[PATCH v3 11/18] efivars: convert to fileattr

From: Miklos Szeredi
Date: Thu Mar 25 2021 - 15:39:16 EST


Use the fileattr API to let the VFS handle locking, permission checking and
conversion.

Signed-off-by: Miklos Szeredi <mszeredi@xxxxxxxxxx>
Cc: Matthew Garrett <mjg59@xxxxxxxxxxxxx>
---
fs/efivarfs/file.c | 77 ---------------------------------------------
fs/efivarfs/inode.c | 44 ++++++++++++++++++++++++++
2 files changed, 44 insertions(+), 77 deletions(-)

diff --git a/fs/efivarfs/file.c b/fs/efivarfs/file.c
index e6bc0302643b..d57ee15874f9 100644
--- a/fs/efivarfs/file.c
+++ b/fs/efivarfs/file.c
@@ -106,86 +106,9 @@ static ssize_t efivarfs_file_read(struct file *file, char __user *userbuf,
return size;
}

-static inline unsigned int efivarfs_getflags(struct inode *inode)
-{
- unsigned int i_flags;
- unsigned int flags = 0;
-
- i_flags = inode->i_flags;
- if (i_flags & S_IMMUTABLE)
- flags |= FS_IMMUTABLE_FL;
- return flags;
-}
-
-static int
-efivarfs_ioc_getxflags(struct file *file, void __user *arg)
-{
- struct inode *inode = file->f_mapping->host;
- unsigned int flags = efivarfs_getflags(inode);
-
- if (copy_to_user(arg, &flags, sizeof(flags)))
- return -EFAULT;
- return 0;
-}
-
-static int
-efivarfs_ioc_setxflags(struct file *file, void __user *arg)
-{
- struct inode *inode = file->f_mapping->host;
- unsigned int flags;
- unsigned int i_flags = 0;
- unsigned int oldflags = efivarfs_getflags(inode);
- int error;
-
- if (!inode_owner_or_capable(&init_user_ns, inode))
- return -EACCES;
-
- if (copy_from_user(&flags, arg, sizeof(flags)))
- return -EFAULT;
-
- if (flags & ~FS_IMMUTABLE_FL)
- return -EOPNOTSUPP;
-
- if (flags & FS_IMMUTABLE_FL)
- i_flags |= S_IMMUTABLE;
-
-
- error = mnt_want_write_file(file);
- if (error)
- return error;
-
- inode_lock(inode);
-
- error = vfs_ioc_setflags_prepare(inode, oldflags, flags);
- if (error)
- goto out;
-
- inode_set_flags(inode, i_flags, S_IMMUTABLE);
-out:
- inode_unlock(inode);
- mnt_drop_write_file(file);
- return error;
-}
-
-static long
-efivarfs_file_ioctl(struct file *file, unsigned int cmd, unsigned long p)
-{
- void __user *arg = (void __user *)p;
-
- switch (cmd) {
- case FS_IOC_GETFLAGS:
- return efivarfs_ioc_getxflags(file, arg);
- case FS_IOC_SETFLAGS:
- return efivarfs_ioc_setxflags(file, arg);
- }
-
- return -ENOTTY;
-}
-
const struct file_operations efivarfs_file_operations = {
.open = simple_open,
.read = efivarfs_file_read,
.write = efivarfs_file_write,
.llseek = no_llseek,
- .unlocked_ioctl = efivarfs_file_ioctl,
};
diff --git a/fs/efivarfs/inode.c b/fs/efivarfs/inode.c
index 14e2947975fd..939e5e242b98 100644
--- a/fs/efivarfs/inode.c
+++ b/fs/efivarfs/inode.c
@@ -10,9 +10,12 @@
#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)
@@ -26,6 +29,7 @@ struct inode *efivarfs_get_inode(struct super_block *sb,
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:
@@ -138,3 +142,43 @@ const struct inode_operations efivarfs_dir_inode_operations = {
.unlink = efivarfs_unlink,
.create = efivarfs_create,
};
+
+static int
+efivarfs_fileattr_get(struct dentry *dentry, struct fileattr *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 user_namespace *mnt_userns,
+ struct dentry *dentry, struct fileattr *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;
+}
+
+static const struct inode_operations efivarfs_file_inode_operations = {
+ .fileattr_get = efivarfs_fileattr_get,
+ .fileattr_set = efivarfs_fileattr_set,
+};
--
2.30.2