lkml.org 
[lkml]   [2022]   [Jan]   [31]   [last100]   RSS Feed
Views: [wrap][no wrap]   [headers]  [forward] 
 
Messages in this thread
Patch in this message
/
From
Subject[PATCH 5.10 017/100] fsnotify: fix fsnotify hooks in pseudo filesystems
Date
From: Amir Goldstein <amir73il@gmail.com>

commit 29044dae2e746949ad4b9cbdbfb248994d1dcdb4 upstream.

Commit 49246466a989 ("fsnotify: move fsnotify_nameremove() hook out of
d_delete()") moved the fsnotify delete hook before d_delete() so fsnotify
will have access to a positive dentry.

This allowed a race where opening the deleted file via cached dentry
is now possible after receiving the IN_DELETE event.

To fix the regression in pseudo filesystems, convert d_delete() calls
to d_drop() (see commit 46c46f8df9aa ("devpts_pty_kill(): don't bother
with d_delete()") and move the fsnotify hook after d_drop().

Add a missing fsnotify_unlink() hook in nfsdfs that was found during
the audit of fsnotify hooks in pseudo filesystems.

Note that the fsnotify hooks in simple_recursive_removal() follow
d_invalidate(), so they require no change.

Link: https://lore.kernel.org/r/20220120215305.282577-2-amir73il@gmail.com
Reported-by: Ivan Delalande <colona@arista.com>
Link: https://lore.kernel.org/linux-fsdevel/YeNyzoDM5hP5LtGW@visor/
Fixes: 49246466a989 ("fsnotify: move fsnotify_nameremove() hook out of d_delete()")
Cc: stable@vger.kernel.org # v5.3+
Signed-off-by: Amir Goldstein <amir73il@gmail.com>
Signed-off-by: Jan Kara <jack@suse.cz>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
---
fs/configfs/dir.c | 6 +++---
fs/devpts/inode.c | 2 +-
fs/nfsd/nfsctl.c | 5 +++--
net/sunrpc/rpc_pipe.c | 4 ++--
4 files changed, 9 insertions(+), 8 deletions(-)

--- a/fs/configfs/dir.c
+++ b/fs/configfs/dir.c
@@ -1805,8 +1805,8 @@ void configfs_unregister_group(struct co
configfs_detach_group(&group->cg_item);
d_inode(dentry)->i_flags |= S_DEAD;
dont_mount(dentry);
+ d_drop(dentry);
fsnotify_rmdir(d_inode(parent), dentry);
- d_delete(dentry);
inode_unlock(d_inode(parent));

dput(dentry);
@@ -1947,10 +1947,10 @@ void configfs_unregister_subsystem(struc
configfs_detach_group(&group->cg_item);
d_inode(dentry)->i_flags |= S_DEAD;
dont_mount(dentry);
- fsnotify_rmdir(d_inode(root), dentry);
inode_unlock(d_inode(dentry));

- d_delete(dentry);
+ d_drop(dentry);
+ fsnotify_rmdir(d_inode(root), dentry);

inode_unlock(d_inode(root));

--- a/fs/devpts/inode.c
+++ b/fs/devpts/inode.c
@@ -621,8 +621,8 @@ void devpts_pty_kill(struct dentry *dent

dentry->d_fsdata = NULL;
drop_nlink(dentry->d_inode);
- fsnotify_unlink(d_inode(dentry->d_parent), dentry);
d_drop(dentry);
+ fsnotify_unlink(d_inode(dentry->d_parent), dentry);
dput(dentry); /* d_alloc_name() in devpts_pty_new() */
}

--- a/fs/nfsd/nfsctl.c
+++ b/fs/nfsd/nfsctl.c
@@ -1247,7 +1247,8 @@ static void nfsdfs_remove_file(struct in
clear_ncl(d_inode(dentry));
dget(dentry);
ret = simple_unlink(dir, dentry);
- d_delete(dentry);
+ d_drop(dentry);
+ fsnotify_unlink(dir, dentry);
dput(dentry);
WARN_ON_ONCE(ret);
}
@@ -1336,8 +1337,8 @@ void nfsd_client_rmdir(struct dentry *de
dget(dentry);
ret = simple_rmdir(dir, dentry);
WARN_ON_ONCE(ret);
+ d_drop(dentry);
fsnotify_rmdir(dir, dentry);
- d_delete(dentry);
dput(dentry);
inode_unlock(dir);
}
--- a/net/sunrpc/rpc_pipe.c
+++ b/net/sunrpc/rpc_pipe.c
@@ -599,9 +599,9 @@ static int __rpc_rmdir(struct inode *dir

dget(dentry);
ret = simple_rmdir(dir, dentry);
+ d_drop(dentry);
if (!ret)
fsnotify_rmdir(dir, dentry);
- d_delete(dentry);
dput(dentry);
return ret;
}
@@ -612,9 +612,9 @@ static int __rpc_unlink(struct inode *di

dget(dentry);
ret = simple_unlink(dir, dentry);
+ d_drop(dentry);
if (!ret)
fsnotify_unlink(dir, dentry);
- d_delete(dentry);
dput(dentry);
return ret;
}

\
 
 \ /
  Last update: 2022-01-31 12:06    [W:0.363 / U:0.056 seconds]
©2003-2020 Jasper Spaans|hosted at Digital Ocean and TransIP|Read the blog|Advertise on this site