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 X-Spam-Level: X-Spam-Status: No, score=-9.0 required=3.0 tests=DKIM_SIGNED,DKIM_VALID, HEADER_FROM_DIFFERENT_DOMAINS,INCLUDES_PATCH,MAILING_LIST_MULTI,SIGNED_OFF_BY, SPF_HELO_NONE,SPF_PASS,T_DKIMWL_WL_HIGH,URIBL_BLOCKED,USER_AGENT_GIT autolearn=ham autolearn_force=no version=3.4.0 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id 62652C282DD for ; Thu, 23 May 2019 19:42:32 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 2F8AC20881 for ; Thu, 23 May 2019 19:42:32 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1558640552; bh=lXNckAZnpcx/r52Bhu7DZWMItin9YE9HIlmcNz015hY=; h=From:To:Cc:Subject:Date:In-Reply-To:References:List-ID:From; b=sztAwlQSfoFydm2lUk0njQxUNxKiTSCJN6/MKaV0hSSRyQpXOJgA1D5AXYfuRWZRW fz/34+MeOqTDJKH8tfn4vNB3ax0eeOLUImGQHHa9VQFZCHW0I3G7SsRSfKWi4v/8CI uvefqM7rskjLQFV3v+tkNRb6rZvEHxWwuuNxRY7M= Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S2390324AbfEWTma (ORCPT ); Thu, 23 May 2019 15:42:30 -0400 Received: from mail.kernel.org ([198.145.29.99]:54782 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S2389379AbfEWTTA (ORCPT ); Thu, 23 May 2019 15:19:00 -0400 Received: from localhost (83-86-89-107.cable.dynamic.v4.ziggo.nl [83.86.89.107]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by mail.kernel.org (Postfix) with ESMTPSA id 84D7F20863; Thu, 23 May 2019 19:18:59 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1558639140; bh=lXNckAZnpcx/r52Bhu7DZWMItin9YE9HIlmcNz015hY=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=byIJa+sKc7iY/E6dfS/cmuEsqGMmVd5ACTWE7OmQjOdRoEQNx0aSNd4Jo4SdhvOSD leL7NZx85kPeKqP7ytP8APCiEDHXw1f9WNKdcCYXQVy9qJ3+/PIUFkPEQ2nOUGG3Un C2gezRZiTqlCNAJFiXFezQ/k3vARp8RtAjbrRReM= From: Greg Kroah-Hartman To: linux-kernel@vger.kernel.org Cc: Greg Kroah-Hartman , stable@vger.kernel.org, Al Viro , Sasha Levin Subject: [PATCH 4.19 092/114] securityfs: fix use-after-free on symlink traversal Date: Thu, 23 May 2019 21:06:31 +0200 Message-Id: <20190523181739.782821877@linuxfoundation.org> X-Mailer: git-send-email 2.21.0 In-Reply-To: <20190523181731.372074275@linuxfoundation.org> References: <20190523181731.372074275@linuxfoundation.org> User-Agent: quilt/0.66 MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org [ Upstream commit 46c874419652bbefdfed17420fd6e88d8a31d9ec ] symlink body shouldn't be freed without an RCU delay. Switch securityfs to ->destroy_inode() and use of call_rcu(); free both the inode and symlink body in the callback. Signed-off-by: Al Viro Signed-off-by: Sasha Levin --- security/inode.c | 13 +++++++++---- 1 file changed, 9 insertions(+), 4 deletions(-) diff --git a/security/inode.c b/security/inode.c index 8dd9ca8848e43..829f15672e01f 100644 --- a/security/inode.c +++ b/security/inode.c @@ -26,17 +26,22 @@ static struct vfsmount *mount; static int mount_count; -static void securityfs_evict_inode(struct inode *inode) +static void securityfs_i_callback(struct rcu_head *head) { - truncate_inode_pages_final(&inode->i_data); - clear_inode(inode); + struct inode *inode = container_of(head, struct inode, i_rcu); if (S_ISLNK(inode->i_mode)) kfree(inode->i_link); + free_inode_nonrcu(inode); +} + +static void securityfs_destroy_inode(struct inode *inode) +{ + call_rcu(&inode->i_rcu, securityfs_i_callback); } static const struct super_operations securityfs_super_operations = { .statfs = simple_statfs, - .evict_inode = securityfs_evict_inode, + .destroy_inode = securityfs_destroy_inode, }; static int fill_super(struct super_block *sb, void *data, int silent) -- 2.20.1