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 0ED32C4321E for ; Tue, 9 Nov 2021 01:25:09 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id EE1D1610A3 for ; Tue, 9 Nov 2021 01:25:08 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S243581AbhKIB1t (ORCPT ); Mon, 8 Nov 2021 20:27:49 -0500 Received: from mail.kernel.org ([198.145.29.99]:50108 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S243201AbhKIBXO (ORCPT ); Mon, 8 Nov 2021 20:23:14 -0500 Received: by mail.kernel.org (Postfix) with ESMTPSA id 1843F61A7E; Tue, 9 Nov 2021 01:08:51 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1636420131; bh=zqqkFx/omr5n5IvJLSH3YWicnLaayEf/zl3DEO8ju6o=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=Hg1voDNqvLlpq40bDjYe1iJZHR2op8q+7m+InNZvfKNUp140t2P1JxlgLdJFaN/ER /zFZCAoJy3yitoSEzKUfXEBvUq9eHEbUkP4vte82fPZfmESu280PRokt47Dn3x+Kau 6YasNdA2LOlrj5VKDs2yAjVEWBrZvec3Yg3UmwbRCkfTHmlR0IBqaW1UUzKPkbWre1 5q8mNOqe86IX/dBdzNmJ0Gb0RhsJ2xPtnWaBk4ntWYlIP3XJPpsV1gIek/5JN7y/OW ez8339bN80nus4znJr6GWPDPnez8OlHFC9Qy380CuCHAjt+XWiHQHvH5l7TpphbLYr yWwoG4SqrpmQQ== From: Sasha Levin To: linux-kernel@vger.kernel.org, stable@vger.kernel.org Cc: Lasse Collin , Gao Xiang , Sasha Levin , gustavoars@kernel.org, ndesaulniers@google.com, nathan@kernel.org Subject: [PATCH AUTOSEL 4.9 23/33] lib/xz: Validate the value before assigning it to an enum variable Date: Mon, 8 Nov 2021 20:07:57 -0500 Message-Id: <20211109010807.1191567-23-sashal@kernel.org> X-Mailer: git-send-email 2.33.0 In-Reply-To: <20211109010807.1191567-1-sashal@kernel.org> References: <20211109010807.1191567-1-sashal@kernel.org> MIME-Version: 1.0 X-stable: review X-Patchwork-Hint: Ignore 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 ac809b1e64f78..9e5b9ab537fea 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