From nobody Thu Nov 6 04:17:59 2025 Delivered-To: importer@patchew.org Received-SPF: pass (zoho.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; Authentication-Results: mx.zohomail.com; spf=pass (zoho.com: domain of gnu.org designates 209.51.188.17 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 (lists.gnu.org [209.51.188.17]) by mx.zohomail.com with SMTPS id 1550175864425210.42803865216206; Thu, 14 Feb 2019 12:24:24 -0800 (PST) Received: from localhost ([127.0.0.1]:54536 helo=lists.gnu.org) by lists.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1guNYS-0002i3-Bb for importer@patchew.org; Thu, 14 Feb 2019 15:24:20 -0500 Received: from eggs.gnu.org ([209.51.188.92]:42647) by lists.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1guNUN-0008Ml-DV for qemu-devel@nongnu.org; Thu, 14 Feb 2019 15:20:08 -0500 Received: from Debian-exim by eggs.gnu.org with spam-scanned (Exim 4.71) (envelope-from ) id 1guNUI-0005BC-Ps for qemu-devel@nongnu.org; Thu, 14 Feb 2019 15:20:05 -0500 Received: from mx1.redhat.com ([209.132.183.28]:54360) by eggs.gnu.org with esmtps (TLS1.0:DHE_RSA_AES_256_CBC_SHA1:32) (Exim 4.71) (envelope-from ) id 1guNUI-00059N-Al for qemu-devel@nongnu.org; Thu, 14 Feb 2019 15:20:02 -0500 Received: from smtp.corp.redhat.com (int-mx08.intmail.prod.int.phx2.redhat.com [10.5.11.23]) (using TLSv1.2 with cipher AECDH-AES256-SHA (256/256 bits)) (No client certificate requested) by mx1.redhat.com (Postfix) with ESMTPS id 5C11481259; Thu, 14 Feb 2019 20:20:01 +0000 (UTC) Received: from x1w.redhat.com (ovpn-204-144.brq.redhat.com [10.40.204.144]) by smtp.corp.redhat.com (Postfix) with ESMTPS id 3E82D19C65; Thu, 14 Feb 2019 20:19:58 +0000 (UTC) From: =?UTF-8?q?Philippe=20Mathieu-Daud=C3=A9?= To: Prasad J Pandit , =?UTF-8?q?Marc-Andr=C3=A9=20Lureau?= , qemu-devel@nongnu.org, Paolo Bonzini Date: Thu, 14 Feb 2019 21:19:32 +0100 Message-Id: <20190214201939.494-3-philmd@redhat.com> In-Reply-To: <20190214201939.494-1-philmd@redhat.com> References: <20190214201939.494-1-philmd@redhat.com> MIME-Version: 1.0 X-Scanned-By: MIMEDefang 2.84 on 10.5.11.23 X-Greylist: Sender IP whitelisted, not delayed by milter-greylist-4.5.16 (mx1.redhat.com [10.5.110.25]); Thu, 14 Feb 2019 20:20:01 +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 v2 2/9] ccid-card-passthru: Replace never trigger if statement by an assertion 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: , Cc: =?UTF-8?q?Philippe=20Mathieu-Daud=C3=A9?= , Gerd Hoffmann , Arash Tohidi Chafi Errors-To: qemu-devel-bounces+importer=patchew.org@nongnu.org Sender: "Qemu-devel" Content-Type: text/plain; charset="utf-8" The right side of the comparison is the return value of can_read(): VSCARD_IN_SIZE - card->vscard_in_pos. Since the 'size' argument of chardev::read() is bound to what chardev::can_read() returns, this condition can never happen. Add an assertion, which will always fail if card->vscard_in_pos >=3D VSCARD_IN_SIZE), since size > 0. This is a quick fix for CVE-2018-18438 "Integer overflow in ccid_card_vscard_read() allows memory corruption". Fixes: CVE-2018-18438 Reported-by: Arash Tohidi Chafi Suggested-by: Paolo Bonzini Signed-off-by: Philippe Mathieu-Daud=C3=A9 --- hw/usb/ccid-card-passthru.c | 14 +------------- 1 file changed, 1 insertion(+), 13 deletions(-) diff --git a/hw/usb/ccid-card-passthru.c b/hw/usb/ccid-card-passthru.c index 8bb1314f49..1676b5fc05 100644 --- a/hw/usb/ccid-card-passthru.c +++ b/hw/usb/ccid-card-passthru.c @@ -264,24 +264,12 @@ static void ccid_card_vscard_handle_message(PassthruS= tate *card, } } =20 -static void ccid_card_vscard_drop_connection(PassthruState *card) -{ - qemu_chr_fe_deinit(&card->cs, true); - card->vscard_in_pos =3D card->vscard_in_hdr =3D 0; -} - static void ccid_card_vscard_read(void *opaque, const uint8_t *buf, int si= ze) { PassthruState *card =3D opaque; VSCMsgHeader *hdr; =20 - if (card->vscard_in_pos + size > VSCARD_IN_SIZE) { - error_report("no room for data: pos %u + size %d > %" PRId64 "." - " dropping connection.", - card->vscard_in_pos, size, VSCARD_IN_SIZE); - ccid_card_vscard_drop_connection(card); - return; - } + assert(size <=3D VSCARD_IN_SIZE - card->vscard_in_pos); assert(card->vscard_in_hdr < VSCARD_IN_SIZE); memcpy(card->vscard_in_data + card->vscard_in_pos, buf, size); card->vscard_in_pos +=3D size; --=20 2.20.1