From cf71eaa1ad18d6f6e130cda708300b587176f16f Mon Sep 17 00:00:00 2001 From: Christian Brauner Date: Tue, 6 Aug 2024 18:02:32 +0200 Subject: [PATCH] proc: block mounting on top of /proc//fdinfo/* Entries under /proc//fdinfo/* 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-v1-6-fb04e1d09f0c@kernel.org Reviewed-by: Josef Bacik Signed-off-by: Christian Brauner --- fs/proc/fd.c | 4 ++-- 1 file changed, 2 insertions(+), 2 deletions(-) diff --git a/fs/proc/fd.c b/fs/proc/fd.c index 671a45884304..623780449c48 100644 --- a/fs/proc/fd.c +++ b/fs/proc/fd.c @@ -397,8 +397,8 @@ static struct dentry *proc_fdinfo_instantiate(struct dentry *dentry, inode->i_fop = &proc_fdinfo_file_operations; tid_fd_update_inode(task, inode, 0); - 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 * -- 2.34.1