Unverified Commit d43dbf73 authored by Christian Brauner's avatar Christian Brauner
Browse files

mount: ensure we don't pointlessly walk the mount tree 

This logic got broken recently. Add it back.

Fixes: 474f7825 ("fs: add copy_mount_setattr() helper")
Link: https://lore.kernel.org/20250409-sektflaschen-gecko-27c021fbd222@brauner


Tested-by: default avatarMikhail Gavrilov <mikhail.v.gavrilov@gmail.com>
Signed-off-by: default avatarChristian Brauner <brauner@kernel.org>
parent b2b4483b

fs/namespace.c

+18 −12
Original line number Diff line number Diff line
@@ -5189,7 +5189,7 @@ static void finish_mount_kattr(struct mount_kattr *kattr) 
		mnt_idmap_put(kattr->mnt_idmap);

}



static int copy_mount_setattr(struct mount_attr __user *uattr, size_t usize,

static int wants_mount_setattr(struct mount_attr __user *uattr, size_t usize,

			       struct mount_kattr *kattr)

{

	int ret;
@@ -5213,9 +5213,13 @@ static int copy_mount_setattr(struct mount_attr __user *uattr, size_t usize, 
	if (attr.attr_set == 0 &&

	    attr.attr_clr == 0 &&

	    attr.propagation == 0)

		return 0;

		return 0; /* Tell caller to not bother. */



	return build_mount_kattr(&attr, usize, kattr);

	ret = build_mount_kattr(&attr, usize, kattr);

	if (ret < 0)

		return ret;



	return 1;

}



SYSCALL_DEFINE5(mount_setattr, int, dfd, const char __user *, path,
@@ -5247,8 +5251,8 @@ SYSCALL_DEFINE5(mount_setattr, int, dfd, const char __user *, path, 
	if (flags & AT_RECURSIVE)

		kattr.kflags |= MOUNT_KATTR_RECURSE;



	err = copy_mount_setattr(uattr, usize, &kattr);

	if (err)

	err = wants_mount_setattr(uattr, usize, &kattr);

	if (err <= 0)

		return err;



	err = user_path_at(dfd, path, kattr.lookup_flags, &target);
@@ -5282,16 +5286,18 @@ SYSCALL_DEFINE5(open_tree_attr, int, dfd, const char __user *, filename, 
		if (flags & AT_RECURSIVE)

			kattr.kflags |= MOUNT_KATTR_RECURSE;



		ret = copy_mount_setattr(uattr, usize, &kattr);

		if (ret)

		ret = wants_mount_setattr(uattr, usize, &kattr);

		if (ret < 0)

			return ret;



		if (ret) {

			ret = do_mount_setattr(&file->f_path, &kattr);

			if (ret)

				return ret;



			finish_mount_kattr(&kattr);

		}

	}



	fd = get_unused_fd_flags(flags & O_CLOEXEC);

	if (fd < 0)