From 74d7970febf7e9005375aeda0df821d2edffc9f7 Mon Sep 17 00:00:00 2001 From: Namjae Jeon Date: Fri, 21 Apr 2023 16:09:01 +0900 Subject: ksmbd: fix racy issue from using ->d_parent and ->d_name Al pointed out that ksmbd has racy issue from using ->d_parent and ->d_name in ksmbd_vfs_unlink and smb2_vfs_rename(). and use new lock_rename_child() to lock stable parent while underlying rename racy. Introduce vfs_path_parent_lookup helper to avoid out of share access and export vfs functions like the following ones to use vfs_path_parent_lookup(). - rename __lookup_hash() to lookup_one_qstr_excl(). - export lookup_one_qstr_excl(). - export getname_kernel() and putname(). vfs_path_parent_lookup() is used for parent lookup of destination file using absolute pathname given from FILE_RENAME_INFORMATION request. Signed-off-by: Namjae Jeon Signed-off-by: Steve French --- include/linux/namei.h | 6 ++++++ 1 file changed, 6 insertions(+) (limited to 'include') diff --git a/include/linux/namei.h b/include/linux/namei.h index 5864e4d82e56..1463cbda4888 100644 --- a/include/linux/namei.h +++ b/include/linux/namei.h @@ -57,12 +57,18 @@ static inline int user_path_at(int dfd, const char __user *name, unsigned flags, return user_path_at_empty(dfd, name, flags, path, NULL); } +struct dentry *lookup_one_qstr_excl(const struct qstr *name, + struct dentry *base, + unsigned int flags); extern int kern_path(const char *, unsigned, struct path *); extern struct dentry *kern_path_create(int, const char *, struct path *, unsigned int); extern struct dentry *user_path_create(int, const char __user *, struct path *, unsigned int); extern void done_path_create(struct path *, struct dentry *); extern struct dentry *kern_path_locked(const char *, struct path *); +int vfs_path_parent_lookup(struct filename *filename, unsigned int flags, + struct path *parent, struct qstr *last, int *type, + const struct path *root); int vfs_path_lookup(struct dentry *, struct vfsmount *, const char *, unsigned int, struct path *); -- cgit v1.2.3