From 3836b31c3e717fcaa2b63c69e4bcf8ff7b82e6e4 Mon Sep 17 00:00:00 2001 From: Christian Brauner Date: Tue, 6 Aug 2024 18:02:30 +0200 Subject: [PATCH] proc: block mounting on top of /proc//map_files/* Entries under /proc//map_files/* 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-v1-4-fb04e1d09f0c@kernel.org Reviewed-by: Josef Bacik Signed-off-by: Christian Brauner --- fs/proc/base.c | 4 ++-- 1 file changed, 2 insertions(+), 2 deletions(-) diff --git a/fs/proc/base.c b/fs/proc/base.c index 72a1acd03675c..fce3d377b8266 100644 --- a/fs/proc/base.c +++ b/fs/proc/base.c @@ -2276,8 +2276,8 @@ proc_map_files_instantiate(struct dentry *dentry, inode->i_op = &proc_map_files_link_inode_operations; inode->i_size = 64; - d_set_d_op(dentry, &tid_map_files_dentry_operations); - return d_splice_alias(inode, dentry); + return proc_splice_unmountable(inode, dentry, + &tid_map_files_dentry_operations); } static struct dentry *proc_map_files_lookup(struct inode *dir, -- 2.39.5