[PATCH] sanitize __user_walk_fd() et.al.

* do not pass nameidata; struct path is all the callers want.
* switch to new helpers:
	user_path_at(dfd, pathname, flags, &path)
	user_path(pathname, &path)
	user_lpath(pathname, &path)
	user_path_dir(pathname, &path)  (fail if not a directory)
  The last 3 are trivial macro wrappers for the first one.
* remove nameidata in callers.

Signed-off-by: Al Viro <[email protected]>

arch/alpha/kernel/osf_sys.c

@@ -253,15 +253,15 @@ do_osf_statfs(struct dentry * dentry, struct osf_statfs __user *buffer,
 }
 
 asmlinkage int
-osf_statfs(char __user *path, struct osf_statfs __user *buffer, unsigned long bufsiz)
+osf_statfs(char __user *pathname, struct osf_statfs __user *buffer, unsigned long bufsiz)
 {
-	struct nameidata nd;
+	struct path path;
 	int retval;
 
-	retval = user_path_walk(path, &nd);
+	retval = user_path(pathname, &path);
 	if (!retval) {
-		retval = do_osf_statfs(nd.path.dentry, buffer, bufsiz);
-		path_put(&nd.path);
+		retval = do_osf_statfs(path.dentry, buffer, bufsiz);
+		path_put(&path);
 	}
 	return retval;
 }

arch/parisc/hpux/sys_hpux.c

@@ -210,19 +210,19 @@ static int vfs_statfs_hpux(struct dentry *dentry, struct hpux_statfs *buf)
 }
 
 /* hpux statfs */
-asmlinkage long hpux_statfs(const char __user *path,
+asmlinkage long hpux_statfs(const char __user *pathname,
 						struct hpux_statfs __user *buf)
 {
-	struct nameidata nd;
+	struct path path;
 	int error;
 
-	error = user_path_walk(path, &nd);
+	error = user_path(pathname, &path);
 	if (!error) {
 		struct hpux_statfs tmp;
-		error = vfs_statfs_hpux(nd.path.dentry, &tmp);
+		error = vfs_statfs_hpux(path.dentry, &tmp);
 		if (!error && copy_to_user(buf, &tmp, sizeof(tmp)))
 			error = -EFAULT;
-		path_put(&nd.path);
+		path_put(&path);
 	}
 	return error;
 }

fs/coda/pioctl.c

@@ -49,7 +49,7 @@ static int coda_ioctl_permission(struct inode *inode, int mask)
 static int coda_pioctl(struct inode * inode, struct file * filp, 
                        unsigned int cmd, unsigned long user_data)
 {
-	struct nameidata nd;
+	struct path path;
         int error;
 	struct PioctlData data;
         struct inode *target_inode = NULL;
@@ -64,21 +64,21 @@ static int coda_pioctl(struct inode * inode, struct file * filp,
          * Look up the pathname. Note that the pathname is in 
          * user memory, and namei takes care of this
          */
-        if ( data.follow ) {
-                error = user_path_walk(data.path, &nd);
+        if (data.follow) {
+                error = user_path(data.path, &path);
 	} else {
-	        error = user_path_walk_link(data.path, &nd);
+	        error = user_lpath(data.path, &path);
 	}
 
 	if ( error ) {
 		return error;
         } else {
-		target_inode = nd.path.dentry->d_inode;
+		target_inode = path.dentry->d_inode;
 	}
 
 	/* return if it is not a Coda inode */
 	if ( target_inode->i_sb != inode->i_sb ) {
-		path_put(&nd.path);
+		path_put(&path);
 	        return  -EINVAL;
 	}
 
@@ -87,7 +87,7 @@ static int coda_pioctl(struct inode * inode, struct file * filp,
 
 	error = venus_pioctl(inode->i_sb, &(cnp->c_fid), cmd, &data);
 
-	path_put(&nd.path);
+	path_put(&path);
         return error;
 }
 

fs/compat.c

@@ -234,18 +234,18 @@ static int put_compat_statfs(struct compat_statfs __user *ubuf, struct kstatfs *
  * The following statfs calls are copies of code from fs/open.c and
  * should be checked against those from time to time
  */
-asmlinkage long compat_sys_statfs(const char __user *path, struct compat_statfs __user *buf)
+asmlinkage long compat_sys_statfs(const char __user *pathname, struct compat_statfs __user *buf)
 {
-	struct nameidata nd;
+	struct path path;
 	int error;
 
-	error = user_path_walk(path, &nd);
+	error = user_path(pathname, &path);
 	if (!error) {
 		struct kstatfs tmp;
-		error = vfs_statfs(nd.path.dentry, &tmp);
+		error = vfs_statfs(path.dentry, &tmp);
 		if (!error)
 			error = put_compat_statfs(buf, &tmp);
-		path_put(&nd.path);
+		path_put(&path);
 	}
 	return error;
 }
@@ -299,21 +299,21 @@ static int put_compat_statfs64(struct compat_statfs64 __user *ubuf, struct kstat
 	return 0;
 }
 
-asmlinkage long compat_sys_statfs64(const char __user *path, compat_size_t sz, struct compat_statfs64 __user *buf)
+asmlinkage long compat_sys_statfs64(const char __user *pathname, compat_size_t sz, struct compat_statfs64 __user *buf)
 {
-	struct nameidata nd;
+	struct path path;
 	int error;
 
 	if (sz != sizeof(*buf))
 		return -EINVAL;
 
-	error = user_path_walk(path, &nd);
+	error = user_path(pathname, &path);
 	if (!error) {
 		struct kstatfs tmp;
-		error = vfs_statfs(nd.path.dentry, &tmp);
+		error = vfs_statfs(path.dentry, &tmp);
 		if (!error)
 			error = put_compat_statfs64(buf, &tmp);
-		path_put(&nd.path);
+		path_put(&path);
 	}
 	return error;
 }

fs/inotify_user.c

@@ -354,20 +354,20 @@ static void inotify_dev_event_dequeue(struct inotify_device *dev)
 }
 
 /*
- * find_inode - resolve a user-given path to a specific inode and return a nd
+ * find_inode - resolve a user-given path to a specific inode
  */
-static int find_inode(const char __user *dirname, struct nameidata *nd,
+static int find_inode(const char __user *dirname, struct path *path,
 		      unsigned flags)
 {
 	int error;
 
-	error = __user_walk(dirname, flags, nd);
+	error = user_path_at(AT_FDCWD, dirname, flags, path);
 	if (error)
 		return error;
 	/* you can only watch an inode if you have read permissions on it */
-	error = inode_permission(nd->path.dentry->d_inode, MAY_READ);
+	error = inode_permission(path->dentry->d_inode, MAY_READ);
 	if (error)
-		path_put(&nd->path);
+		path_put(path);
 	return error;
 }
 
@@ -650,11 +650,11 @@ asmlinkage long sys_inotify_init(void)
 	return sys_inotify_init1(0);
 }
 
-asmlinkage long sys_inotify_add_watch(int fd, const char __user *path, u32 mask)
+asmlinkage long sys_inotify_add_watch(int fd, const char __user *pathname, u32 mask)
 {
 	struct inode *inode;
 	struct inotify_device *dev;
-	struct nameidata nd;
+	struct path path;
 	struct file *filp;
 	int ret, fput_needed;
 	unsigned flags = 0;
@@ -674,12 +674,12 @@ asmlinkage long sys_inotify_add_watch(int fd, const char __user *path, u32 mask)
 	if (mask & IN_ONLYDIR)
 		flags |= LOOKUP_DIRECTORY;
 
-	ret = find_inode(path, &nd, flags);
+	ret = find_inode(pathname, &path, flags);
 	if (unlikely(ret))
 		goto fput_and_out;
 
-	/* inode held in place by reference to nd; dev by fget on fd */
-	inode = nd.path.dentry->d_inode;
+	/* inode held in place by reference to path; dev by fget on fd */
+	inode = path.dentry->d_inode;
 	dev = filp->private_data;
 
 	mutex_lock(&dev->up_mutex);
@@ -688,7 +688,7 @@ asmlinkage long sys_inotify_add_watch(int fd, const char __user *path, u32 mask)
 		ret = create_watch(dev, inode, mask);
 	mutex_unlock(&dev->up_mutex);
 
-	path_put(&nd.path);
+	path_put(&path);
 fput_and_out:
 	fput_light(filp, fput_needed);
 	return ret;

fs/namei.c

@@ -1334,24 +1334,24 @@ struct dentry *lookup_one_noperm(const char *name, struct dentry *base)
 	return __lookup_hash(&this, base, NULL);
 }
 
-int __user_walk_fd(int dfd, const char __user *name, unsigned flags,
-			    struct nameidata *nd)
+int user_path_at(int dfd, const char __user *name, unsigned flags,
+		 struct path *path)
 {
+	struct nameidata nd;
 	char *tmp = getname(name);
 	int err = PTR_ERR(tmp);
-
 	if (!IS_ERR(tmp)) {
-		err = do_path_lookup(dfd, tmp, flags, nd);
+
+		BUG_ON(flags & LOOKUP_PARENT);
+
+		err = do_path_lookup(dfd, tmp, flags, &nd);
 		putname(tmp);
+		if (!err)
+			*path = nd.path;
 	}
 	return err;
 }
 
-int __user_walk(const char __user *name, unsigned flags, struct nameidata *nd)
-{
-	return __user_walk_fd(AT_FDCWD, name, flags, nd);
-}
-
 /*
  * It's inline, so penalty for filesystems that don't use sticky bit is
  * minimal.
@@ -2446,7 +2446,8 @@ asmlinkage long sys_linkat(int olddfd, const char __user *oldname,
 			   int flags)
 {
 	struct dentry *new_dentry;
-	struct nameidata nd, old_nd;
+	struct nameidata nd;
+	struct path old_path;
 	int error;
 	char * to;
 
@@ -2457,16 +2458,16 @@ asmlinkage long sys_linkat(int olddfd, const char __user *oldname,
 	if (IS_ERR(to))
 		return PTR_ERR(to);
 
-	error = __user_walk_fd(olddfd, oldname,
-			       flags & AT_SYMLINK_FOLLOW ? LOOKUP_FOLLOW : 0,
-			       &old_nd);
+	error = user_path_at(olddfd, oldname,
+			     flags & AT_SYMLINK_FOLLOW ? LOOKUP_FOLLOW : 0,
+			     &old_path);
 	if (error)
 		goto exit;
 	error = do_path_lookup(newdfd, to, LOOKUP_PARENT, &nd);
 	if (error)
 		goto out;
 	error = -EXDEV;
-	if (old_nd.path.mnt != nd.path.mnt)
+	if (old_path.mnt != nd.path.mnt)
 		goto out_release;
 	new_dentry = lookup_create(&nd, 0);
 	error = PTR_ERR(new_dentry);
@@ -2475,7 +2476,7 @@ asmlinkage long sys_linkat(int olddfd, const char __user *oldname,
 	error = mnt_want_write(nd.path.mnt);
 	if (error)
 		goto out_dput;
-	error = vfs_link(old_nd.path.dentry, nd.path.dentry->d_inode, new_dentry);
+	error = vfs_link(old_path.dentry, nd.path.dentry->d_inode, new_dentry);
 	mnt_drop_write(nd.path.mnt);
 out_dput:
 	dput(new_dentry);
@@ -2484,7 +2485,7 @@ asmlinkage long sys_linkat(int olddfd, const char __user *oldname,
 out_release:
 	path_put(&nd.path);
 out:
-	path_put(&old_nd.path);
+	path_put(&old_path);
 exit:
 	putname(to);
 
@@ -2877,8 +2878,7 @@ const struct inode_operations page_symlink_inode_operations = {
 	.put_link	= page_put_link,
 };
 
-EXPORT_SYMBOL(__user_walk);
-EXPORT_SYMBOL(__user_walk_fd);
+EXPORT_SYMBOL(user_path_at);
 EXPORT_SYMBOL(follow_down);
 EXPORT_SYMBOL(follow_up);
 EXPORT_SYMBOL(get_write_access); /* binfmt_aout */