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 4A594C433F5 for ; Tue, 9 Nov 2021 01:30:09 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 3397A610A8 for ; Tue, 9 Nov 2021 01:30:09 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S243183AbhKIBcw (ORCPT ); Mon, 8 Nov 2021 20:32:52 -0500 Received: from mail.kernel.org ([198.145.29.99]:55972 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S241935AbhKIBZc (ORCPT ); Mon, 8 Nov 2021 20:25:32 -0500 Received: by mail.kernel.org (Postfix) with ESMTPSA id BEBBD61A7A; Tue, 9 Nov 2021 01:09:59 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1636420200; bh=zqqkFx/omr5n5IvJLSH3YWicnLaayEf/zl3DEO8ju6o=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=lNzf8J2FaIBqq2pFCDqXwrqjCqFqu/QBCe4dWh4Fx0Xdq3CvQFUptMftTahRzeerk +3gap8W2BXj6slvNLiY+5AJSxBxdPk7OtAV8MJJRDDdmqjZgmCKoav/5woLTV5i5sd FdhkvwtP4GxusigzHYj7calmrC4Hky4nCl4dDkBwiAhktFGX7niPnJOpeR8qEq1wqH UhiEu4GSMkwtFQJqyY9/E7eheDIObLs1G/6hv9UXJ2Rm3fxzI6tZPoc3z/vOa5VE+m EeEIYz3v+ZsZ4xlEVygCfnx3a+/AzsSUcNdcNYsR+KXxLOUOVnU5OiY1rWSkQ9bYHk APsc08jcyWcSg== 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, ojeda@kernel.org Subject: [PATCH AUTOSEL 4.4 22/30] lib/xz: Validate the value before assigning it to an enum variable Date: Mon, 8 Nov 2021 20:09:10 -0500 Message-Id: <20211109010918.1192063-22-sashal@kernel.org> X-Mailer: git-send-email 2.33.0 In-Reply-To: <20211109010918.1192063-1-sashal@kernel.org> References: <20211109010918.1192063-1-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