partially fix up the lookup_one_noperm mess
Try to fix the mess created by sysfs braindamage.
- refactor code internal to fs/namei.c a little to avoid too much
duplication:
o __lookup_hash_kern is renamed back to __lookup_hash
o the old __lookup_hash goes away, permission checks moves to
the two callers
o useless inline qualifiers on above functions go away
- lookup_one_len_kern loses it's last argument and is renamed to
lookup_one_noperm to make it's useage a little more clear
- added kerneldoc comments to describe lookup_one_len aswell as
lookup_one_noperm and make it very clear that no one should use
the latter ever.
Signed-off-by: Christoph Hellwig <hch@lst.de>
Cc: Josef 'Jeff' Sipek <jsipek@cs.sunysb.edu>
Cc: Miklos Szeredi <miklos@szeredi.hu>
Cc: Al Viro <viro@zeniv.linux.org.uk>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
diff --git a/fs/namei.c b/fs/namei.c
index b40b8084..bab0d19 100644
--- a/fs/namei.c
+++ b/fs/namei.c
@@ -1273,7 +1273,8 @@
return err;
}
-static inline struct dentry *__lookup_hash_kern(struct qstr *name, struct dentry *base, struct nameidata *nd)
+static struct dentry *__lookup_hash(struct qstr *name,
+ struct dentry *base, struct nameidata *nd)
{
struct dentry *dentry;
struct inode *inode;
@@ -1313,31 +1314,18 @@
* needs parent already locked. Doesn't follow mounts.
* SMP-safe.
*/
-static inline struct dentry * __lookup_hash(struct qstr *name, struct dentry *base, struct nameidata *nd)
-{
- struct dentry *dentry;
- struct inode *inode;
- int err;
-
- inode = base->d_inode;
-
- err = permission(inode, MAY_EXEC, nd);
- dentry = ERR_PTR(err);
- if (err)
- goto out;
-
- dentry = __lookup_hash_kern(name, base, nd);
-out:
- return dentry;
-}
-
static struct dentry *lookup_hash(struct nameidata *nd)
{
+ int err;
+
+ err = permission(nd->dentry->d_inode, MAY_EXEC, nd);
+ if (err)
+ return ERR_PTR(err);
return __lookup_hash(&nd->last, nd->dentry, nd);
}
-/* SMP-safe */
-static inline int __lookup_one_len(const char *name, struct qstr *this, struct dentry *base, int len)
+static int __lookup_one_len(const char *name, struct qstr *this,
+ struct dentry *base, int len)
{
unsigned long hash;
unsigned int c;
@@ -1358,6 +1346,17 @@
return 0;
}
+/**
+ * lookup_one_len: filesystem helper to lookup single pathname component
+ * @name: pathname component to lookup
+ * @base: base directory to lookup from
+ * @len: maximum length @len should be interpreted to
+ *
+ * Note that this routine is purely a helper for filesystem useage and should
+ * not be called by generic code. Also note that by using this function to
+ * nameidata argument is passed to the filesystem methods and a filesystem
+ * using this helper needs to be prepared for that.
+ */
struct dentry *lookup_one_len(const char *name, struct dentry *base, int len)
{
int err;
@@ -1366,18 +1365,33 @@
err = __lookup_one_len(name, &this, base, len);
if (err)
return ERR_PTR(err);
+
+ err = permission(base->d_inode, MAY_EXEC, NULL);
+ if (err)
+ return ERR_PTR(err);
return __lookup_hash(&this, base, NULL);
}
-struct dentry *lookup_one_len_kern(const char *name, struct dentry *base, int len)
+/**
+ * lookup_one_noperm - bad hack for sysfs
+ * @name: pathname component to lookup
+ * @base: base directory to lookup from
+ *
+ * This is a variant of lookup_one_len that doesn't perform any permission
+ * checks. It's a horrible hack to work around the braindead sysfs
+ * architecture and should not be used anywhere else.
+ *
+ * DON'T USE THIS FUNCTION EVER, thanks.
+ */
+struct dentry *lookup_one_noperm(const char *name, struct dentry *base)
{
int err;
struct qstr this;
- err = __lookup_one_len(name, &this, base, len);
+ err = __lookup_one_len(name, &this, base, strlen(name));
if (err)
return ERR_PTR(err);
- return __lookup_hash_kern(&this, base, NULL);
+ return __lookup_hash(&this, base, NULL);
}
int fastcall __user_walk_fd(int dfd, const char __user *name, unsigned flags,