From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org X-Spam-Level: X-Spam-Status: No, score=-6.0 required=3.0 tests=DKIMWL_WL_HIGH,DKIM_SIGNED, DKIM_VALID,HEADER_FROM_DIFFERENT_DOMAINS,MAILING_LIST_MULTI,SIGNED_OFF_BY, SPF_PASS,USER_AGENT_GIT autolearn=unavailable autolearn_force=no version=3.4.0 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id F3989C43381 for ; Mon, 1 Apr 2019 18:04:35 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id C2DBC20883 for ; Mon, 1 Apr 2019 18:04:35 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1554141875; bh=Da7c/PE30662eWsNcrbPIAeWA4PxHjW5yKJRrx/yJV8=; h=From:To:Cc:Subject:Date:In-Reply-To:References:List-ID:From; b=OkjZ4CC+WFTIhBbC4oimd8dxwbeo15qs2YDFrIQfxrlJWkpf33KpdWP+Zh7y1tPjp EpNKa8EmZOOxodD5MeWxZt7nkH04/Z2M3O0IPG4SrY0ra4N19CI7n1ualPA9MGYR7P 2GS34u5Jk8PC4e1P/JVELO9Zwz9X2m9ZIJZHCGJo= Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1730087AbfDASE2 (ORCPT ); Mon, 1 Apr 2019 14:04:28 -0400 Received: from mail.kernel.org ([198.145.29.99]:36958 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1730649AbfDAROA (ORCPT ); Mon, 1 Apr 2019 13:14:00 -0400 Received: from localhost (83-86-89-107.cable.dynamic.v4.ziggo.nl [83.86.89.107]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by mail.kernel.org (Postfix) with ESMTPSA id 9759321473; Mon, 1 Apr 2019 17:04:02 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1554138243; bh=Da7c/PE30662eWsNcrbPIAeWA4PxHjW5yKJRrx/yJV8=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=GxxeHMt+OG3sWbAjEmBXLjhTauRqbCn0hWQaaddWe/OX5qGhlpfgLMGAhAqbLYR/L TSRSlu4HKdVv1Z+4NxtjwGH2w8zRy1e1itTgEa77/dgPpEunrvdmGupi2XHWueGsOV 15BptokuDk8FCTEiF8BqIwC+W06u1Psv/cMmBoJU= From: Greg Kroah-Hartman To: linux-kernel@vger.kernel.org Cc: Greg Kroah-Hartman , stable@vger.kernel.org, Marcel Holtmann , Johan Hedberg Subject: [PATCH 5.0 002/146] Bluetooth: Verify that l2cap_get_conf_opt provides large enough buffer Date: Mon, 1 Apr 2019 19:00:14 +0200 Message-Id: <20190401170048.645388006@linuxfoundation.org> X-Mailer: git-send-email 2.21.0 In-Reply-To: <20190401170048.449559024@linuxfoundation.org> References: <20190401170048.449559024@linuxfoundation.org> User-Agent: quilt/0.65 X-stable: review X-Patchwork-Hint: ignore MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit Sender: stable-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: stable@vger.kernel.org 5.0-stable review patch. If anyone has any objections, please let me know. ------------------ From: Marcel Holtmann commit 7c9cbd0b5e38a1672fcd137894ace3b042dfbf69 upstream. The function l2cap_get_conf_opt will return L2CAP_CONF_OPT_SIZE + opt->len as length value. The opt->len however is in control over the remote user and can be used by an attacker to gain access beyond the bounds of the actual packet. To prevent any potential leak of heap memory, it is enough to check that the resulting len calculation after calling l2cap_get_conf_opt is not below zero. A well formed packet will always return >= 0 here and will end with the length value being zero after the last option has been parsed. In case of malformed packets messing with the opt->len field the length value will become negative. If that is the case, then just abort and ignore the option. In case an attacker uses a too short opt->len value, then garbage will be parsed, but that is protected by the unknown option handling and also the option parameter size checks. Signed-off-by: Marcel Holtmann Reviewed-by: Greg Kroah-Hartman Signed-off-by: Johan Hedberg Signed-off-by: Greg Kroah-Hartman --- net/bluetooth/l2cap_core.c | 6 ++++++ 1 file changed, 6 insertions(+) --- a/net/bluetooth/l2cap_core.c +++ b/net/bluetooth/l2cap_core.c @@ -3337,6 +3337,8 @@ static int l2cap_parse_conf_req(struct l while (len >= L2CAP_CONF_OPT_SIZE) { len -= l2cap_get_conf_opt(&req, &type, &olen, &val); + if (len < 0) + break; hint = type & L2CAP_CONF_HINT; type &= L2CAP_CONF_MASK; @@ -3555,6 +3557,8 @@ static int l2cap_parse_conf_rsp(struct l while (len >= L2CAP_CONF_OPT_SIZE) { len -= l2cap_get_conf_opt(&rsp, &type, &olen, &val); + if (len < 0) + break; switch (type) { case L2CAP_CONF_MTU: @@ -3740,6 +3744,8 @@ static void l2cap_conf_rfc_get(struct l2 while (len >= L2CAP_CONF_OPT_SIZE) { len -= l2cap_get_conf_opt(&rsp, &type, &olen, &val); + if (len < 0) + break; switch (type) { case L2CAP_CONF_RFC: