Unverified Commit 7b9d14af authored by Christian Brauner's avatar Christian Brauner
Browse files

fs: allow mount namespace fd 

We already allow a mount namespace id, enable mount namespace file
descriptors as well.

Link: https://lore.kernel.org/r/20240719-work-mount-namespace-v1-2-834113cab0d2@kernel.org


Reviewed-by: default avatarJosef Bacik <josef@toxicpanda.com>
Reviewed-by: default avatarJeff Layton <jlayton@kernel.org>
Signed-off-by: default avatarChristian Brauner <brauner@kernel.org>
parent 720261cf

fs/namespace.c

+32 −7
Original line number Diff line number Diff line
@@ -5243,12 +5243,37 @@ static int copy_mnt_id_req(const struct mnt_id_req __user *req, 
 * that, or if not simply grab a passive reference on our mount namespace and

 * return that.

 */

static struct mnt_namespace *grab_requested_mnt_ns(u64 mnt_ns_id)

static struct mnt_namespace *grab_requested_mnt_ns(const struct mnt_id_req *kreq)

{

	if (mnt_ns_id)

		return lookup_mnt_ns(mnt_ns_id);

	refcount_inc(&current->nsproxy->mnt_ns->passive);

	return current->nsproxy->mnt_ns;

	struct mnt_namespace *mnt_ns;



	if (kreq->mnt_ns_id && kreq->spare)

		return ERR_PTR(-EINVAL);



	if (kreq->mnt_ns_id)

		return lookup_mnt_ns(kreq->mnt_ns_id);



	if (kreq->spare) {

		struct ns_common *ns;



		CLASS(fd, f)(kreq->spare);

		if (!f.file)

			return ERR_PTR(-EBADF);



		if (!proc_ns_file(f.file))

			return ERR_PTR(-EINVAL);



		ns = get_proc_ns(file_inode(f.file));

		if (ns->ops->type != CLONE_NEWNS)

			return ERR_PTR(-EINVAL);



		mnt_ns = to_mnt_ns(ns);

	} else {

		mnt_ns = current->nsproxy->mnt_ns;

	}



	refcount_inc(&mnt_ns->passive);

	return mnt_ns;

}



SYSCALL_DEFINE4(statmount, const struct mnt_id_req __user *, req,
@@ -5269,7 +5294,7 @@ SYSCALL_DEFINE4(statmount, const struct mnt_id_req __user *, req, 
	if (ret)

		return ret;



	ns = grab_requested_mnt_ns(kreq.mnt_ns_id);

	ns = grab_requested_mnt_ns(&kreq);

	if (!ns)

		return -ENOENT;
@@ -5396,7 +5421,7 @@ SYSCALL_DEFINE4(listmount, const struct mnt_id_req __user *, req, 
	if (!kmnt_ids)

		return -ENOMEM;



	ns = grab_requested_mnt_ns(kreq.mnt_ns_id);

	ns = grab_requested_mnt_ns(&kreq);

	if (!ns)

		return -ENOENT;