From patchwork Wed Nov 25 21:23:23 2015 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Markus Armbruster X-Patchwork-Id: 548776 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 4B586140306 for ; Thu, 26 Nov 2015 08:26:20 +1100 (AEDT) Received: from localhost ([::1]:47782 helo=lists.gnu.org) by lists.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1a1hZy-0001UR-5B for incoming@patchwork.ozlabs.org; Wed, 25 Nov 2015 16:26:18 -0500 Received: from eggs.gnu.org ([2001:4830:134:3::10]:40230) by lists.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1a1hXP-000519-Cp for qemu-devel@nongnu.org; Wed, 25 Nov 2015 16:23:40 -0500 Received: from Debian-exim by eggs.gnu.org with spam-scanned (Exim 4.71) (envelope-from ) id 1a1hXM-0000Wj-78 for qemu-devel@nongnu.org; Wed, 25 Nov 2015 16:23:39 -0500 Received: from mx1.redhat.com ([209.132.183.28]:54632) by eggs.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1a1hXM-0000WU-1y for qemu-devel@nongnu.org; Wed, 25 Nov 2015 16:23:36 -0500 Received: from int-mx13.intmail.prod.int.phx2.redhat.com (int-mx13.intmail.prod.int.phx2.redhat.com [10.5.11.26]) by mx1.redhat.com (Postfix) with ESMTPS id ACE293407EC for ; Wed, 25 Nov 2015 21:23:35 +0000 (UTC) Received: from blackfin.pond.sub.org (ovpn-116-45.ams2.redhat.com [10.36.116.45]) by int-mx13.intmail.prod.int.phx2.redhat.com (8.14.4/8.14.4) with ESMTP id tAPLNYPW012168 (version=TLSv1/SSLv3 cipher=DHE-RSA-AES256-GCM-SHA384 bits=256 verify=NO); Wed, 25 Nov 2015 16:23:35 -0500 Received: by blackfin.pond.sub.org (Postfix, from userid 1000) id 80DF63001855; Wed, 25 Nov 2015 22:23:33 +0100 (CET) From: Markus Armbruster To: qemu-devel@nongnu.org Date: Wed, 25 Nov 2015 22:23:23 +0100 Message-Id: <1448486613-17634-3-git-send-email-armbru@redhat.com> In-Reply-To: <1448486613-17634-1-git-send-email-armbru@redhat.com> References: <1448486613-17634-1-git-send-email-armbru@redhat.com> X-Scanned-By: MIMEDefang 2.68 on 10.5.11.26 X-detected-operating-system: by eggs.gnu.org: GNU/Linux 3.x X-Received-From: 209.132.183.28 Cc: pbonzini@redhat.com, lcapitulino@redhat.com Subject: [Qemu-devel] [PATCH v3 for-2.5 02/12] qjson: Don't crash when input exceeds nesting limit 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 We limit nesting depth and input size to defend against input triggering excessive heap or stack memory use (commit 29c75dd json-streamer: limit the maximum recursion depth and maximum token count). However, when the nesting limit is exceeded, parser_context_peek_token()'s assertion fails. Broken in commit 65c0f1e "json-parser: don't replicate tokens at each level of recursion". To reproduce stuff 1025 open braces or brackets into QMP. Fix by taking the error exit instead of the normal one. Reported-by: Eric Blake Signed-off-by: Markus Armbruster Reviewed-by: Eric Blake --- qobject/json-streamer.c | 5 +++-- 1 file changed, 3 insertions(+), 2 deletions(-) diff --git a/qobject/json-streamer.c b/qobject/json-streamer.c index dced2c7..2bd22a7 100644 --- a/qobject/json-streamer.c +++ b/qobject/json-streamer.c @@ -68,13 +68,14 @@ static void json_message_process_token(JSONLexer *lexer, QString *token, JSONTok /* Security consideration, we limit total memory allocated per object * and the maximum recursion depth that a message can force. */ - goto out_emit; + goto out_emit_bad; } return; out_emit_bad: - /* clear out token list and tell the parser to emit and error + /* + * Clear out token list and tell the parser to emit an error * indication by passing it a NULL list */ QDECREF(parser->tokens);