1 files changed, 173 insertions, 0 deletions

diff --git a/fs/efivarfs/inode.c b/fs/efivarfs/inode.c
new file mode 100644
index 000000000000..640e289d522e
--- /dev/null
+++ b/fs/efivarfs/inode.c
@@ -0,0 +1,173 @@
+/*
+ * 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 "internal.h"
+
+struct inode *efivarfs_get_inode(struct super_block *sb,
+                                const struct inode *dir, int mode, dev_t dev)
+{
+        struct inode *inode = new_inode(sb);
+
+        if (inode) {
+                inode->i_ino = get_next_ino();
+                inode->i_mode = mode;
+                inode->i_atime = inode->i_mtime = inode->i_ctime = CURRENT_TIME;
+                switch (mode & S_IFMT) {
+                case S_IFREG:
+                        inode->i_fop = &efivarfs_file_operations;
+                        break;
+                case S_IFDIR:
+                        inode->i_op = &efivarfs_dir_inode_operations;
+                        inode->i_fop = &simple_dir_operations;
+                        inc_nlink(inode);
+                        break;
+                }
+        }
+        return inode;
+}
+
+/*
+ * Return true if 'str' is a valid efivarfs filename of the form,
+ *
+ *      VariableName-12345678-1234-1234-1234-1234567891bc
+ */
+bool efivarfs_valid_name(const char *str, int len)
+{
+        static const char dashes[EFI_VARIABLE_GUID_LEN] = {
+                [8] = 1, [13] = 1, [18] = 1, [23] = 1
+        };
+        const char *s = str + len - EFI_VARIABLE_GUID_LEN;
+        int i;
+
+        /*
+         * We need a GUID, plus at least one letter for the variable name,
+         * plus the '-' separator
+         */
+        if (len < EFI_VARIABLE_GUID_LEN + 2)
+                return false;
+
+        /* GUID must be preceded by a '-' */
+        if (*(s - 1) != '-')
+                return false;
+
+        /*
+         * Validate that 's' is of the correct format, e.g.
+         *
+         *      12345678-1234-1234-1234-123456789abc
+         */
+        for (i = 0; i < EFI_VARIABLE_GUID_LEN; i++) {
+                if (dashes[i]) {
+                        if (*s++ != '-')
+                                return false;
+                } else {
+                        if (!isxdigit(*s++))
+                                return false;
+                }
+        }
+
+        return true;
+}
+
+static void efivarfs_hex_to_guid(const char *str, efi_guid_t *guid)
+{
+        guid->b[0] = hex_to_bin(str[6]) << 4 | hex_to_bin(str[7]);
+        guid->b[1] = hex_to_bin(str[4]) << 4 | hex_to_bin(str[5]);
+        guid->b[2] = hex_to_bin(str[2]) << 4 | hex_to_bin(str[3]);
+        guid->b[3] = hex_to_bin(str[0]) << 4 | hex_to_bin(str[1]);
+        guid->b[4] = hex_to_bin(str[11]) << 4 | hex_to_bin(str[12]);
+        guid->b[5] = hex_to_bin(str[9]) << 4 | hex_to_bin(str[10]);
+        guid->b[6] = hex_to_bin(str[16]) << 4 | hex_to_bin(str[17]);
+        guid->b[7] = hex_to_bin(str[14]) << 4 | hex_to_bin(str[15]);
+        guid->b[8] = hex_to_bin(str[19]) << 4 | hex_to_bin(str[20]);
+        guid->b[9] = hex_to_bin(str[21]) << 4 | hex_to_bin(str[22]);
+        guid->b[10] = hex_to_bin(str[24]) << 4 | hex_to_bin(str[25]);
+        guid->b[11] = hex_to_bin(str[26]) << 4 | hex_to_bin(str[27]);
+        guid->b[12] = hex_to_bin(str[28]) << 4 | hex_to_bin(str[29]);
+        guid->b[13] = hex_to_bin(str[30]) << 4 | hex_to_bin(str[31]);
+        guid->b[14] = hex_to_bin(str[32]) << 4 | hex_to_bin(str[33]);
+        guid->b[15] = hex_to_bin(str[34]) << 4 | hex_to_bin(str[35]);
+}
+
+static int efivarfs_create(struct inode *dir, struct dentry *dentry,
+                          umode_t mode, bool excl)
+{
+        struct inode *inode;
+        struct efivar_entry *var;
+        int namelen, i = 0, err = 0;
+
+        if (!efivarfs_valid_name(dentry->d_name.name, dentry->d_name.len))
+                return -EINVAL;
+
+        inode = efivarfs_get_inode(dir->i_sb, dir, mode, 0);
+        if (!inode)
+                return -ENOMEM;
+
+        var = kzalloc(sizeof(struct efivar_entry), GFP_KERNEL);
+        if (!var) {
+                err = -ENOMEM;
+                goto out;
+        }
+
+        /* length of the variable name itself: remove GUID and separator */
+        namelen = dentry->d_name.len - EFI_VARIABLE_GUID_LEN - 1;
+
+        efivarfs_hex_to_guid(dentry->d_name.name + namelen + 1,
+                        &var->var.VendorGuid);
+
+        for (i = 0; i < namelen; i++)
+                var->var.VariableName[i] = dentry->d_name.name[i];
+
+        var->var.VariableName[i] = '\0';
+
+        inode->i_private = var;
+
+        efivar_entry_add(var, &efivarfs_list);
+        d_instantiate(dentry, inode);
+        dget(dentry);
+out:
+        if (err) {
+                kfree(var);
+                iput(inode);
+        }
+        return err;
+}
+
+static int efivarfs_unlink(struct inode *dir, struct dentry *dentry)
+{
+        struct efivar_entry *var = dentry->d_inode->i_private;
+
+        if (efivar_entry_delete(var))
+                return -EINVAL;
+
+        drop_nlink(dentry->d_inode);
+        dput(dentry);
+        return 0;
+};
+
+/*
+ * Handle negative dentry.
+ */
+static struct dentry *efivarfs_lookup(struct inode *dir, struct dentry *dentry,
+                                      unsigned int flags)
+{
+        if (dentry->d_name.len > NAME_MAX)
+                return ERR_PTR(-ENAMETOOLONG);
+        d_add(dentry, NULL);
+        return NULL;
+}
+
+const struct inode_operations efivarfs_dir_inode_operations = {
+        .lookup = efivarfs_lookup,
+        .unlink = efivarfs_unlink,
+        .create = efivarfs_create,
+};