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authorAmir Goldstein <amir73il@gmail.com>2022-01-20 23:53:05 +0200
committerJan Kara <jack@suse.cz>2022-01-24 14:17:02 +0100
commit29044dae2e746949ad4b9cbdbfb248994d1dcdb4 (patch)
treef7480a05b92c6d395836774ed3a52fb4bb5a3404
parenta37d9a17f099072fe4d3a9048b0321978707a918 (diff)
fsnotify: fix fsnotify hooks in pseudo filesystems
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>
-rw-r--r--fs/configfs/dir.c6
-rw-r--r--fs/devpts/inode.c2
-rw-r--r--fs/nfsd/nfsctl.c5
-rw-r--r--net/sunrpc/rpc_pipe.c4
4 files changed, 9 insertions, 8 deletions
diff --git a/fs/configfs/dir.c b/fs/configfs/dir.c
index 1466b5d01cbb..d3cd2a94d1e8 100644
--- a/fs/configfs/dir.c
+++ b/fs/configfs/dir.c
@@ -1780,8 +1780,8 @@ void configfs_unregister_group(struct config_group *group)
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);
@@ -1922,10 +1922,10 @@ void configfs_unregister_subsystem(struct configfs_subsystem *subsys)
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));
diff --git a/fs/devpts/inode.c b/fs/devpts/inode.c
index 42e5a766d33c..4f25015aa534 100644
--- a/fs/devpts/inode.c
+++ b/fs/devpts/inode.c
@@ -621,8 +621,8 @@ void devpts_pty_kill(struct dentry *dentry)
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() */
}
diff --git a/fs/nfsd/nfsctl.c b/fs/nfsd/nfsctl.c
index b9f27fbcd768..68b020f2002b 100644
--- a/fs/nfsd/nfsctl.c
+++ b/fs/nfsd/nfsctl.c
@@ -1247,7 +1247,8 @@ static void nfsdfs_remove_file(struct inode *dir, struct dentry *dentry)
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);
}
@@ -1338,8 +1339,8 @@ void nfsd_client_rmdir(struct dentry *dentry)
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);
}
diff --git a/net/sunrpc/rpc_pipe.c b/net/sunrpc/rpc_pipe.c
index ee5336d73fdd..35588f0afa86 100644
--- a/net/sunrpc/rpc_pipe.c
+++ b/net/sunrpc/rpc_pipe.c
@@ -600,9 +600,9 @@ static int __rpc_rmdir(struct inode *dir, struct dentry *dentry)
dget(dentry);
ret = simple_rmdir(dir, dentry);
+ d_drop(dentry);
if (!ret)
fsnotify_rmdir(dir, dentry);
- d_delete(dentry);
dput(dentry);
return ret;
}
@@ -613,9 +613,9 @@ static int __rpc_unlink(struct inode *dir, struct dentry *dentry)
dget(dentry);
ret = simple_unlink(dir, dentry);
+ d_drop(dentry);
if (!ret)
fsnotify_unlink(dir, dentry);
- d_delete(dentry);
dput(dentry);
return ret;
}