From nobody Sun Feb 8 18:19:17 2026 Delivered-To: importer@patchew.org Authentication-Results: mx.zohomail.com; dkim=pass; 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; dmarc=pass(p=none dis=none) header.from=redhat.com ARC-Seal: i=1; a=rsa-sha256; t=1664138928; cv=none; d=zohomail.com; s=zohoarc; b=PrstdsKLj7T0DmMForD5Kf5AfRmsRnIN3H+5i8pB4DCfvXvbDu0or5p5BLIJSD2QBADUIbRaKpQDD3XcR4F4lvzzD5OPku5ZaqyIkEi9KipiaxDB7xCjYfhC/o6ZNCbYiVB0QBcCsUrcp4kDxh8ENIFLCJt6nebgIGO0rxopBNg= ARC-Message-Signature: i=1; a=rsa-sha256; c=relaxed/relaxed; d=zohomail.com; s=zohoarc; t=1664138928; h=Content-Transfer-Encoding:Cc:Date:From:List-Subscribe:List-Post:List-Id:List-Archive:List-Help:List-Unsubscribe:MIME-Version:Message-ID:Sender:Subject:To; bh=G85a1UWkiVHMpqTYuu2+R25oSBYe4UWW84jebp9crDg=; b=YYXL6aC0Ucmr9HLrK6fR3dWvv3tP6NzkpVoLIl9AoZLzN1PYK1WEeuKoeMKmobVwKcy9595qSP78MVEV4vjkrKLJaGfZSHGC3n3POwAivWMof5X5z27UkI6oH2B6hJGQHyceR4cBMOfNeHDjCcGNiyqwR7yqbkdOB5DIuBIzlto= ARC-Authentication-Results: i=1; mx.zohomail.com; dkim=pass; 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; dmarc=pass header.from= (p=none dis=none) Return-Path: Received: from lists.gnu.org (lists.gnu.org [209.51.188.17]) by mx.zohomail.com with SMTPS id 166413892877978.02324369993516; Sun, 25 Sep 2022 13:48:48 -0700 (PDT) Received: from localhost ([::1]:44376 helo=lists1p.gnu.org) by lists.gnu.org with esmtp (Exim 4.90_1) (envelope-from ) id 1ocYYR-0001MF-7p for importer@patchew.org; Sun, 25 Sep 2022 16:48:47 -0400 Received: from eggs.gnu.org ([2001:470:142:3::10]:43016) by lists.gnu.org with esmtps (TLS1.2:ECDHE_RSA_AES_256_GCM_SHA384:256) (Exim 4.90_1) (envelope-from ) id 1ocYVL-0000MU-Aw for qemu-devel@nongnu.org; Sun, 25 Sep 2022 16:45:35 -0400 Received: from us-smtp-delivery-124.mimecast.com ([170.10.133.124]:31672) by eggs.gnu.org with esmtps (TLS1.2:ECDHE_RSA_AES_256_GCM_SHA384:256) (Exim 4.90_1) (envelope-from ) id 1ocYVG-0000gf-P6 for qemu-devel@nongnu.org; Sun, 25 Sep 2022 16:45:32 -0400 Received: from mimecast-mx02.redhat.com (mimecast-mx02.redhat.com [66.187.233.88]) by relay.mimecast.com with ESMTP with STARTTLS (version=TLSv1.2, cipher=TLS_ECDHE_RSA_WITH_AES_256_GCM_SHA384) id us-mta-158-i9aEtF1yN72_YCnosbxozA-1; Sun, 25 Sep 2022 16:45:24 -0400 Received: from smtp.corp.redhat.com (int-mx02.intmail.prod.int.rdu2.redhat.com [10.11.54.2]) (using TLSv1.2 with cipher AECDH-AES256-SHA (256/256 bits)) (No client certificate requested) by mimecast-mx02.redhat.com (Postfix) with ESMTPS id 4FF55101A528; Sun, 25 Sep 2022 20:45:24 +0000 (UTC) Received: from f36-work.redhat.com (unknown [10.39.192.52]) by smtp.corp.redhat.com (Postfix) with ESMTPS id 7F9CE40C6EC2; Sun, 25 Sep 2022 20:45:21 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=redhat.com; s=mimecast20190719; t=1664138728; h=from:from:reply-to:subject:subject:date:date:message-id:message-id: to:to:cc:cc:mime-version:mime-version: content-transfer-encoding:content-transfer-encoding; bh=G85a1UWkiVHMpqTYuu2+R25oSBYe4UWW84jebp9crDg=; b=DF+YUzDpwvWohuSXA0J7bWPYHHvpikYDHDIBBP2jNVsDB4wt5A4cSrwsiqFpZ0sXn5Yn5v BCtEb3G4kgi4wYXajl7tm840sEyTXCsiVjQThX4ttaBiyEKEq1zt7/sUmEZg6FAcJPkfib IrOm87YtWT0SUPkaMwO38An0ckiFLv0= X-MC-Unique: i9aEtF1yN72_YCnosbxozA-1 From: Mauro Matteo Cascella To: qemu-devel@nongnu.org Cc: mcascell@redhat.com, kraxel@redhat.com, tangpeng@qianxin.com Subject: [PATCH] ui/vnc-clipboard: fix integer underflow in vnc_client_cut_text_ext Date: Sun, 25 Sep 2022 22:45:11 +0200 Message-Id: <20220925204511.1103214-1-mcascell@redhat.com> MIME-Version: 1.0 Content-Transfer-Encoding: quoted-printable X-Scanned-By: MIMEDefang 3.1 on 10.11.54.2 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=170.10.133.124; envelope-from=mcascell@redhat.com; helo=us-smtp-delivery-124.mimecast.com X-Spam_score_int: -21 X-Spam_score: -2.2 X-Spam_bar: -- X-Spam_report: (-2.2 / 5.0 requ) BAYES_00=-1.9, DKIMWL_WL_HIGH=-0.082, DKIM_SIGNED=0.1, DKIM_VALID=-0.1, DKIM_VALID_AU=-0.1, DKIM_VALID_EF=-0.1, RCVD_IN_DNSWL_NONE=-0.0001, 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+importer=patchew.org@nongnu.org Sender: "Qemu-devel" X-ZohoMail-DKIM: pass (identity @redhat.com) X-ZM-MESSAGEID: 1664138932540100001 Content-Type: text/plain; charset="utf-8" Extended ClientCutText messages start with a 4-byte header. If len < 4, an integer underflow occurs in vnc_client_cut_text_ext. The result is used to decompress data in a while loop in inflate_buffer, leading to CPU consumption and denial of service. Prevent this by checking dlen in protocol_client_msg. Fixes: CVE-2022-3165 Fixes: 0bf41cab93e5 ("ui/vnc: clipboard support") Reported-by: TangPeng Signed-off-by: Mauro Matteo Cascella --- Extended Clipboard Pseudo-Encoding: https://github.com/rfbproto/rfbproto/blob/master/rfbproto.rst#extended-clip= board-pseudo-encoding ui/vnc.c | 11 ++++++++--- 1 file changed, 8 insertions(+), 3 deletions(-) diff --git a/ui/vnc.c b/ui/vnc.c index 6a05d06147..acb3629cd8 100644 --- a/ui/vnc.c +++ b/ui/vnc.c @@ -2442,8 +2442,8 @@ static int protocol_client_msg(VncState *vs, uint8_t = *data, size_t len) if (len =3D=3D 1) { return 8; } + uint32_t dlen =3D abs(read_s32(data, 4)); if (len =3D=3D 8) { - uint32_t dlen =3D abs(read_s32(data, 4)); if (dlen > (1 << 20)) { error_report("vnc: client_cut_text msg payload has %u byte= s" " which exceeds our limit of 1MB.", dlen); @@ -2456,8 +2456,13 @@ static int protocol_client_msg(VncState *vs, uint8_t= *data, size_t len) } =20 if (read_s32(data, 4) < 0) { - vnc_client_cut_text_ext(vs, abs(read_s32(data, 4)), - read_u32(data, 8), data + 12); + if (dlen < 4) { + error_report("vnc: malformed payload (header less than 4 b= ytes)" + " in extended clipboard pseudo-encoding."); + vnc_client_error(vs); + break; + } + vnc_client_cut_text_ext(vs, dlen, read_u32(data, 8), data + 12= ); break; } vnc_client_cut_text(vs, read_u32(data, 4), data + 8); --=20 2.37.3