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 777D5C61DA4 for ; Mon, 6 Mar 2023 18:57:35 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S230015AbjCFS5e (ORCPT ); Mon, 6 Mar 2023 13:57:34 -0500 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:60170 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S230091AbjCFS5O (ORCPT ); Mon, 6 Mar 2023 13:57:14 -0500 Received: from outgoing.mit.edu (outgoing-auth-1.mit.edu [18.9.28.11]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 9F79FC168 for ; Mon, 6 Mar 2023 10:56:07 -0800 (PST) Received: from cwcc.thunk.org (pool-173-48-120-46.bstnma.fios.verizon.net [173.48.120.46]) (authenticated bits=0) (User authenticated as tytso@ATHENA.MIT.EDU) by outgoing.mit.edu (8.14.7/8.12.4) with ESMTP id 326IsxMr023437 (version=TLSv1/SSLv3 cipher=DHE-RSA-AES256-GCM-SHA384 bits=256 verify=NOT); Mon, 6 Mar 2023 13:55:01 -0500 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=mit.edu; s=outgoing; t=1678128903; bh=DgMaY+QajAGrEGVRA0ZgDBNHO9jOImTkXeQduYwOks0=; h=From:To:Cc:Subject:Date; b=Sw6r+Y+GM4K4n9ahRMRXmuYlywDYglrfeSRn7nzFmpRSt9uKJCh5LEgkmRIcWmUuw mb4auqmyFlTYzOVR/Dg0TkpQZtX4J75wbLyvoddbd2zE9oATcxgV9la9PKTiyBrEkv QrBhudODNp3COfdbUxL35yleBCUUjfbKHnaGiVzfUvylUYNQFkAEl5PdMEpHA1UzPJ L8qRw6HInloW7oNsRP/V6mLgjz9zFOZlKedUvySp2unheq9SWcwGoiof6iHWWBgHj1 10lkwuqFS9VYLCmm12cfgJECmDkopByfPX3/IYb20fe6IOaGigVHTBkWsY3AtvkaZA KPVIkCQvcD5Sg== Received: by cwcc.thunk.org (Postfix, from userid 15806) id A296B15C3441; Mon, 6 Mar 2023 13:54:59 -0500 (EST) From: "Theodore Ts'o" To: Linux Kernel Developers List , Al Viro , Andrew Morton Cc: "Theodore Ts'o" Subject: [PATCH] fs: prevent out-of-bounds array speculation when closing a file descriptor Date: Mon, 6 Mar 2023 13:54:50 -0500 Message-Id: <20230306185450.1028235-1-tytso@mit.edu> X-Mailer: git-send-email 2.31.0 MIME-Version: 1.0 Content-Transfer-Encoding: 8bit Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Google-Bug-Id: 114199369 Signed-off-by: Theodore Ts'o --- I had sent this a while back, and failed to follow up when it apparently get missed. $WORK has been carrying this (or the equivalent) as an out-of-tree security patch since 2018, and now some folks are now nagging me about why hasn't this gone upstream yet... fs/file.c | 1 + 1 file changed, 1 insertion(+) diff --git a/fs/file.c b/fs/file.c index c942c89ca4cd..7893ea161d77 100644 --- a/fs/file.c +++ b/fs/file.c @@ -642,6 +642,7 @@ static struct file *pick_file(struct files_struct *files, unsigned fd) if (fd >= fdt->max_fds) return NULL; + fd = array_index_nospec(fd, fdt->max_fds); file = fdt->fd[fd]; if (file) { rcu_assign_pointer(fdt->fd[fd], NULL); -- 2.31.0