[PATCH 5.10 057/132] tracefs: Have new files inherit the ownership of their parent

Greg Kroah-Hartman
2021-12-13T10:17:52Z

From: Steven Rostedt (VMware) <rostedt@goodmis.org>

commit ee7f3666995d8537dec17b1d35425f28877671a9 upstream.

If directories in tracefs have their ownership changed, then any new files
and directories that are created under those directories should inherit
the ownership of the director they are created in.

Link: https://lkml.kernel.org/r/20211208075720.4855d180@gandalf.local.home

Cc: Kees Cook <keescook@chromium.org>
Cc: Ingo Molnar <mingo@kernel.org>
Cc: Andrew Morton <akpm@linux-foundation.org>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Al Viro <viro@zeniv.linux.org.uk>
Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Cc: Yabin Cui <yabinc@google.com>
Cc: Christian Brauner <christian.brauner@ubuntu.com>
Cc: stable@vger.kernel.org
Fixes: 4282d60689d4f ("tracefs: Add new tracefs file system")
Reported-by: Kalesh Singh <kaleshsingh@google.com>
Reported: https://lore.kernel.org/all/CAC_TJve8MMAv+H_NdLSJXZUSoxOEq2zB_pVaJ9p=7H6Bu3X76g@mail.gmail.com/
Signed-off-by: Steven Rostedt (VMware) <rostedt@goodmis.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
---
fs/tracefs/inode.c | 4 ++++
1 file changed, 4 insertions(+)

--- a/fs/tracefs/inode.c
+++ b/fs/tracefs/inode.c
@@ -412,6 +412,8 @@ struct dentry *tracefs_create_file(const
inode->i_mode = mode;
inode->i_fop = fops ? fops : &tracefs_file_operations;
inode->i_private = data;
+ inode->i_uid = d_inode(dentry->d_parent)->i_uid;
+ inode->i_gid = d_inode(dentry->d_parent)->i_gid;
d_instantiate(dentry, inode);
fsnotify_create(dentry->d_parent->d_inode, dentry);
return end_creating(dentry);
@@ -434,6 +436,8 @@ static struct dentry *__create_dir(const
inode->i_mode = S_IFDIR | S_IRWXU | S_IRUSR| S_IRGRP | S_IXUSR | S_IXGRP;
inode->i_op = ops;
inode->i_fop = &simple_dir_operations;
+ inode->i_uid = d_inode(dentry->d_parent)->i_uid;
+ inode->i_gid = d_inode(dentry->d_parent)->i_gid;

/* directory inodes start off with i_nlink == 2 (for "." entry) */
inc_nlink(inode);