From fa6fe07d1536361a227d655e69ca270faf28fdbe Mon Sep 17 00:00:00 2001 From: NeilBrown Date: Wed, 19 Mar 2025 14:01:35 +1100 Subject: VFS: rename lookup_one_len family to lookup_noperm and remove permission check The lookup_one_len family of functions is (now) only used internally by a filesystem on itself either - in a context where permission checking is irrelevant such as by a virtual filesystem populating itself, or xfs accessing its ORPHANAGE or dquota accessing the quota file; or - in a context where a permission check (MAY_EXEC on the parent) has just been performed such as a network filesystem finding in "silly-rename" file in the same directory. This is also the context after the _parentat() functions where currently lookup_one_qstr_excl() is used. So the permission check is pointless. The name "one_len" is unhelpful in understanding the purpose of these functions and should be changed. Most of the callers pass the len as "strlen()" so using a qstr and QSTR() can simplify the code. This patch renames these functions (include lookup_positive_unlocked() which is part of the family despite the name) to have a name based on "lookup_noperm". They are changed to receive a 'struct qstr' instead of separate name and len. In a few cases the use of QSTR() results in a new call to strlen(). try_lookup_noperm() takes a pointer to a qstr instead of the whole qstr. This is consistent with d_hash_and_lookup() (which is nearly identical) and useful for lookup_noperm_unlocked(). The new lookup_noperm_common() doesn't take a qstr yet. That will be tidied up in a subsequent patch. Signed-off-by: NeilBrown Link: https://lore.kernel.org/r/20250319031545.2999807-5-neil@brown.name Signed-off-by: Christian Brauner --- ipc/mqueue.c | 5 ++--- 1 file changed, 2 insertions(+), 3 deletions(-) (limited to 'ipc') diff --git a/ipc/mqueue.c b/ipc/mqueue.c index 35b4f8659904..82ed2d3c9846 100644 --- a/ipc/mqueue.c +++ b/ipc/mqueue.c @@ -913,7 +913,7 @@ static int do_mq_open(const char __user *u_name, int oflag, umode_t mode, ro = mnt_want_write(mnt); /* we'll drop it in any case */ inode_lock(d_inode(root)); - path.dentry = lookup_one_len(name->name, root, strlen(name->name)); + path.dentry = lookup_noperm(&QSTR(name->name), root); if (IS_ERR(path.dentry)) { error = PTR_ERR(path.dentry); goto out_putfd; @@ -969,8 +969,7 @@ SYSCALL_DEFINE1(mq_unlink, const char __user *, u_name) if (err) goto out_name; inode_lock_nested(d_inode(mnt->mnt_root), I_MUTEX_PARENT); - dentry = lookup_one_len(name->name, mnt->mnt_root, - strlen(name->name)); + dentry = lookup_noperm(&QSTR(name->name), mnt->mnt_root); if (IS_ERR(dentry)) { err = PTR_ERR(dentry); goto out_unlock; -- cgit v1.2.3