From 74ce208089f468db26eddcc5ea58e50f5bbbc291 Mon Sep 17 00:00:00 2001 From: Christian Brauner Date: Tue, 6 Aug 2024 18:02:31 +0200 Subject: proc: block mounting on top of /proc//fd/* Entries under /proc//fd/* are ephemeral and may go away before the process dies. As such allowing them to be used as mount points creates the ability to leak mounts that linger until the process dies with no ability to unmount them until then. Don't allow using them as mountpoints. Link: https://lore.kernel.org/r/20240806-work-procfs-v1-5-fb04e1d09f0c@kernel.org Reviewed-by: Josef Bacik Signed-off-by: Christian Brauner --- fs/proc/fd.c | 4 ++-- 1 file changed, 2 insertions(+), 2 deletions(-) (limited to 'fs/proc') diff --git a/fs/proc/fd.c b/fs/proc/fd.c index 105d6ce5b268..671a45884304 100644 --- a/fs/proc/fd.c +++ b/fs/proc/fd.c @@ -220,8 +220,8 @@ static struct dentry *proc_fd_instantiate(struct dentry *dentry, ei->op.proc_get_link = proc_fd_link; tid_fd_update_inode(task, inode, data->mode); - d_set_d_op(dentry, &tid_fd_dentry_operations); - return d_splice_alias(inode, dentry); + return proc_splice_unmountable(inode, dentry, + &tid_fd_dentry_operations); } static struct dentry *proc_lookupfd_common(struct inode *dir, -- cgit v1.2.3-70-g09d2