Commit f16ab99c authored by Linus Torvalds's avatar Linus Torvalds
Browse files

Merge tag 'pull-bcachefs-fix' of git://git.kernel.org/pub/scm/linux/kernel/git/viro/vfs 

Pull bcachefs locking fix from Al Viro:
 "Fix broken locking in bch2_ioctl_subvolume_destroy()"

* tag 'pull-bcachefs-fix' of git://git.kernel.org/pub/scm/linux/kernel/git/viro/vfs:
  bch2_ioctl_subvolume_destroy(): fix locking
  new helper: user_path_locked_at()
parents 1acc24b3 bbe6a7c8

fs/bcachefs/fs-ioctl.c

+17 −14
Original line number Diff line number Diff line
@@ -443,33 +443,36 @@ static long bch2_ioctl_subvolume_create(struct bch_fs *c, struct file *filp, 
static long bch2_ioctl_subvolume_destroy(struct bch_fs *c, struct file *filp,

				struct bch_ioctl_subvolume arg)

{

	const char __user *name = (void __user *)(unsigned long)arg.dst_ptr;

	struct path path;

	struct inode *dir;

	struct dentry *victim;

	int ret = 0;



	if (arg.flags)

		return -EINVAL;



	ret = user_path_at(arg.dirfd,

			(const char __user *)(unsigned long)arg.dst_ptr,

			LOOKUP_FOLLOW, &path);

	if (ret)

		return ret;

	victim = user_path_locked_at(arg.dirfd, name, &path);

	if (IS_ERR(victim))

		return PTR_ERR(victim);



	if (path.dentry->d_sb->s_fs_info != c) {

	if (victim->d_sb->s_fs_info != c) {

		ret = -EXDEV;

		goto err;

	}



	dir = path.dentry->d_parent->d_inode;



	ret = __bch2_unlink(dir, path.dentry, true);

	if (ret)

	if (!d_is_positive(victim)) {

		ret = -ENOENT;

		goto err;



	fsnotify_rmdir(dir, path.dentry);

	d_delete(path.dentry);

	}

	dir = d_inode(path.dentry);

	ret = __bch2_unlink(dir, victim, true);

	if (!ret) {

		fsnotify_rmdir(dir, victim);

		d_delete(victim);

	}

	inode_unlock(dir);

err:

	dput(victim);

	path_put(&path);

	return ret;

}

fs/namei.c

+13 −3
Original line number Diff line number Diff line
@@ -2572,13 +2572,13 @@ static int filename_parentat(int dfd, struct filename *name, 
}



/* does lookup, returns the object with parent locked */

static struct dentry *__kern_path_locked(struct filename *name, struct path *path)

static struct dentry *__kern_path_locked(int dfd, struct filename *name, struct path *path)

{

	struct dentry *d;

	struct qstr last;

	int type, error;



	error = filename_parentat(AT_FDCWD, name, 0, path, &last, &type);

	error = filename_parentat(dfd, name, 0, path, &last, &type);

	if (error)

		return ERR_PTR(error);

	if (unlikely(type != LAST_NORM)) {
@@ -2597,12 +2597,22 @@ static struct dentry *__kern_path_locked(struct filename *name, struct path *pat 
struct dentry *kern_path_locked(const char *name, struct path *path)

{

	struct filename *filename = getname_kernel(name);

	struct dentry *res = __kern_path_locked(filename, path);

	struct dentry *res = __kern_path_locked(AT_FDCWD, filename, path);



	putname(filename);

	return res;

}



struct dentry *user_path_locked_at(int dfd, const char __user *name, struct path *path)

{

	struct filename *filename = getname(name);

	struct dentry *res = __kern_path_locked(dfd, filename, path);



	putname(filename);

	return res;

}

EXPORT_SYMBOL(user_path_locked_at);



int kern_path(const char *name, unsigned int flags, struct path *path)

{

	struct filename *filename = getname_kernel(name);

include/linux/namei.h

+1 −0
Original line number Diff line number Diff line
@@ -66,6 +66,7 @@ extern struct dentry *kern_path_create(int, const char *, struct path *, unsigne 
extern struct dentry *user_path_create(int, const char __user *, struct path *, unsigned int);

extern void done_path_create(struct path *, struct dentry *);

extern struct dentry *kern_path_locked(const char *, struct path *);

extern struct dentry *user_path_locked_at(int , const char __user *, struct path *);

int vfs_path_parent_lookup(struct filename *filename, unsigned int flags,

			   struct path *parent, struct qstr *last, int *type,

			   const struct path *root);