From nobody Wed Nov 5 10:44:10 2025 Delivered-To: importer@patchew.org Received-SPF: pass (zoho.com: domain of gnu.org designates 208.118.235.17 as permitted sender) client-ip=208.118.235.17; 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 208.118.235.17 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 [208.118.235.17]) by mx.zohomail.com with SMTPS id 1533732356519960.1599890315997; Wed, 8 Aug 2018 05:45:56 -0700 (PDT) Received: from localhost ([::1]:43417 helo=lists.gnu.org) by lists.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1fnNqZ-0001Jb-DA for importer@patchew.org; Wed, 08 Aug 2018 08:45:51 -0400 Received: from eggs.gnu.org ([2001:4830:134:3::10]:52671) by lists.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1fnNBt-0006oq-Ur for qemu-devel@nongnu.org; Wed, 08 Aug 2018 08:03:58 -0400 Received: from Debian-exim by eggs.gnu.org with spam-scanned (Exim 4.71) (envelope-from ) id 1fnNBl-00007h-LL for qemu-devel@nongnu.org; Wed, 08 Aug 2018 08:03:49 -0400 Received: from mx3-rdu2.redhat.com ([66.187.233.73]:45422 helo=mx1.redhat.com) by eggs.gnu.org with esmtps (TLS1.0:DHE_RSA_AES_256_CBC_SHA1:32) (Exim 4.71) (envelope-from ) id 1fnNBl-00005f-77 for qemu-devel@nongnu.org; Wed, 08 Aug 2018 08:03:41 -0400 Received: from smtp.corp.redhat.com (int-mx03.intmail.prod.int.rdu2.redhat.com [10.11.54.3]) (using TLSv1.2 with cipher AECDH-AES256-SHA (256/256 bits)) (No client certificate requested) by mx1.redhat.com (Postfix) with ESMTPS id 7BFEE81663F5; Wed, 8 Aug 2018 12:03:40 +0000 (UTC) Received: from blackfin.pond.sub.org (ovpn-117-62.ams2.redhat.com [10.36.117.62]) by smtp.corp.redhat.com (Postfix) with ESMTPS id 526BA111AF00; Wed, 8 Aug 2018 12:03:40 +0000 (UTC) Received: by blackfin.pond.sub.org (Postfix, from userid 1000) id 197F1113854F; Wed, 8 Aug 2018 14:03:35 +0200 (CEST) From: Markus Armbruster To: qemu-devel@nongnu.org Date: Wed, 8 Aug 2018 14:03:26 +0200 Message-Id: <20180808120334.10970-49-armbru@redhat.com> In-Reply-To: <20180808120334.10970-1-armbru@redhat.com> References: <20180808120334.10970-1-armbru@redhat.com> X-Scanned-By: MIMEDefang 2.78 on 10.11.54.3 X-Greylist: Sender IP whitelisted, not delayed by milter-greylist-4.5.16 (mx1.redhat.com [10.11.55.8]); Wed, 08 Aug 2018 12:03:40 +0000 (UTC) X-Greylist: inspected by milter-greylist-4.5.16 (mx1.redhat.com [10.11.55.8]); Wed, 08 Aug 2018 12:03:40 +0000 (UTC) for IP:'10.11.54.3' DOMAIN:'int-mx03.intmail.prod.int.rdu2.redhat.com' HELO:'smtp.corp.redhat.com' FROM:'armbru@redhat.com' RCPT:'' X-detected-operating-system: by eggs.gnu.org: GNU/Linux 2.2.x-3.x [generic] [fuzzy] X-Received-From: 66.187.233.73 Subject: [Qemu-devel] [PATCH 48/56] json: Enforce token count and size limits more tightly 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: marcandre.lureau@redhat.com, mdroth@linux.vnet.ibm.com Errors-To: qemu-devel-bounces+importer=patchew.org@nongnu.org Sender: "Qemu-devel" X-ZohoMail: RDMRC_1 RSF_0 Z_629925259 SPT_0 Content-Transfer-Encoding: quoted-printable MIME-Version: 1.0 Content-Type: text/plain; charset="utf-8" Token count and size limits exist to guard against excessive heap usage. We check them only after we created the token on the heap. That's assigning a cowboy to the barn to lasso the horse after it has bolted. Close the barn door instead: check before we create the token. Signed-off-by: Markus Armbruster --- qobject/json-streamer.c | 36 ++++++++++++++++++------------------ 1 file changed, 18 insertions(+), 18 deletions(-) diff --git a/qobject/json-streamer.c b/qobject/json-streamer.c index 674dfe6e85..810aae521f 100644 --- a/qobject/json-streamer.c +++ b/qobject/json-streamer.c @@ -20,7 +20,7 @@ =20 #define MAX_TOKEN_SIZE (64ULL << 20) #define MAX_TOKEN_COUNT (2ULL << 20) -#define MAX_NESTING (1ULL << 10) +#define MAX_NESTING (1 << 10) =20 static void json_message_free_token(void *token, void *opaque) { @@ -71,6 +71,23 @@ void json_message_process_token(JSONLexer *lexer, GStrin= g *input, break; } =20 + /* + * Security consideration, we limit total memory allocated per object + * and the maximum recursion depth that a message can force. + */ + if (parser->token_size + input->len + 1 > MAX_TOKEN_SIZE) { + error_setg(&err, "JSON token size limit exceeded"); + goto out_emit; + } + if (g_queue_get_length(parser->tokens) + 1 > MAX_TOKEN_COUNT) { + error_setg(&err, "JSON token count limit exceeded"); + goto out_emit; + } + if (parser->bracket_count + parser->brace_count > MAX_NESTING) { + error_setg(&err, "JSON nesting depth limit exceeded"); + goto out_emit; + } + token =3D g_malloc(sizeof(JSONToken) + input->len + 1); token->type =3D type; memcpy(token->str, input->str, input->len); @@ -91,23 +108,6 @@ void json_message_process_token(JSONLexer *lexer, GStri= ng *input, goto out_emit; } =20 - /* - * Security consideration, we limit total memory allocated per object - * and the maximum recursion depth that a message can force. - */ - if (parser->token_size > MAX_TOKEN_SIZE) { - error_setg(&err, "JSON token size limit exceeded"); - goto out_emit; - } - if (g_queue_get_length(parser->tokens) > MAX_TOKEN_COUNT) { - error_setg(&err, "JSON token count limit exceeded"); - goto out_emit; - } - if (parser->bracket_count + parser->brace_count > MAX_NESTING) { - error_setg(&err, "JSON nesting depth limit exceeded"); - goto out_emit; - } - return; =20 out_emit: --=20 2.17.1