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 vger.kernel.org (vger.kernel.org [23.128.96.18]) by smtp.lore.kernel.org (Postfix) with ESMTP id 6B97BC43217 for ; Tue, 18 Jan 2022 16:12:38 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1347089AbiARQMh (ORCPT ); Tue, 18 Jan 2022 11:12:37 -0500 Received: from sin.source.kernel.org ([145.40.73.55]:41990 "EHLO sin.source.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1347401AbiARQLD (ORCPT ); Tue, 18 Jan 2022 11:11:03 -0500 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 sin.source.kernel.org (Postfix) with ESMTPS id C2E9ECE1A4E; Tue, 18 Jan 2022 16:11:00 +0000 (UTC) Received: by smtp.kernel.org (Postfix) with ESMTPSA id 93F20C00446; Tue, 18 Jan 2022 16:10:58 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=linuxfoundation.org; s=korg; t=1642522259; bh=dnJnBqqXqjmuHagT1/YZePw1qawm1NKxJlMD0JTwrhg=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=aBxGwnfgQVme841JypALmS+63AJ2TneZAXyWWPLmp6wyeKk29qAt9jJYXAcxDzxX1 O4/GeP76chNxm0rvM0s/bEshVclK+Ez3fBmk2aa1dUl5kFJ0ncQ9XTyC1vc6koGQ7u yqbutikfOZgbByPQGGZKKBYnDdFCoWOlvtKP5OBk= 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 5.16 05/28] vfs: fs_context: fix up param length parsing in legacy_parse_param Date: Tue, 18 Jan 2022 17:06:00 +0100 Message-Id: <20220118160452.579694934@linuxfoundation.org> X-Mailer: git-send-email 2.34.1 In-Reply-To: <20220118160452.384322748@linuxfoundation.org> References: <20220118160452.384322748@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: 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 &&