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,URIBL_BLOCKED,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 A0806C282CE for ; Wed, 24 Apr 2019 14:55:53 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 640A02084F for ; Wed, 24 Apr 2019 14:55:53 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1556117753; bh=P5cMsm+lgjxwbG1JVA3HQOf7GE0Pc5JvTYfPJ/z+bWw=; h=From:To:Cc:Subject:Date:In-Reply-To:References:List-ID:From; b=DLdN3i3lmUED1cY/wwP+OHBtGsD6r/ufqSRldytQopENALrFaSgiaD8bMGP1kxeAT 8u3ilyoOAEFh1ZaUu4TifIYFmsaXwPmYBauwoPwSuUOp2u2dguUVCTXxZ9K8cNCHb0 g54Wj5sOOCrVxQPAgqK3p27ZxqJhpN3ern1CR/mw= Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1732692AbfDXOuu (ORCPT ); Wed, 24 Apr 2019 10:50:50 -0400 Received: from mail.kernel.org ([198.145.29.99]:50028 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1732690AbfDXOut (ORCPT ); Wed, 24 Apr 2019 10:50:49 -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 CBFCC218FC; Wed, 24 Apr 2019 14:50:46 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1556117448; bh=P5cMsm+lgjxwbG1JVA3HQOf7GE0Pc5JvTYfPJ/z+bWw=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=zEQIhlvIB8BfM2YMFVt4BCxtjuhCTABK46dJzzJHbM7bpJbpymaPef3t5mLDEwVDn sKUaJ6AAtVqCD8O2n52l+4xHmRQVwh+MGUgPB4EXqWIwYPfSqsXgR9uCeWnz0OOJ6t wjl7B6VmIcvRWPzYtf/CkZRkzYKTFRXJOWIYCdCo= 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 4.9 15/28] debugfs: fix use-after-free on symlink traversal Date: Wed, 24 Apr 2019 10:49:59 -0400 Message-Id: <20190424145012.30886-15-sashal@kernel.org> X-Mailer: git-send-email 2.19.1 In-Reply-To: <20190424145012.30886-1-sashal@kernel.org> References: <20190424145012.30886-1-sashal@kernel.org> MIME-Version: 1.0 X-stable: review X-Patchwork-Hint: Ignore Content-Transfer-Encoding: 8bit Sender: stable-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: stable@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 77e9cd7a0137..20ee612017bf 100644 --- a/fs/debugfs/inode.c +++ b/fs/debugfs/inode.c @@ -170,19 +170,24 @@ 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