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/*
* Copyright (c) 2016 Intel Corporation.
*
* SPDX-License-Identifier: Apache-2.0
*/
/**
* @file
* @brief Crypto Cipher APIs
*
* This file contains the Crypto Abstraction layer APIs.
*
* [Experimental] Users should note that the APIs can change
* as a part of ongoing development.
*/
#ifndef ZEPHYR_INCLUDE_CRYPTO_CIPHER_H_
#define ZEPHYR_INCLUDE_CRYPTO_CIPHER_H_
#include <device.h>
#include <errno.h>
#include <sys/util.h>
#include <sys/__assert.h>
#include "cipher_structs.h"
/* The API a crypto driver should implement */
struct crypto_driver_api {
int (*query_hw_caps)(struct device *dev);
/* Setup a crypto session */
int (*begin_session)(struct device *dev, struct cipher_ctx *ctx,
enum cipher_algo algo, enum cipher_mode mode,
enum cipher_op op_type);
/* Tear down an established session */
int (*free_session)(struct device *dev, struct cipher_ctx *ctx);
/* Register async crypto op completion callback with the driver*/
int (*crypto_async_callback_set)(struct device *dev,
crypto_completion_cb cb);
};
/* Following are the calls an app could make to get cipher stuff done.
* The first two relates to crypto "session" setup / tear down.
* Further we have four mode specific (CTR, CCM, CBC ...) calls to perform the
* actual crypto operation in the context of a session. Also we have an
* API to provide the callback for async operations.
*/
/*
* @brief Query the crypto hardware capabilities
*
* This API is used by the app to query the capabilities supported by the
* crypto device. Based on this the app can specify a subset of the supported
* options to be honored for a session during cipher_begin_session()
*
* @param[in] dev Pointer to the device structure for the driver instance.
*
* @return bitmask of supported options.
*/
static inline int cipher_query_hwcaps(struct device *dev)
{
struct crypto_driver_api *api;
int tmp;
api = (struct crypto_driver_api *) dev->driver_api;
tmp = api->query_hw_caps(dev);
__ASSERT((tmp & (CAP_OPAQUE_KEY_HNDL | CAP_RAW_KEY)) != 0,
"Driver should support atleast one key type: RAW/Opaque");
__ASSERT((tmp & (CAP_INPLACE_OPS | CAP_SEPARATE_IO_BUFS)) != 0,
"Driver should support atleast one IO buf type: Inplace/separate");
__ASSERT((tmp & (CAP_SYNC_OPS | CAP_ASYNC_OPS)) != 0,
"Driver should support atleast one op-type: sync/async");
return tmp;
}
/*
* @brief Setup a crypto session
*
* Initializes one time parameters, like the session key, algorithm and cipher
* mode which may remain constant for all operations in the session. The state
* may be cached in hardware and/or driver data state variables.
*
* @param[in] dev Pointer to the device structure for the driver instance.
* @param[in] ctx Pointer to the context structure. Various one time
* parameters like key, keylength etc are supplied via
* this field. Take a look at the ctx structure definition
* to know which fields are to be populated by the app
* before making this call.
* @param[in] algo The crypto algorithm to be used in this session. e.g AES
* @param[in] mode The cipher mode to be used in this session. e.g CBC, CTR
* @param[in] optype Whether we should encrypt or decrypt in this session
* @return 0 on success, negative errno code on fail.
*/
static inline int cipher_begin_session(struct device *dev,
struct cipher_ctx *ctx,
enum cipher_algo algo,
enum cipher_mode mode,
enum cipher_op optype)
{
struct crypto_driver_api *api;
u32_t flags;
api = (struct crypto_driver_api *) dev->driver_api;
ctx->device = dev;
ctx->ops.cipher_mode = mode;
flags = (ctx->flags & (CAP_OPAQUE_KEY_HNDL | CAP_RAW_KEY));
__ASSERT(flags != 0U, "Keytype missing: RAW Key or OPAQUE handle");
__ASSERT(flags != (CAP_OPAQUE_KEY_HNDL | CAP_RAW_KEY),
"conflicting options for keytype");
flags = (ctx->flags & (CAP_INPLACE_OPS | CAP_SEPARATE_IO_BUFS));
__ASSERT(flags != 0U, "IO buffer type missing");
__ASSERT(flags != (CAP_INPLACE_OPS | CAP_SEPARATE_IO_BUFS),
"conflicting options for IO buffer type");
flags = (ctx->flags & (CAP_SYNC_OPS | CAP_ASYNC_OPS));
__ASSERT(flags != 0U, "sync/async type missing");
__ASSERT(flags != (CAP_SYNC_OPS | CAP_ASYNC_OPS),
"conflicting options for sync/async");
return api->begin_session(dev, ctx, algo, mode, optype);
}
/*
* @brief Cleanup a crypto session
*
* Clears the hardware and/or driver state of a previous session.
*
* @param[in] dev Pointer to the device structure for the driver instance.
* @param[in] ctx Pointer to the crypto context structure, of the session
* to be freed.
*
* @return 0 on success, negative errno code on fail.
*/
static inline int cipher_free_session(struct device *dev,
struct cipher_ctx *ctx)
{
struct crypto_driver_api *api;
api = (struct crypto_driver_api *) dev->driver_api;
return api->free_session(dev, ctx);
}
/*
* @brief Registers an async crypto op completion callback with the driver
*
* The application can register an async crypto op completion callback handler
* to be invoked by the driver, on completion of a prior request submitted via
* crypto_do_op(). Based on crypto device hardware semantics, this is likely to
* be invoked from an ISR context.
*
* @param[in] dev Pointer to the device structure for the driver instance.
* @param[in] cb Pointer to application callback to be called by the driver.
*
* @return 0 on success, -ENOTSUP if the driver does not support async op,
* negative errno code on fail.
*/
static inline int cipher_callback_set(struct device *dev,
crypto_completion_cb cb)
{
struct crypto_driver_api *api;
api = (struct crypto_driver_api *) dev->driver_api;
if (api->crypto_async_callback_set) {
return api->crypto_async_callback_set(dev, cb);
}
return -ENOTSUP;
}
/*
* @brief Perform Single block crypto op. This should not be overloaded to
* operate on multiple blocks for security reasons.
*
* @param[in] ctx Pointer to the crypto context of this op.
* @param[in/out] pkt Structure holding the Input/Output buffer pointers.
*
* @return 0 on success, negative errno code on fail.
*/
static inline int cipher_block_op(struct cipher_ctx *ctx,
struct cipher_pkt *pkt)
{
__ASSERT(ctx->ops.cipher_mode == CRYPTO_CIPHER_MODE_ECB, "ECB mode "
"session invoking a different mode handler");
pkt->ctx = ctx;
return ctx->ops.block_crypt_hndlr(ctx, pkt);
}
/*
* @brief Perform Cipher Block Chaining (CBC) crypto operation.
*
* @param[in] ctx Pointer to the crypto context of this op.
* @param[in/out] pkt Structure holding the Input/Output buffer pointers.
* @param[in] iv Initialization Vector for the operation. Same
* iv value should not be reused across multiple
* operations (within a session context) for security.
*
* @return 0 on success, negative errno code on fail.
*/
static inline int cipher_cbc_op(struct cipher_ctx *ctx,
struct cipher_pkt *pkt, u8_t *iv)
{
__ASSERT(ctx->ops.cipher_mode == CRYPTO_CIPHER_MODE_CBC, "CBC mode "
"session invoking a different mode handler");
pkt->ctx = ctx;
return ctx->ops.cbc_crypt_hndlr(ctx, pkt, iv);
}
/*
* @brief Perform Counter (CTR) mode crypto operation.
*
* @param[in] ctx Pointer to the crypto context of this op.
* @param[in/out] pkt Structure holding the Input/Output buffer pointers.
* @param[in] iv Initialization Vector for the operation. We use a
* split counter formed by appending iv and ctr.
* Consequently ivlen = keylen - ctrlen. 'ctrlen' is
* specified during session setup through the
* 'ctx.mode_params.ctr_params.ctr_len' parameter. IV
* should not be reused across multiple operations
* (within a session context) for security. The non-iv
* part of the split counter is transparent to the caller
* and is fully managed by the crypto provider.
*
* @return 0 on success, negative errno code on fail.
*/
static inline int cipher_ctr_op(struct cipher_ctx *ctx,
struct cipher_pkt *pkt, u8_t *iv)
{
__ASSERT(ctx->ops.cipher_mode == CRYPTO_CIPHER_MODE_CTR, "CTR mode "
"session invoking a different mode handler");
pkt->ctx = ctx;
return ctx->ops.ctr_crypt_hndlr(ctx, pkt, iv);
}
/*
* @brief Perform Counter with CBC-MAC (CCM) mode crypto operation
*
* @param[in] ctx Pointer to the crypto context of this op.
* @param[in/out] pkt Structure holding the Input/Output, Assosciated Data
* and tag buffer pointers.
* @param[in] nonce Nonce for the operation. Same Nonce value should not
* be reused across multiple operations (within a
* session context) for security.
*
* @return 0 on success, negative errno code on fail.
*/
static inline int cipher_ccm_op(struct cipher_ctx *ctx,
struct cipher_aead_pkt *pkt, u8_t *nonce)
{
__ASSERT(ctx->ops.cipher_mode == CRYPTO_CIPHER_MODE_CCM, "CCM mode "
"session invoking a different mode handler");
pkt->pkt->ctx = ctx;
return ctx->ops.ccm_crypt_hndlr(ctx, pkt, nonce);
}
#endif /* ZEPHYR_INCLUDE_CRYPTO_CIPHER_H_ */