feat(dice): add typedefs from the Open DICE repo

The DPE implementation in RSS is aligned with the
Open Profile for DICE specification:
https://pigweed.googlesource.com/open-dice/

Type definitions are needed to specify the input
values for the DPE service. Instead of mandating to
clone the entire open-dice repo, the following file
is copied from the repository:
https://pigweed.googlesource.com/open-dice/+/refs/heads/main/include/dice/dice.h
Git SHA of the source version: cf549422e39da872d64993be944099ac62ba22a9

This is external code, with Apache 2.0 license, therefore
the license.rst is updated accordingly and a copy of this
license is also added.

Signed-off-by: Tamas Ban <tamas.ban@arm.com>
Signed-off-by: David Vincze <david.vincze@arm.com>
Change-Id: Ie84b8483034819d1143fe0ec812e66514ac7d4cb
diff --git a/include/lib/dice/dice.h b/include/lib/dice/dice.h
new file mode 100644
index 0000000..cf54942
--- /dev/null
+++ b/include/lib/dice/dice.h
@@ -0,0 +1,166 @@
+// Copyright 2020 Google LLC
+//
+// Licensed under the Apache License, Version 2.0 (the "License"); you may not
+// use this file except in compliance with the License. You may obtain a copy of
+// the License at
+//
+//     https://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS, WITHOUT
+// WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. See the
+// License for the specific language governing permissions and limitations under
+// the License.
+
+#ifndef DICE_DICE_H_
+#define DICE_DICE_H_
+
+#include <stddef.h>
+#include <stdint.h>
+
+#ifdef __cplusplus
+extern "C" {
+#endif
+
+#define DICE_CDI_SIZE 32
+#define DICE_HASH_SIZE 64
+#define DICE_HIDDEN_SIZE 64
+#define DICE_INLINE_CONFIG_SIZE 64
+#define DICE_PRIVATE_KEY_SEED_SIZE 32
+#define DICE_ID_SIZE 20
+
+typedef enum {
+  kDiceResultOk,
+  kDiceResultInvalidInput,
+  kDiceResultBufferTooSmall,
+  kDiceResultPlatformError,
+} DiceResult;
+
+typedef enum {
+  kDiceModeNotInitialized,
+  kDiceModeNormal,
+  kDiceModeDebug,
+  kDiceModeMaintenance,
+} DiceMode;
+
+typedef enum {
+  kDiceConfigTypeInline,
+  kDiceConfigTypeDescriptor,
+} DiceConfigType;
+
+// Contains a full set of input values describing the target program or system.
+// See the Open Profile for DICE specification for a detailed explanation of
+// these inputs.
+//
+// Fields:
+//    code_hash: A hash or similar representation of the target code.
+//    code_descriptor: An optional descriptor to be included in the certificate.
+//        This descriptor is opaque to the DICE flow and is included verbatim
+//        in the certificate with no validation. May be null.
+//    code_descriptor_size: The size in bytes of |code_descriptor|.
+//    config_type: Indicates how to interpret the remaining config-related
+//        fields. If the type is 'inline', then the 64 byte configuration input
+//        value must be provided in |config_value| and |config_descriptor| is
+//        ignored. If the type is 'descriptor', then |config_descriptor| is
+//        hashed to get the configuration input value and |config_value| is
+//        ignored.
+//    config_value: A 64-byte configuration input value when |config_type| is
+//        kDiceConfigTypeInline. Otherwise, this field is ignored.
+//    config_descriptor: A descriptor to be hashed for the configuration input
+//        value when |config_type| is kDiceConfigTypeDescriptor. Otherwise,
+//        this field is ignored and may be null.
+//    config_descriptor_size: The size in bytes of |config_descriptor|.
+//    authority_hash: A hash or similar representation of the authority used to
+//        verify the target code. If the code is not verified or the authority
+//        is implicit, for example hard coded as part of the code currently
+//        executing, then this value should be set to all zero bytes.
+//    authority_descriptor: An optional descriptor to be included in the
+//        certificate. This descriptor is opaque to the DICE flow and is
+//        included verbatim in the certificate with no validation. May be null.
+//    authority_descriptor_size: The size in bytes of |authority_descriptor|.
+//    mode: The current operating mode.
+//    hidden: Additional input which will not appear in certificates. If this is
+//        not used it should be set to all zero bytes.
+typedef struct DiceInputValues_ {
+  uint8_t code_hash[DICE_HASH_SIZE];
+  const uint8_t* code_descriptor;
+  size_t code_descriptor_size;
+  DiceConfigType config_type;
+  uint8_t config_value[DICE_INLINE_CONFIG_SIZE];
+  const uint8_t* config_descriptor;
+  size_t config_descriptor_size;
+  uint8_t authority_hash[DICE_HASH_SIZE];
+  const uint8_t* authority_descriptor;
+  size_t authority_descriptor_size;
+  DiceMode mode;
+  uint8_t hidden[DICE_HIDDEN_SIZE];
+} DiceInputValues;
+
+// Derives a |cdi_private_key_seed| from a |cdi_attest| value. On success
+// populates |cdi_private_key_seed| and returns kDiceResultOk.
+DiceResult DiceDeriveCdiPrivateKeySeed(
+    void* context, const uint8_t cdi_attest[DICE_CDI_SIZE],
+    uint8_t cdi_private_key_seed[DICE_PRIVATE_KEY_SEED_SIZE]);
+
+// Derives an |id| from a |cdi_public_key| value. Because public keys can vary
+// in length depending on the algorithm, the |cdi_public_key_size| in bytes must
+// be provided. When interpreted as an integer, |id| is big-endian. On success
+// populates |id| and returns kDiceResultOk.
+DiceResult DiceDeriveCdiCertificateId(void* context,
+                                      const uint8_t* cdi_public_key,
+                                      size_t cdi_public_key_size,
+                                      uint8_t id[DICE_ID_SIZE]);
+
+// Executes the main DICE flow.
+//
+// Given a full set of input values and the current CDI values, computes the
+// next CDI values and a matching certificate. See the Open Profile for DICE
+// specification for a detailed explanation of this flow.
+// In certain cases, the caller may not need to generate the CDI certificate.
+// The caller should signal this by setting the certificate parameters to
+// null/zero values appropriately.
+//
+// Parameters:
+//    context: Context provided by the caller that is opaque to this library
+//        but is passed through to the integration-provided operations in
+//        dice/ops.h. The value is, therefore, integration-specific and may be
+//        null.
+//    current_cdi_attest, current_cdi_seal: The current CDI values as produced
+//        by a previous DICE flow. If this is the first DICE flow in a system,
+//        the Unique Device Secret (UDS) should be used for both of these
+//        arguments.
+//    input_values: A set of input values describing the target program or
+//        system.
+//    next_cdi_certificate_buffer_size: The size in bytes of the buffer pointed
+//        to by the |next_cdi_certificate| argument. This should be set to zero
+//        if next CDI certificate should not be computed.
+//    next_cdi_certificate: On success, will be populated with the generated
+//        certificate, up to |next_cdi_certificate_buffer_size| in size. If the
+//        certificate cannot fit in the buffer, |next_cdi_certificate_size| is
+//        populated with the required size and kDiceResultBufferTooSmall is
+//        returned. This should be set to NULL if next CDI certificate should
+//        not be computed.
+//    next_cdi_certificate_actual_size: On success, will be populated with the
+//        size, in bytes, of the certificate data written to
+//        |next_cdi_certificate|. If kDiceResultBufferTooSmall is returned, will
+//        be populated with the required buffer size. This should be set to NULL
+//        if next CDI certificate should not be computed.
+//    next_cdi_attest: On success, will be populated with the next CDI value for
+//        attestation.
+//    next_cdi_seal: On success, will be populated with the next CDI value for
+//        sealing.
+DiceResult DiceMainFlow(void* context,
+                        const uint8_t current_cdi_attest[DICE_CDI_SIZE],
+                        const uint8_t current_cdi_seal[DICE_CDI_SIZE],
+                        const DiceInputValues* input_values,
+                        size_t next_cdi_certificate_buffer_size,
+                        uint8_t* next_cdi_certificate,
+                        size_t* next_cdi_certificate_actual_size,
+                        uint8_t next_cdi_attest[DICE_CDI_SIZE],
+                        uint8_t next_cdi_seal[DICE_CDI_SIZE]);
+
+#ifdef __cplusplus
+}  // extern "C"
+#endif
+
+#endif  // DICE_DICE_H_