[v2] tracefs: Have new files inherit the ownership of their parent

Commit Message

Steven Rostedt Dec. 8, 2021, 12:57 p.m. UTC

From: "Steven Rostedt (VMware)" <[e-mail]>

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.

Cc: Kees Cook <[e-mail]>
Cc: Ingo Molnar <[e-mail]>
Cc: Andrew Morton <[e-mail]>
Cc: Linus Torvalds <[e-mail]>
Cc: Al Viro <[e-mail]>
Cc: Greg Kroah-Hartman <[e-mail]>
Cc: Yabin Cui <[e-mail]>
Cc: Christian Brauner <[e-mail]>
Cc: [e-mail]
Fixes: 4282d60689d4f ("tracefs: Add new tracefs file system")
Reported-by: Kalesh Singh <[e-mail]>
Reported: https://lore.kernel.org/all/CAC_TJve8MMAv+H_NdLSJXZUSoxOEq2zB_pVaJ9p=[e-mail]/
Signed-off-by: Steven Rostedt (VMware) <[e-mail]>
---
Changes since v1: https://lkml.kernel.org/r/[e-mail]
  - Use d_inode() helper function as suggested by Christian.

 fs/tracefs/inode.c | 4 ++++
 1 file changed, 4 insertions(+)

Patch

diff --git a/fs/tracefs/inode.c b/fs/tracefs/inode.c
index 925a621b432e..06cf0534cc60 100644
--- a/fs/tracefs/inode.c
+++ b/fs/tracefs/inode.c
@@ -414,6 +414,8 @@  struct dentry *tracefs_create_file(const char *name, umode_t mode,
 	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);
@@ -436,6 +438,8 @@  static struct dentry *__create_dir(const char *name, struct dentry *parent,
 	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);