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 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id 4AE21C433F5 for ; Tue, 16 Nov 2021 00:58:52 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 32A3361AAA for ; Tue, 16 Nov 2021 00:58:52 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S240179AbhKPBBq (ORCPT ); Mon, 15 Nov 2021 20:01:46 -0500 Received: from mail.kernel.org ([198.145.29.99]:44644 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1343513AbhKOTVQ (ORCPT ); Mon, 15 Nov 2021 14:21:16 -0500 Received: by mail.kernel.org (Postfix) with ESMTPSA id DDDB36359C; Mon, 15 Nov 2021 18:41:10 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=linuxfoundation.org; s=korg; t=1637001671; bh=/df6E/pzX0/vPDpg042wquEswSft4/w11//V6dS6SPY=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=VDaiyDUWBHrDsDoUzLZFJxn5xygBPddtkbuNirhXpx9NxQI80P/1rcNV5H6cgaCri wUc5azNpPHsLi+/w6VR76kuvG/a0ORldMcuSUj8KKgh8CyQv4koUB0gZ5VV/hZ0ylP ptCW/oYhyISGqpB8E2RIYkxubLC25gmRTqZwmxHs= From: Greg Kroah-Hartman To: linux-kernel@vger.kernel.org Cc: Greg Kroah-Hartman , stable@vger.kernel.org, Lasse Collin , Gao Xiang , Sasha Levin Subject: [PATCH 5.15 269/917] lib/xz: Validate the value before assigning it to an enum variable Date: Mon, 15 Nov 2021 17:56:04 +0100 Message-Id: <20211115165437.897870180@linuxfoundation.org> X-Mailer: git-send-email 2.33.1 In-Reply-To: <20211115165428.722074685@linuxfoundation.org> References: <20211115165428.722074685@linuxfoundation.org> User-Agent: quilt/0.66 MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org From: Lasse Collin [ Upstream commit 4f8d7abaa413c34da9d751289849dbfb7c977d05 ] This might matter, for example, if the underlying type of enum xz_check was a signed char. In such a case the validation wouldn't have caught an unsupported header. I don't know if this problem can occur in the kernel on any arch but it's still good to fix it because some people might copy the XZ code to their own projects from Linux instead of the upstream XZ Embedded repository. This change may increase the code size by a few bytes. An alternative would have been to use an unsigned int instead of enum xz_check but using an enumeration looks cleaner. Link: https://lore.kernel.org/r/20211010213145.17462-3-xiang@kernel.org Signed-off-by: Lasse Collin Signed-off-by: Gao Xiang Signed-off-by: Sasha Levin --- lib/xz/xz_dec_stream.c | 6 +++--- 1 file changed, 3 insertions(+), 3 deletions(-) diff --git a/lib/xz/xz_dec_stream.c b/lib/xz/xz_dec_stream.c index fea86deaaa01d..683570b93a8c4 100644 --- a/lib/xz/xz_dec_stream.c +++ b/lib/xz/xz_dec_stream.c @@ -402,12 +402,12 @@ static enum xz_ret dec_stream_header(struct xz_dec *s) * we will accept other check types too, but then the check won't * be verified and a warning (XZ_UNSUPPORTED_CHECK) will be given. */ + if (s->temp.buf[HEADER_MAGIC_SIZE + 1] > XZ_CHECK_MAX) + return XZ_OPTIONS_ERROR; + s->check_type = s->temp.buf[HEADER_MAGIC_SIZE + 1]; #ifdef XZ_DEC_ANY_CHECK - if (s->check_type > XZ_CHECK_MAX) - return XZ_OPTIONS_ERROR; - if (s->check_type > XZ_CHECK_CRC32) return XZ_UNSUPPORTED_CHECK; #else -- 2.33.0