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=-9.1 required=3.0 tests=DKIMWL_WL_HIGH,DKIM_SIGNED, DKIM_VALID,DKIM_VALID_AU,INCLUDES_PATCH,MAILING_LIST_MULTI,SIGNED_OFF_BY, SPF_PASS,USER_AGENT_GIT autolearn=unavailable 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 1EDF7C282E1 for ; Wed, 24 Apr 2019 14:52:16 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id D5D1A218FC for ; Wed, 24 Apr 2019 14:52:15 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1556117536; bh=tff5uGrH/1bHPED0EJUJDAbfpZSRRcamXPQVBN2MA6w=; h=From:To:Cc:Subject:Date:In-Reply-To:References:List-ID:From; b=z+I500e9YjhA/5NPyKrDRYBAmVS3pJ0he0qaE/gfS2SUQGurMMXMSRHKgbobkHGkg S2H4arXkAMNNHrSoYr3A66ghdyUse9E0TItiV11qOWsS4ymxKC0Yed2x10pKenCYD0 eTran08n3qpsCuBgk4wcSRTGsF/84xfIAOnFsfbU= Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1732390AbfDXOwL (ORCPT ); Wed, 24 Apr 2019 10:52:11 -0400 Received: from mail.kernel.org ([198.145.29.99]:51608 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1732897AbfDXOwK (ORCPT ); Wed, 24 Apr 2019 10:52:10 -0400 Received: from sasha-vm.mshome.net (c-73-47-72-35.hsd1.nh.comcast.net [73.47.72.35]) (using TLSv1.2 with cipher ECDHE-RSA-AES128-GCM-SHA256 (128/128 bits)) (No client certificate requested) by mail.kernel.org (Postfix) with ESMTPSA id 8A8BE218FD; Wed, 24 Apr 2019 14:52:07 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1556117529; bh=tff5uGrH/1bHPED0EJUJDAbfpZSRRcamXPQVBN2MA6w=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=XKOmdIVfVpELi5EeeybOSTsmTZu34Jg+XqdjvmtLOS5FwemWohsT2KE5ndA4Ken1D 2Cd6UjKVmkcnijlRGqpkbAqUVmjjvx8EGXNOqFUy2bnJgTSaFzYvsSkflM4XPYFXkN HPYcL/5fXcJ2uOmMVmUM0jvTu8exT23MUAXeA8BE= From: Sasha Levin To: linux-kernel@vger.kernel.org, stable@vger.kernel.org Cc: Al Viro , Sasha Levin , netdev@vger.kernel.org, bpf@vger.kernel.org Subject: [PATCH AUTOSEL 4.4 06/15] debugfs: fix use-after-free on symlink traversal Date: Wed, 24 Apr 2019 10:51:43 -0400 Message-Id: <20190424145152.31351-6-sashal@kernel.org> X-Mailer: git-send-email 2.19.1 In-Reply-To: <20190424145152.31351-1-sashal@kernel.org> References: <20190424145152.31351-1-sashal@kernel.org> MIME-Version: 1.0 X-stable: review X-Patchwork-Hint: Ignore Content-Transfer-Encoding: 8bit Sender: netdev-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: netdev@vger.kernel.org From: Al Viro [ Upstream commit 93b919da64c15b90953f96a536e5e61df896ca57 ] symlink body shouldn't be freed without an RCU delay. Switch debugfs to ->destroy_inode() and use of call_rcu(); free both the inode and symlink body in the callback. Similar to solution for bpf, only here it's even more obvious that ->evict_inode() can be dropped. Signed-off-by: Al Viro Signed-off-by: Sasha Levin --- fs/debugfs/inode.c | 13 +++++++++---- 1 file changed, 9 insertions(+), 4 deletions(-) diff --git a/fs/debugfs/inode.c b/fs/debugfs/inode.c index 22fe11baef2b..3530e1c3ff56 100644 --- a/fs/debugfs/inode.c +++ b/fs/debugfs/inode.c @@ -164,19 +164,24 @@ static int debugfs_show_options(struct seq_file *m, struct dentry *root) return 0; } -static void debugfs_evict_inode(struct inode *inode) +static void debugfs_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 debugfs_destroy_inode(struct inode *inode) +{ + call_rcu(&inode->i_rcu, debugfs_i_callback); } static const struct super_operations debugfs_super_operations = { .statfs = simple_statfs, .remount_fs = debugfs_remount, .show_options = debugfs_show_options, - .evict_inode = debugfs_evict_inode, + .destroy_inode = debugfs_destroy_inode, }; static struct vfsmount *debugfs_automount(struct path *path) -- 2.19.1