ecryptfs: enhancing ecryptfs to be configurable with encryption type

enabled eCryptfs for qcom targets. In addition to the usual
options, a special mode 'aes-xts' was added for qcom ICE hw
encryption

Change-Id: I20c01adc46c977b4a5db0be9ff93384cda14bc56
Signed-off-by: Lina Zarivach <linaz@codeaurora.org>
Signed-off-by: Andrey Markovytch <andreym@codeaurora.org>
[gbroner@codeaurora.org: fix merge conflict]
Signed-off-by: Gilad Broner <gbroner@codeaurora.org>

1 files changed, 212 insertions, 0 deletions

diff --git a/fs/ecryptfs/events.c b/fs/ecryptfs/events.c
new file mode 100644
index 000000000000..efce062f5c48
--- /dev/null
+++ b/fs/ecryptfs/events.c
@@ -0,0 +1,212 @@
+/**
+ * eCryptfs: Linux filesystem encryption layer
+ * Copyright (c) 2015, The Linux Foundation. All rights reserved.
+ *
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License version 2 and
+ * only version 2 as published by the Free Software Foundation.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU General Public License for more details.
+ */
+
+#include <linux/string.h>
+#include <linux/ecryptfs.h>
+#include <linux/mutex.h>
+#include <linux/types.h>
+#include <linux/slab.h>
+#include <linux/pagemap.h>
+#include <linux/random.h>
+#include "ecryptfs_kernel.h"
+
+static DEFINE_MUTEX(events_mutex);
+struct ecryptfs_events *events_ptr = NULL;
+static int handle;
+
+void ecryptfs_free_events(void)
+{
+	mutex_lock(&events_mutex);
+	if (events_ptr != NULL) {
+		kfree(events_ptr);
+		events_ptr = NULL;
+	}
+
+	mutex_unlock(&events_mutex);
+}
+
+/**
+ * Register to ecryptfs events, by passing callback
+ * functions to be called upon events occurence.
+ * The function returns a handle to be passed
+ * to unregister function.
+ */
+int ecryptfs_register_to_events(struct ecryptfs_events *ops)
+{
+	int ret_value = 0;
+
+	if (!ops)
+		return -EINVAL;
+
+	mutex_lock(&events_mutex);
+
+	if (events_ptr != NULL) {
+		ecryptfs_printk(KERN_ERR,
+			"already registered!\n");
+		ret_value = -EPERM;
+		goto out;
+	}
+	events_ptr =
+		kzalloc(sizeof(struct ecryptfs_events), GFP_KERNEL);
+
+	if (!events_ptr) {
+		ecryptfs_printk(KERN_ERR, "malloc failure\n");
+		ret_value = -ENOMEM;
+		goto out;
+	}
+	/* copy the callbacks */
+	events_ptr->open_cb = ops->open_cb;
+	events_ptr->release_cb = ops->release_cb;
+	events_ptr->encrypt_cb = ops->encrypt_cb;
+	events_ptr->decrypt_cb = ops->decrypt_cb;
+	events_ptr->is_cipher_supported_cb =
+		ops->is_cipher_supported_cb;
+	events_ptr->is_hw_crypt_cb = ops->is_hw_crypt_cb;
+
+	get_random_bytes(&handle, sizeof(handle));
+	ret_value = handle;
+
+out:
+	mutex_unlock(&events_mutex);
+	return ret_value;
+}
+
+/**
+ * Unregister from ecryptfs events.
+ */
+int ecryptfs_unregister_from_events(int user_handle)
+{
+	int ret_value = 0;
+
+	mutex_lock(&events_mutex);
+
+	if (!events_ptr) {
+		ret_value = -EINVAL;
+		goto out;
+	}
+	if (user_handle != handle) {
+		ret_value = ECRYPTFS_INVALID_EVENTS_HANDLE;
+		goto out;
+	}
+
+	kfree(events_ptr);
+	events_ptr = NULL;
+
+out:
+	mutex_unlock(&events_mutex);
+	return ret_value;
+}
+
+/**
+ * This function decides whether the passed file offset
+ * belongs to ecryptfs metadata or not.
+ * The caller must pass ecryptfs data, which was received in one
+ * of the callback invocations.
+ */
+bool ecryptfs_is_page_in_metadata(void *data, pgoff_t offset)
+{
+
+	struct ecryptfs_crypt_stat *stat = NULL;
+	bool ret = true;
+
+	if (!data) {
+		ecryptfs_printk(KERN_ERR, "ecryptfs_is_page_in_metadata: invalid data parameter\n");
+		ret = false;
+		goto end;
+	}
+	stat = (struct ecryptfs_crypt_stat *)data;
+
+	if (stat->flags & ECRYPTFS_METADATA_IN_XATTR) {
+		ret = false;
+		goto end;
+	}
+
+	if (offset >= (stat->metadata_size/PAGE_CACHE_SIZE)) {
+		ret = false;
+		goto end;
+	}
+end:
+	return ret;
+}
+
+/**
+ * Given two ecryptfs data, the function
+ * decides whether they are equal.
+ */
+inline bool ecryptfs_is_data_equal(void *data1, void *data2)
+{
+	/* pointer comparison*/
+	return data1 == data2;
+}
+
+/**
+ * Given ecryptfs data, the function
+ * returns appropriate key size.
+ */
+size_t ecryptfs_get_key_size(void *data)
+{
+
+	struct ecryptfs_crypt_stat *stat = NULL;
+
+	if (!data)
+		return 0;
+
+	stat = (struct ecryptfs_crypt_stat *)data;
+	return stat->key_size;
+}
+
+/**
+ * Given ecryptfs data, the function
+ * returns appropriate cipher.
+ */
+const unsigned char *ecryptfs_get_cipher(void *data)
+{
+
+	struct ecryptfs_crypt_stat *stat = NULL;
+
+	if (!data) {
+		ecryptfs_printk(KERN_ERR,
+			"ecryptfs_get_cipher: invalid data parameter\n");
+		return NULL;
+	}
+	stat = (struct ecryptfs_crypt_stat *)data;
+	return ecryptfs_get_full_cipher(stat->cipher, stat->cipher_mode);
+}
+
+/**
+ * Given ecryptfs data, the function
+ * returns file encryption key.
+ */
+const unsigned char *ecryptfs_get_key(void *data)
+{
+
+	struct ecryptfs_crypt_stat *stat = NULL;
+
+	if (!data) {
+		ecryptfs_printk(KERN_ERR,
+			"ecryptfs_get_key: invalid data parameter\n");
+		return NULL;
+	}
+	stat = (struct ecryptfs_crypt_stat *)data;
+	return stat->key;
+}
+
+/**
+ * Returns ecryptfs events pointer
+ */
+inline struct ecryptfs_events *get_events(void)
+{
+	return events_ptr;
+}
+