.org Cc: qemu-stable@nongnu.org, Thomas Huth , =?UTF-8?q?Daniel=20P=2E=20Berrang=C3=A9?= , Antoine Damhet , =?UTF-8?q?Marc-Andr=C3=A9=20Lureau?= , Michael Tokarev Subject: [Stable-8.2.2 82/82] chardev/char-socket: Fix TLS io channels sending too much data to the backend Date: Sun, 3 Mar 2024 12:33:00 +0300 Message-Id: <20240303093304.1356981-4-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+importer=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, T_SCC_BODY_TEXT_LINE=-0.01 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+importer=patchew.org@nongnu.org Sender: qemu-devel-bounces+importer=patchew.org@nongnu.org X-ZM-MESSAGEID: 1709458471861100001 From: Thomas Huth Commit ffda5db65a ("io/channel-tls: fix handling of bigger read buffers") changed the behavior of the TLS io channels to schedule a second reading attempt if there is still incoming data pending. This caused a regression with backends like the sclpconsole that check in their read function that the sender does not try to write more bytes to it than the device can currently handle. The problem can be reproduced like this: 1) In one terminal, do this: mkdir qemu-pki cd qemu-pki openssl genrsa 2048 > ca-key.pem openssl req -new -x509 -nodes -days 365000 -key ca-key.pem -out ca-cert.p= em # enter some dummy value for the cert openssl genrsa 2048 > server-key.pem openssl req -new -x509 -nodes -days 365000 -key server-key.pem \ -out server-cert.pem # enter some other dummy values for the cert gnutls-serv --echo --x509cafile ca-cert.pem --x509keyfile server-key.pem \ --x509certfile server-cert.pem -p 8338 2) In another terminal, do this: wget https://download.fedoraproject.org/pub/fedora-secondary/releases/39/= Cloud/s390x/images/Fedora-Cloud-Base-39-1.5.s390x.qcow2 qemu-system-s390x -nographic -nodefaults \ -hda Fedora-Cloud-Base-39-1.5.s390x.qcow2 \ -object tls-creds-x509,id=3Dtls0,endpoint=3Dclient,verify-peer=3Dfalse,= dir=3D$PWD/qemu-pki \ -chardev socket,id=3Dtls_chardev,host=3Dlocalhost,port=3D8338,tls-creds= =3Dtls0 \ -device sclpconsole,chardev=3Dtls_chardev,id=3Dtls_serial QEMU then aborts after a second or two with: qemu-system-s390x: ../hw/char/sclpconsole.c:73: chr_read: Assertion `size <=3D SIZE_BUFFER_VT220 - scon->iov_data_len' failed. Aborted (core dumped) It looks like the second read does not trigger the chr_can_read() function to be called before the second read, which should normally always be done before sending bytes to a character device to see how much it can handle, so the s->max_size in tcp_chr_read() still contains the old value from the previous read. Let's make sure that we use the up-to-date value by calling tcp_chr_read_poll() again here. Fixes: ffda5db65a ("io/channel-tls: fix handling of bigger read buffers") Buglink: https://issues.redhat.com/browse/RHEL-24614 Reviewed-by: "Daniel P. Berrang=C3=A9" Message-ID: <20240229104339.42574-1-thuth@redhat.com> Reviewed-by: Antoine Damhet Tested-by: Antoine Damhet Reviewed-by: Marc-Andr=C3=A9 Lureau Signed-off-by: Thomas Huth (cherry picked from commit 462945cd22d2bcd233401ed3aa167d83a8e35b05) Signed-off-by: Michael Tokarev diff --git a/chardev/char-socket.c b/chardev/char-socket.c index 73947da188..034840593d 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 sizeof(buf); - if (len > s->max_size) { - len =3D s->max_size; + len =3D tcp_chr_read_poll(opaque); + if (len > sizeof(buf)) { + len =3D sizeof(buf); } 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