Unverified Commit b816dd5d authored by Christian Brauner's avatar Christian Brauner
Browse files

init: handle idmapped mounts 

Enable the init helpers to handle idmapped mounts by passing down the
mount's user namespace. If the initial user namespace is passed nothing
changes so non-idmapped mounts will see identical behavior as before.

Link: https://lore.kernel.org/r/20210121131959.646623-21-christian.brauner@ubuntu.com


Cc: Christoph Hellwig <hch@lst.de>
Cc: David Howells <dhowells@redhat.com>
Cc: Al Viro <viro@zeniv.linux.org.uk>
Cc: linux-fsdevel@vger.kernel.org
Reviewed-by: default avatarChristoph Hellwig <hch@lst.de>
Signed-off-by: default avatarChristian Brauner <christian.brauner@ubuntu.com>
parent 9eccd12c

fs/init.c

+11 −9
Original line number Diff line number Diff line
@@ -157,8 +157,8 @@ int __init init_mknod(const char *filename, umode_t mode, unsigned int dev) 
		mode &= ~current_umask();

	error = security_path_mknod(&path, dentry, mode, dev);

	if (!error)

		error = vfs_mknod(&init_user_ns, path.dentry->d_inode, dentry,

				  mode, new_decode_dev(dev));

		error = vfs_mknod(mnt_user_ns(path.mnt), path.dentry->d_inode,

				  dentry, mode, new_decode_dev(dev));

	done_path_create(&path, dentry);

	return error;

}
@@ -167,6 +167,7 @@ int __init init_link(const char *oldname, const char *newname) 
{

	struct dentry *new_dentry;

	struct path old_path, new_path;

	struct user_namespace *mnt_userns;

	int error;



	error = kern_path(oldname, 0, &old_path);
@@ -181,14 +182,15 @@ int __init init_link(const char *oldname, const char *newname) 
	error = -EXDEV;

	if (old_path.mnt != new_path.mnt)

		goto out_dput;

	error = may_linkat(&init_user_ns, &old_path);

	mnt_userns = mnt_user_ns(new_path.mnt);

	error = may_linkat(mnt_userns, &old_path);

	if (unlikely(error))

		goto out_dput;

	error = security_path_link(old_path.dentry, &new_path, new_dentry);

	if (error)

		goto out_dput;

	error = vfs_link(old_path.dentry, &init_user_ns,

			 new_path.dentry->d_inode, new_dentry, NULL);

	error = vfs_link(old_path.dentry, mnt_userns, new_path.dentry->d_inode,

			 new_dentry, NULL);

out_dput:

	done_path_create(&new_path, new_dentry);

out:
@@ -207,8 +209,8 @@ int __init init_symlink(const char *oldname, const char *newname) 
		return PTR_ERR(dentry);

	error = security_path_symlink(&path, dentry, oldname);

	if (!error)

		error = vfs_symlink(&init_user_ns, path.dentry->d_inode, dentry,

				    oldname);

		error = vfs_symlink(mnt_user_ns(path.mnt), path.dentry->d_inode,

				    dentry, oldname);

	done_path_create(&path, dentry);

	return error;

}
@@ -231,8 +233,8 @@ int __init init_mkdir(const char *pathname, umode_t mode) 
		mode &= ~current_umask();

	error = security_path_mkdir(&path, dentry, mode);

	if (!error)

		error = vfs_mkdir(&init_user_ns, path.dentry->d_inode, dentry,

				  mode);

		error = vfs_mkdir(mnt_user_ns(path.mnt), path.dentry->d_inode,

				  dentry, mode);

	done_path_create(&path, dentry);

	return error;

}