Add call-gates to px4_crypto for protected build

This adds kernel-userspace interfaces to crypto layer

Signed-off-by: Jukka Laitinen <jukkax@ssrc.tii.ae>

platforms/common/include/px4_platform_common/crypto.h

@@ -208,6 +208,8 @@ public:
 
 	size_t get_min_blocksize(uint8_t key_idx);
 
+	static int crypto_ioctl(unsigned int cmd, unsigned long arg);
+
 private:
 	crypto_session_handle_t _crypto_handle;
 	static px4_sem_t _lock;

platforms/common/include/px4_platform_common/crypto_backend.h

@@ -39,6 +39,7 @@ extern "C" {
 
 #include <stdbool.h>
 #include <stdint.h>
+#include <sys/ioctl.h>
 #include <px4_platform_common/crypto_algorithms.h>
 #include "crypto_backend_definitions.h"
 
@@ -181,6 +182,63 @@ bool crypto_encrypt_data(crypto_session_handle_t handle,
 
 size_t crypto_get_min_blocksize(crypto_session_handle_t handle, uint8_t key_idx);
 
+
+/* Crypto IOCTLs, to access backend from user space */
+
+#define _CRYPTOIOC(_n)		(_IOC(_CRYPTOIOCBASE, _n))
+
+#define CRYPTOIOCOPEN _CRYPTOIOC(1)
+typedef struct cryptoiocopen {
+	px4_crypto_algorithm_t algorithm;
+	crypto_session_handle_t *handle;
+} cryptoiocopen_t;
+
+#define CRYPTOIOCCLOSE _CRYPTOIOC(2)
+
+#define CRYPTOIOCENCRYPT _CRYPTOIOC(3)
+typedef struct cryptoiocencrypt {
+	crypto_session_handle_t *handle;
+	uint8_t  key_index;
+	const uint8_t *message;
+	size_t message_size;
+	uint8_t *cipher;
+	size_t *cipher_size;
+	bool ret;
+} cryptoiocencrypt_t;
+
+#define CRYPTOIOCGENKEY _CRYPTOIOC(4)
+typedef struct cryptoiocgenkey {
+	crypto_session_handle_t *handle;
+	uint8_t idx;
+	bool persistent;
+	bool ret;
+} cryptoiocgenkey_t;
+
+#define CRYPTOIOCGETNONCE _CRYPTOIOC(5)
+typedef struct cryptoiocgetnonce {
+	crypto_session_handle_t *handle;
+	uint8_t *nonce;
+	size_t *nonce_len;
+	bool ret;
+} cryptoiocgetnonce_t;
+
+#define CRYPTOIOCGETKEY _CRYPTOIOC(6)
+typedef struct cryptoiocgetkey {
+	crypto_session_handle_t *handle;
+	uint8_t key_idx;
+	uint8_t *key;
+	size_t *max_len;
+	uint8_t encryption_key_idx;
+	bool ret;
+} cryptoiocgetkey_t;
+
+#define CRYPTOIOCGETBLOCKSZ _CRYPTOIOC(7)
+typedef struct cryptoiocgetblocksz {
+	crypto_session_handle_t *handle;
+	uint8_t key_idx;
+	size_t ret;
+} cryptoiocgetblocksz_t;
+
 #if defined(__cplusplus)
 } // extern "C"
 #endif

platforms/nuttx/src/px4/common/px4_crypto.cpp

@@ -35,6 +35,8 @@
 
 #include <px4_platform_common/crypto.h>
 #include <px4_platform_common/crypto_backend.h>
+#include <px4_platform_common/defines.h>
+#include <px4_platform/board_ctrl.h>
 
 extern "C" {
 #include <nuttx/random.h>
@@ -63,6 +65,11 @@ void PX4Crypto::px4_crypto_init()
 	// initialize actual crypto algoritms
 	crypto_init();
 
+	// initialize user ioctl interface for crypto
+#if !defined(CONFIG_BUILD_FLAT)
+	px4_register_boardct_ioctl(_CRYPTOIOCBASE, crypto_ioctl);
+#endif
+
 	PX4Crypto::_initialized = true;
 }
 
@@ -146,4 +153,63 @@ size_t PX4Crypto::get_min_blocksize(uint8_t key_idx)
 	return crypto_get_min_blocksize(_crypto_handle, key_idx);
 }
 
+#if !defined(CONFIG_BUILD_FLAT)
+int PX4Crypto::crypto_ioctl(unsigned int cmd, unsigned long arg)
+{
+	int ret = PX4_OK;
+
+	switch (cmd) {
+	case CRYPTOIOCOPEN: {
+			cryptoiocopen_t *data = (cryptoiocopen_t *)arg;
+			*(data->handle) = crypto_open(data->algorithm);
+		}
+		break;
+
+	case CRYPTOIOCCLOSE: {
+			crypto_close((crypto_session_handle_t *)arg);
+		}
+		break;
+
+	case CRYPTOIOCENCRYPT: {
+			cryptoiocencrypt_t *data = (cryptoiocencrypt_t *)arg;
+			data->ret = crypto_encrypt_data(*(data->handle), data->key_index, data->message, data->message_size, data->cipher,
+							data->cipher_size);
+		}
+		break;
+
+	case CRYPTOIOCGENKEY: {
+			cryptoiocgenkey_t *data = (cryptoiocgenkey_t *)arg;
+			data->ret = crypto_generate_key(*(data->handle), data->idx, data->persistent);
+		}
+		break;
+
+	case CRYPTOIOCGETNONCE: {
+			cryptoiocgetnonce_t *data = (cryptoiocgetnonce_t *)arg;
+			data->ret = crypto_get_nonce(*(data->handle), data->nonce, data->nonce_len);
+
+		}
+		break;
+
+	case CRYPTOIOCGETKEY: {
+			cryptoiocgetkey_t *data = (cryptoiocgetkey_t *)arg;
+			data->ret = crypto_get_encrypted_key(*(data->handle), data->key_idx, data->key, data->max_len,
+							     data->encryption_key_idx);
+		}
+		break;
+
+	case CRYPTOIOCGETBLOCKSZ: {
+			cryptoiocgetblocksz_t *data = (cryptoiocgetblocksz_t *)arg;
+			data->ret = crypto_get_min_blocksize(*(data->handle), data->key_idx);
+		}
+		break;
+
+	default:
+		ret = PX4_ERROR;
+		break;
+	}
+
+	return ret;
+}
+#endif // !defined(CONFIG_BUILD_FLAT)
+
 #endif

platforms/nuttx/src/px4/common/px4_protected_layers.cmake

@@ -12,6 +12,7 @@ add_library(px4_layer
 	${PX4_SOURCE_DIR}/platforms/posix/src/px4/common/cpuload.cpp
 	usr_hrt.cpp
 	px4_userspace_init.cpp
+	px4_usr_crypto.cpp
 )
 
 target_link_libraries(px4_layer
@@ -55,6 +56,7 @@ target_link_libraries(px4_kernel_layer
 
 if (DEFINED PX4_CRYPTO)
 	target_link_libraries(px4_kernel_layer PUBLIC crypto_backend)
+	target_link_libraries(px4_layer PUBLIC crypto_backend_interface)
 endif()
 
 target_compile_options(px4_kernel_layer PRIVATE -D__KERNEL__)

platforms/nuttx/src/px4/common/px4_usr_crypto.cpp

@@ -0,0 +1,123 @@
+/****************************************************************************
+ *
+ *   Copyright (c) 2021 Technology Innovation Institute. All rights reserved.
+ *
+ * Redistribution and use in source and binary forms, with or without
+ * modification, are permitted provided that the following conditions
+ * are met:
+ *
+ * 1. Redistributions of source code must retain the above copyright
+ *    notice, this list of conditions and the following disclaimer.
+ * 2. Redistributions in binary form must reproduce the above copyright
+ *    notice, this list of conditions and the following disclaimer in
+ *    the documentation and/or other materials provided with the
+ *    distribution.
+ * 3. Neither the name PX4 nor the names of its contributors may be
+ *    used to endorse or promote products derived from this software
+ *    without specific prior written permission.
+ *
+ * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
+ * "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
+ * LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS
+ * FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE
+ * COPYRIGHT OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT,
+ * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING,
+ * BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS
+ * OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED
+ * AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
+ * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN
+ * ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
+ * POSSIBILITY OF SUCH DAMAGE.
+ *
+ ****************************************************************************/
+
+#if defined(PX4_CRYPTO)
+
+#include <px4_platform_common/crypto.h>
+#include <px4_platform_common/crypto_backend.h>
+#include <sys/boardctl.h>
+
+bool PX4Crypto::_initialized = false;
+
+void PX4Crypto::px4_crypto_init()
+{
+	PX4Crypto::_initialized = true;
+}
+
+PX4Crypto::PX4Crypto()
+{
+	// Initialize an empty handle
+	crypto_session_handle_init(&_crypto_handle);
+}
+
+PX4Crypto::~PX4Crypto()
+{
+	close();
+}
+
+bool PX4Crypto::open(px4_crypto_algorithm_t algorithm)
+{
+	// HW specific crypto already open? Just close before proceeding
+	close();
+
+	// Open the HW specific crypto handle
+	cryptoiocopen_t data = {algorithm, &_crypto_handle};
+	boardctl(CRYPTOIOCOPEN, reinterpret_cast<unsigned long>(&data));
+
+	return crypto_session_handle_valid(_crypto_handle);
+}
+
+void PX4Crypto::close()
+{
+	if (!crypto_session_handle_valid(_crypto_handle)) {
+		return;
+	}
+
+	boardctl(CRYPTOIOCCLOSE, reinterpret_cast<unsigned long>(&_crypto_handle));
+}
+
+bool PX4Crypto::encrypt_data(uint8_t  key_index,
+			     const uint8_t *message,
+			     size_t message_size,
+			     uint8_t *cipher,
+			     size_t *cipher_size)
+{
+	cryptoiocencrypt_t data = {&_crypto_handle, key_index, message, message_size, cipher, cipher_size, false};
+	boardctl(CRYPTOIOCENCRYPT, reinterpret_cast<unsigned long>(&data));
+	return data.ret;
+}
+
+bool  PX4Crypto::generate_key(uint8_t idx,
+			      bool persistent)
+{
+	cryptoiocgenkey_t data = {&_crypto_handle, idx, persistent, false};
+	boardctl(CRYPTOIOCGENKEY, reinterpret_cast<unsigned long>(&data));
+	return data.ret;
+}
+
+bool  PX4Crypto::get_nonce(uint8_t *nonce,
+			   size_t *nonce_len)
+{
+	cryptoiocgetnonce_t data = {&_crypto_handle, nonce, nonce_len, false};
+	boardctl(CRYPTOIOCGETNONCE, reinterpret_cast<unsigned long>(&data));
+	return data.ret;
+}
+
+bool  PX4Crypto::get_encrypted_key(uint8_t key_idx,
+				   uint8_t *key,
+				   size_t *key_len,
+				   uint8_t encryption_key_idx)
+{
+	cryptoiocgetkey_t data = {&_crypto_handle, key_idx, key, key_len, encryption_key_idx, false};
+	boardctl(CRYPTOIOCGETKEY, reinterpret_cast<unsigned long>(&data));
+	return data.ret;
+}
+
+size_t PX4Crypto::get_min_blocksize(uint8_t key_idx)
+{
+	cryptoiocgetblocksz_t data = {&_crypto_handle, key_idx, 0};
+	boardctl(CRYPTOIOCGETBLOCKSZ, reinterpret_cast<unsigned long>(&data));
+	return data.ret;
+}
+
+#endif