1 files changed, 86 insertions, 35 deletions

diff --git a/fs/efivarfs/inode.c b/fs/efivarfs/inode.c
index 8c6ab6c95727..95dcad83da11 100644
--- a/fs/efivarfs/inode.c
+++ b/fs/efivarfs/inode.c
@@ -1,33 +1,39 @@
+// SPDX-License-Identifier: GPL-2.0-only
 /*
  * Copyright (C) 2012 Red Hat, Inc.
  * Copyright (C) 2012 Jeremy Kerr <jeremy.kerr@canonical.com>
- *
- * This program is free software; you can redistribute it and/or modify
- * it under the terms of the GNU General Public License version 2 as
- * published by the Free Software Foundation.
  */
 
 #include <linux/efi.h>
 #include <linux/fs.h>
 #include <linux/ctype.h>
+#include <linux/kmemleak.h>
 #include <linux/slab.h>
 #include <linux/uuid.h>
+#include <linux/fileattr.h>
 
 #include "internal.h"
 
+static const struct inode_operations efivarfs_file_inode_operations;
+
 struct inode *efivarfs_get_inode(struct super_block *sb,
 				const struct inode *dir, int mode,
 				dev_t dev, bool is_removable)
 {
 	struct inode *inode = new_inode(sb);
+	struct efivarfs_fs_info *fsi = sb->s_fs_info;
+	struct efivarfs_mount_opts *opts = &fsi->mount_opts;
 
 	if (inode) {
+		inode->i_uid = opts->uid;
+		inode->i_gid = opts->gid;
 		inode->i_ino = get_next_ino();
 		inode->i_mode = mode;
-		inode->i_atime = inode->i_mtime = inode->i_ctime = current_time(inode);
+		simple_inode_init_ts(inode);
 		inode->i_flags = is_removable ? 0 : S_IMMUTABLE;
 		switch (mode & S_IFMT) {
 		case S_IFREG:
+			inode->i_op = &efivarfs_file_inode_operations;
 			inode->i_fop = &efivarfs_file_operations;
 			break;
 		case S_IFDIR:
@@ -45,7 +51,7 @@ struct inode *efivarfs_get_inode(struct super_block *sb,
  *
  *	VariableName-12345678-1234-1234-1234-1234567891bc
  */
-bool efivarfs_valid_name(const char *str, int len)
+static bool efivarfs_valid_name(const char *str, int len)
 {
 	const char *s = str + len - EFI_VARIABLE_GUID_LEN;
 
@@ -68,37 +74,37 @@ bool efivarfs_valid_name(const char *str, int len)
 	return uuid_is_valid(s);
 }
 
-static int efivarfs_create(struct inode *dir, struct dentry *dentry,
-			  umode_t mode, bool excl)
+static int efivarfs_create(struct mnt_idmap *idmap, struct inode *dir,
+			   struct dentry *dentry, umode_t mode, bool excl)
 {
 	struct inode *inode = NULL;
 	struct efivar_entry *var;
 	int namelen, i = 0, err = 0;
 	bool is_removable = false;
+	efi_guid_t vendor;
 
 	if (!efivarfs_valid_name(dentry->d_name.name, dentry->d_name.len))
 		return -EINVAL;
 
-	var = kzalloc(sizeof(struct efivar_entry), GFP_KERNEL);
-	if (!var)
-		return -ENOMEM;
-
 	/* length of the variable name itself: remove GUID and separator */
 	namelen = dentry->d_name.len - EFI_VARIABLE_GUID_LEN - 1;
 
-	err = guid_parse(dentry->d_name.name + namelen + 1, &var->var.VendorGuid);
+	err = guid_parse(dentry->d_name.name + namelen + 1, &vendor);
 	if (err)
-		goto out;
+		return err;
+	if (guid_equal(&vendor, &LINUX_EFI_RANDOM_SEED_TABLE_GUID))
+		return -EPERM;
 
-	if (efivar_variable_is_removable(var->var.VendorGuid,
+	if (efivar_variable_is_removable(vendor,
 					 dentry->d_name.name, namelen))
 		is_removable = true;
 
 	inode = efivarfs_get_inode(dir->i_sb, dir, mode, 0, is_removable);
-	if (!inode) {
-		err = -ENOMEM;
-		goto out;
-	}
+	if (!inode)
+		return -ENOMEM;
+	var = efivar_entry(inode);
+
+	var->var.VendorGuid = vendor;
 
 	for (i = 0; i < namelen; i++)
 		var->var.VariableName[i] = dentry->d_name.name[i];
@@ -107,19 +113,9 @@ static int efivarfs_create(struct inode *dir, struct dentry *dentry,
 
 	inode->i_private = var;
 
-	err = efivar_entry_add(var, &efivarfs_list);
-	if (err)
-		goto out;
-
-	d_instantiate(dentry, inode);
-	dget(dentry);
-out:
-	if (err) {
-		kfree(var);
-		if (inode)
-			iput(inode);
-	}
-	return err;
+	d_make_persistent(dentry, inode);
+
+	return 0;
 }
 
 static int efivarfs_unlink(struct inode *dir, struct dentry *dentry)
@@ -129,9 +125,7 @@ static int efivarfs_unlink(struct inode *dir, struct dentry *dentry)
 	if (efivar_entry_delete(var))
 		return -EINVAL;
 
-	drop_nlink(d_inode(dentry));
-	dput(dentry);
-	return 0;
+	return simple_unlink(dir, dentry);
 };
 
 const struct inode_operations efivarfs_dir_inode_operations = {
@@ -139,3 +133,60 @@ const struct inode_operations efivarfs_dir_inode_operations = {
 	.unlink = efivarfs_unlink,
 	.create = efivarfs_create,
 };
+
+static int
+efivarfs_fileattr_get(struct dentry *dentry, struct file_kattr *fa)
+{
+	unsigned int i_flags;
+	unsigned int flags = 0;
+
+	i_flags = d_inode(dentry)->i_flags;
+	if (i_flags & S_IMMUTABLE)
+		flags |= FS_IMMUTABLE_FL;
+
+	fileattr_fill_flags(fa, flags);
+
+	return 0;
+}
+
+static int
+efivarfs_fileattr_set(struct mnt_idmap *idmap,
+		      struct dentry *dentry, struct file_kattr *fa)
+{
+	unsigned int i_flags = 0;
+
+	if (fileattr_has_fsx(fa))
+		return -EOPNOTSUPP;
+
+	if (fa->flags & ~FS_IMMUTABLE_FL)
+		return -EOPNOTSUPP;
+
+	if (fa->flags & FS_IMMUTABLE_FL)
+		i_flags |= S_IMMUTABLE;
+
+	inode_set_flags(d_inode(dentry), i_flags, S_IMMUTABLE);
+
+	return 0;
+}
+
+/* copy of simple_setattr except that it doesn't do i_size updates */
+static int efivarfs_setattr(struct mnt_idmap *idmap, struct dentry *dentry,
+		   struct iattr *iattr)
+{
+	struct inode *inode = d_inode(dentry);
+	int error;
+
+	error = setattr_prepare(idmap, dentry, iattr);
+	if (error)
+		return error;
+
+	setattr_copy(idmap, inode, iattr);
+	mark_inode_dirty(inode);
+	return 0;
+}
+
+static const struct inode_operations efivarfs_file_inode_operations = {
+	.fileattr_get = efivarfs_fileattr_get,
+	.fileattr_set = efivarfs_fileattr_set,
+	.setattr      = efivarfs_setattr,
+};