1 files changed, 108 insertions, 0 deletions

diff --git a/security/integrity/evm/evm_secfs.c b/security/integrity/evm/evm_secfs.c
new file mode 100644
index 000000000000..ac7629950578
--- /dev/null
+++ b/security/integrity/evm/evm_secfs.c
@@ -0,0 +1,108 @@
+/*
+ * Copyright (C) 2010 IBM Corporation
+ *
+ * Authors:
+ * Mimi Zohar <zohar@us.ibm.com>
+ *
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation, version 2 of the License.
+ *
+ * File: evm_secfs.c
+ *      - Used to signal when key is on keyring
+ *      - Get the key and enable EVM
+ */
+
+#include <linux/uaccess.h>
+#include <linux/module.h>
+#include "evm.h"
+
+static struct dentry *evm_init_tpm;
+
+/**
+ * evm_read_key - read() for <securityfs>/evm
+ *
+ * @filp: file pointer, not actually used
+ * @buf: where to put the result
+ * @count: maximum to send along
+ * @ppos: where to start
+ *
+ * Returns number of bytes read or error code, as appropriate
+ */
+static ssize_t evm_read_key(struct file *filp, char __user *buf,
+                            size_t count, loff_t *ppos)
+{
+        char temp[80];
+        ssize_t rc;
+
+        if (*ppos != 0)
+                return 0;
+
+        sprintf(temp, "%d", evm_initialized);
+        rc = simple_read_from_buffer(buf, count, ppos, temp, strlen(temp));
+
+        return rc;
+}
+
+/**
+ * evm_write_key - write() for <securityfs>/evm
+ * @file: file pointer, not actually used
+ * @buf: where to get the data from
+ * @count: bytes sent
+ * @ppos: where to start
+ *
+ * Used to signal that key is on the kernel key ring.
+ * - get the integrity hmac key from the kernel key ring
+ * - create list of hmac protected extended attributes
+ * Returns number of bytes written or error code, as appropriate
+ */
+static ssize_t evm_write_key(struct file *file, const char __user *buf,
+                             size_t count, loff_t *ppos)
+{
+        char temp[80];
+        int i, error;
+
+        if (!capable(CAP_SYS_ADMIN) || evm_initialized)
+                return -EPERM;
+
+        if (count >= sizeof(temp) || count == 0)
+                return -EINVAL;
+
+        if (copy_from_user(temp, buf, count) != 0)
+                return -EFAULT;
+
+        temp[count] = '\0';
+
+        if ((sscanf(temp, "%d", &i) != 1) || (i != 1))
+                return -EINVAL;
+
+        error = evm_init_key();
+        if (!error) {
+                evm_initialized = 1;
+                pr_info("EVM: initialized\n");
+        } else
+                pr_err("EVM: initialization failed\n");
+        return count;
+}
+
+static const struct file_operations evm_key_ops = {
+        .read           = evm_read_key,
+        .write          = evm_write_key,
+};
+
+int __init evm_init_secfs(void)
+{
+        int error = 0;
+
+        evm_init_tpm = securityfs_create_file("evm", S_IRUSR | S_IRGRP,
+                                              NULL, NULL, &evm_key_ops);
+        if (!evm_init_tpm || IS_ERR(evm_init_tpm))
+                error = -EFAULT;
+        return error;
+}
+
+void __exit evm_cleanup_secfs(void)
+{
+        if (evm_init_tpm)
+                securityfs_remove(evm_init_tpm);
+}