From patchwork Tue Jan 18 16:05:51 2022 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Greg Kroah-Hartman X-Patchwork-Id: 533512 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 vger.kernel.org (vger.kernel.org [23.128.96.18]) by smtp.lore.kernel.org (Postfix) with ESMTP id 91D8FC43217 for ; Tue, 18 Jan 2022 16:09:59 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S235857AbiARQJ6 (ORCPT ); Tue, 18 Jan 2022 11:09:58 -0500 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:51686 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1347025AbiARQJQ (ORCPT ); Tue, 18 Jan 2022 11:09:16 -0500 Received: from dfw.source.kernel.org (dfw.source.kernel.org [IPv6:2604:1380:4641:c500::1]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 33F23C061751; Tue, 18 Jan 2022 08:09:02 -0800 (PST) Received: from smtp.kernel.org (relay.kernel.org [52.25.139.140]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by dfw.source.kernel.org (Postfix) with ESMTPS id C53F7612EB; Tue, 18 Jan 2022 16:09:01 +0000 (UTC) Received: by smtp.kernel.org (Postfix) with ESMTPSA id 85CDBC00446; Tue, 18 Jan 2022 16:09:00 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=linuxfoundation.org; s=korg; t=1642522141; bh=dnJnBqqXqjmuHagT1/YZePw1qawm1NKxJlMD0JTwrhg=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=oHL8l26A2GNno/ZLQ26m7s1/4+Ez/Hmp28S+wXxxXTSjUlnMQscYHRSzWzVUZUVPC +o4dB6OolgJvrcmILeNM78bnJjXHnaFpr0pXJD46zycjH38FFzML/LlDq9TDSSi/z5 8YbN5TYFs35PXGFIFmnBBsFCVPY5beSnIciGT1QI= From: Greg Kroah-Hartman To: linux-kernel@vger.kernel.org Cc: Greg Kroah-Hartman , stable@vger.kernel.org, Jamie Hill-Daniel , William Liu , Salvatore Bonaccorso , Thadeu Lima de Souza Cascardo , Dan Carpenter , Al Viro , Linus Torvalds Subject: [PATCH 5.15 05/28] vfs: fs_context: fix up param length parsing in legacy_parse_param Date: Tue, 18 Jan 2022 17:05:51 +0100 Message-Id: <20220118160452.056787467@linuxfoundation.org> X-Mailer: git-send-email 2.34.1 In-Reply-To: <20220118160451.879092022@linuxfoundation.org> References: <20220118160451.879092022@linuxfoundation.org> User-Agent: quilt/0.66 MIME-Version: 1.0 Precedence: bulk List-ID: X-Mailing-List: stable@vger.kernel.org From: Jamie Hill-Daniel commit 722d94847de29310e8aa03fcbdb41fc92c521756 upstream. The "PAGE_SIZE - 2 - size" calculation in legacy_parse_param() is an unsigned type so a large value of "size" results in a high positive value instead of a negative value as expected. Fix this by getting rid of the subtraction. Signed-off-by: Jamie Hill-Daniel Signed-off-by: William Liu Tested-by: Salvatore Bonaccorso Tested-by: Thadeu Lima de Souza Cascardo Acked-by: Dan Carpenter Acked-by: Al Viro Signed-off-by: Linus Torvalds Signed-off-by: Greg Kroah-Hartman --- fs/fs_context.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) --- a/fs/fs_context.c +++ b/fs/fs_context.c @@ -548,7 +548,7 @@ static int legacy_parse_param(struct fs_ param->key); } - if (len > PAGE_SIZE - 2 - size) + if (size + len + 2 > PAGE_SIZE) return invalf(fc, "VFS: Legacy: Cumulative options too large"); if (strchr(param->key, ',') || (param->type == fs_value_is_string &&