From 4b09ffef49663ebc8c8f5c3da19636208fe2fa06 Mon Sep 17 00:00:00 2001 From: Tamas Ban Date: Wed, 31 Aug 2022 14:50:27 +0200 Subject: [PATCH] feat(psa): add delegated attestation partition API Delegated attestation is a service provided by RSS to: - Derive a delegated attestation key: Realm Attestation Key - Query the platform attestation token Signed-off-by: Tamas Ban Change-Id: I3edf09fcbef24bca7c8a000ffac8c1ab64dfb812 --- include/lib/psa/delegated_attestation.h | 109 +++++++++++ include/lib/psa/psa_manifest/sid.h | 3 + lib/psa/delegated_attestation.c | 230 ++++++++++++++++++++++++ 3 files changed, 342 insertions(+) create mode 100644 include/lib/psa/delegated_attestation.h create mode 100644 lib/psa/delegated_attestation.c diff --git a/include/lib/psa/delegated_attestation.h b/include/lib/psa/delegated_attestation.h new file mode 100644 index 000000000..7aaceb3e3 --- /dev/null +++ b/include/lib/psa/delegated_attestation.h @@ -0,0 +1,109 @@ +/* + * Copyright (c) 2022, Arm Limited. All rights reserved. + * + * SPDX-License-Identifier: BSD-3-Clause + * + */ + +/* This file describes the Delegated Attestation API */ + +#ifndef DELEGATED_ATTESTATION_H +#define DELEGATED_ATTESTATION_H + +#include +#include + +#include "psa/error.h" + +/* RSS Delegated Attestation message types that distinguish its services. */ +#define RSS_DELEGATED_ATTEST_GET_DELEGATED_KEY 1001U +#define RSS_DELEGATED_ATTEST_GET_PLATFORM_TOKEN 1002U + +/** + * The aim of these APIs to get a derived signing key (private only) for the + * delegated attestation model and obtain the corresponding platform attestation + * token. In the delegated attestation model the final token consist of more + * than one subtokens which are signed by different entities. There is a + * cryptographical binding between the tokens. The derived delegated attestation + * key is bind to the platform token (details below). + * + * Expected usage model: + * - First rss_delegated_attest_get_delegated_key() API need to be called to + * obtain the private part of the delegated attestation key. The public part + * of key is computed by the cryptographic library when the key is + * registered. + * - Secondly the rss_delegated_attest_get_token() must be called to obtain + * platform attestation token. The hash of the public key (computed by + * the hash_algo indicated in the rss_delegated_attest_get_delegated_key() + * call) must be the input of this call. This ensures that nothing but the + * previously derived delegated key is bindable to the platform token. + */ + +/** + * Get a delegated attestation key (DAK). + * + * The aim of the delegated attestation key is to enable other SW components + * within the system to sign an attestation token which is different than the + * initial/platform token. The initial attestation token MUST contain the hash + * of the public delegated key to make a cryptographical binding (hash lock) + * between the key and the token. + * The initial attestation token has two roles in this scenario: + * - Attest the device boot status and security lifecycle. + * - Attest the delegated attestation key. + * The delegated attestation key is derived from a preprovisioned seed. The + * input for the key derivation is the platform boot status. The system can be + * attestated with the two tokens together. + * + * ecc_curve The type of the elliptic curve to which the requested + * attestation key belongs. Please check the note section for + * limitations. + * key_bits The size of the requested attestation key, in bits. + * key_buf Pointer to the buffer where the delegated attestation key will + * be stored. + * key_buf_size Size of allocated buffer for the key, in bytes. + * key_size Size of the key that has been returned, in bytes. + * hash_algo The hash algorithm that will be used later by the owner of the + * requested delegated key for binding it to the platform + * attestation token. + * + * Returns error code as specified in psa_status_t. + * + * Notes: + * - Currently, only the PSA_ECC_FAMILY_SECP_R1 curve type is supported. + * - The delegated attestation key must be derived before requesting for the + * platform attestation token as they are cryptographically linked together. + */ +psa_status_t +rss_delegated_attest_get_delegated_key(uint8_t ecc_curve, + uint32_t key_bits, + uint8_t *key_buf, + size_t key_buf_size, + size_t *key_size, + uint32_t hash_algo); + +/** + * Get platform attestation token + * + * dak_pub_hash Pointer to buffer where the hash of the public DAK is + * stored. + * dak_pub_hash_size Size of the hash value, in bytes. + * token_buf Pointer to the buffer where the platform attestation token + * will be stored. + * token_buf_size Size of allocated buffer for token, in bytes. + * token_size Size of the token that has been returned, in bytes. + * + * Returns error code as specified in psa_status_t. + * + * A delegated attestation key must be derived before requesting for the + * platform attestation token as they are cryptographically linked together. + * Otherwise, the token request will fail and the PSA_ERROR_INVALID_ARGUMENT + * code will be returned. + */ +psa_status_t +rss_delegated_attest_get_token(const uint8_t *dak_pub_hash, + size_t dak_pub_hash_size, + uint8_t *token_buf, + size_t token_buf_size, + size_t *token_size); + +#endif /* DELEGATED_ATTESTATION_H */ diff --git a/include/lib/psa/psa_manifest/sid.h b/include/lib/psa/psa_manifest/sid.h index 580a4cf70..bbd2e227a 100644 --- a/include/lib/psa/psa_manifest/sid.h +++ b/include/lib/psa/psa_manifest/sid.h @@ -14,4 +14,7 @@ /******** PSA_SP_MEASURED_BOOT ********/ #define RSS_MEASURED_BOOT_HANDLE (0x40000110U) +/******** PSA_SP_DELAGATED_ATTESTATION ********/ +#define RSS_DELEGATED_SERVICE_HANDLE (0x40000111U) + #endif /* PSA_MANIFEST_SID_H */ diff --git a/lib/psa/delegated_attestation.c b/lib/psa/delegated_attestation.c new file mode 100644 index 000000000..5acab8eb5 --- /dev/null +++ b/lib/psa/delegated_attestation.c @@ -0,0 +1,230 @@ +/* + * Copyright (c) 2022, Arm Limited. All rights reserved. + * + * SPDX-License-Identifier: BSD-3-Clause + * + */ + +#include + +#include +#include +#include + +#if !PLAT_RSS_NOT_SUPPORTED +psa_status_t +rss_delegated_attest_get_delegated_key(uint8_t ecc_curve, + uint32_t key_bits, + uint8_t *key_buf, + size_t key_buf_size, + size_t *key_size, + uint32_t hash_algo) +{ + psa_status_t status; + psa_invec in_vec[] = { + {&ecc_curve, sizeof(ecc_curve)}, + {&key_bits, sizeof(key_bits)}, + {&hash_algo, sizeof(hash_algo)} + }; + psa_outvec out_vec[] = { + {key_buf, key_buf_size} + }; + + if (key_size == NULL) { + return PSA_ERROR_INVALID_ARGUMENT; + } + + status = psa_call(RSS_DELEGATED_SERVICE_HANDLE, + RSS_DELEGATED_ATTEST_GET_DELEGATED_KEY, + in_vec, IOVEC_LEN(in_vec), + out_vec, IOVEC_LEN(out_vec)); + if (status == PSA_SUCCESS) { + *key_size = out_vec[0].len; + } + + return status; +} + +psa_status_t +rss_delegated_attest_get_token(const uint8_t *dak_pub_hash, + size_t dak_pub_hash_size, + uint8_t *token_buf, + size_t token_buf_size, + size_t *token_size) +{ + psa_status_t status; + psa_invec in_vec[] = { + {dak_pub_hash, dak_pub_hash_size} + }; + psa_outvec out_vec[] = { + {token_buf, token_buf_size} + }; + + if (token_size == NULL) { + return PSA_ERROR_INVALID_ARGUMENT; + } + + status = psa_call(RSS_DELEGATED_SERVICE_HANDLE, + RSS_DELEGATED_ATTEST_GET_PLATFORM_TOKEN, + in_vec, IOVEC_LEN(in_vec), + out_vec, IOVEC_LEN(out_vec)); + if (status == PSA_SUCCESS) { + *token_size = out_vec[0].len; + } + + return status; +} + + +#else /* !PLAT_RSS_NOT_SUPPORTED */ + +static const uint8_t delegated_key[] = { + 0x20, 0x11, 0xC7, 0xF0, 0x3C, 0xEE, 0x43, 0x25, 0x17, 0x6E, + 0x52, 0x4F, 0x03, 0x3C, 0x0C, 0xE1, 0xE2, 0x1A, 0x76, 0xE6, + 0xC1, 0xA4, 0xF0, 0xB8, 0x39, 0xAA, 0x1D, 0xF6, 0x1E, 0x0E, + 0x8A, 0x5C, 0x8A, 0x05, 0x74, 0x0F, 0x9B, 0x69, 0xEF, 0xA7, + 0xEB, 0x1A, 0x41, 0x85, 0xBD, 0x11, 0x7F, 0x68 +} + +static const uint8_t platform_token[] = { + 0xD2, 0x84, 0x43, 0xA1, 0x01, 0x26, 0xA0, 0x59, + 0x02, 0xBE, 0xAA, 0x3A, 0x00, 0x01, 0x24, 0xFF, + 0x58, 0x20, 0xAB, 0xAB, 0xAB, 0xAB, 0xAB, 0xAB, + 0xAB, 0xAB, 0xAB, 0xAB, 0xAB, 0xAB, 0xAB, 0xAB, + 0xAB, 0xAB, 0xAB, 0xAB, 0xAB, 0xAB, 0xAB, 0xAB, + 0xAB, 0xAB, 0xAB, 0xAB, 0xAB, 0xAB, 0xAB, 0xAB, + 0xAB, 0xAB, 0x3A, 0x00, 0x01, 0x24, 0xFB, 0x58, + 0x20, 0xA0, 0xA1, 0xA2, 0xA3, 0xA4, 0xA5, 0xA6, + 0xA7, 0xA8, 0xA9, 0xAA, 0xAB, 0xAC, 0xAD, 0xAE, + 0xAF, 0xB0, 0xB1, 0xB2, 0xB3, 0xB4, 0xB5, 0xB6, + 0xB7, 0xB8, 0xB9, 0xBA, 0xBB, 0xBC, 0xBD, 0xBE, + 0xBF, 0x3A, 0x00, 0x01, 0x25, 0x00, 0x58, 0x21, + 0x01, 0xFA, 0x58, 0x75, 0x5F, 0x65, 0x86, 0x27, + 0xCE, 0x54, 0x60, 0xF2, 0x9B, 0x75, 0x29, 0x67, + 0x13, 0x24, 0x8C, 0xAE, 0x7A, 0xD9, 0xE2, 0x98, + 0x4B, 0x90, 0x28, 0x0E, 0xFC, 0xBC, 0xB5, 0x02, + 0x48, 0x3A, 0x00, 0x01, 0x24, 0xFA, 0x58, 0x20, + 0xAA, 0xAA, 0xAA, 0xAA, 0xAA, 0xAA, 0xAA, 0xAA, + 0xBB, 0xBB, 0xBB, 0xBB, 0xBB, 0xBB, 0xBB, 0xBB, + 0xCC, 0xCC, 0xCC, 0xCC, 0xCC, 0xCC, 0xCC, 0xCC, + 0xDD, 0xDD, 0xDD, 0xDD, 0xDD, 0xDD, 0xDD, 0xDD, + 0x3A, 0x00, 0x01, 0x24, 0xF8, 0x20, 0x3A, 0x00, + 0x01, 0x24, 0xF9, 0x00, 0x3A, 0x00, 0x01, 0x24, + 0xFD, 0x85, 0xA5, 0x05, 0x58, 0x20, 0x00, 0x00, + 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, + 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, + 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, + 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x04, 0x60, + 0x01, 0x65, 0x42, 0x4C, 0x31, 0x5F, 0x32, 0x06, + 0x66, 0x53, 0x48, 0x41, 0x32, 0x35, 0x36, 0x02, + 0x58, 0x20, 0xF8, 0xB7, 0xCE, 0xAD, 0x9B, 0xE4, + 0x5A, 0x8F, 0x5C, 0x52, 0x6F, 0x0C, 0x05, 0x25, + 0x8F, 0xF3, 0xE9, 0x81, 0xDC, 0xBC, 0xF2, 0x05, + 0x7F, 0x33, 0xF6, 0xBB, 0xDC, 0xD9, 0x4D, 0xA2, + 0x34, 0x3A, 0xA5, 0x05, 0x58, 0x20, 0x00, 0x00, + 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, + 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, + 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, + 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x04, 0x67, + 0x31, 0x2E, 0x37, 0x2E, 0x32, 0x2B, 0x30, 0x01, + 0x63, 0x42, 0x4C, 0x32, 0x06, 0x66, 0x53, 0x48, + 0x41, 0x32, 0x35, 0x36, 0x02, 0x58, 0x20, 0x3A, + 0xE5, 0x9E, 0x40, 0xA9, 0x6B, 0xD5, 0x29, 0x1C, + 0xAB, 0x7A, 0x5F, 0xBD, 0x1F, 0x9A, 0xA6, 0x52, + 0xFB, 0x77, 0x7D, 0xA3, 0xEC, 0x9C, 0x29, 0xBC, + 0xE6, 0x5B, 0x3B, 0x43, 0xFC, 0x9D, 0x26, 0xA5, + 0x05, 0x58, 0x20, 0xBF, 0xE6, 0xD8, 0x6F, 0x88, + 0x26, 0xF4, 0xFF, 0x97, 0xFB, 0x96, 0xC4, 0xE6, + 0xFB, 0xC4, 0x99, 0x3E, 0x46, 0x19, 0xFC, 0x56, + 0x5D, 0xA2, 0x6A, 0xDF, 0x34, 0xC3, 0x29, 0x48, + 0x9A, 0xDC, 0x38, 0x04, 0x67, 0x31, 0x2E, 0x35, + 0x2E, 0x30, 0x2B, 0x30, 0x01, 0x64, 0x52, 0x54, + 0x5F, 0x30, 0x06, 0x66, 0x53, 0x48, 0x41, 0x32, + 0x35, 0x36, 0x02, 0x58, 0x20, 0x47, 0x94, 0x9D, + 0x27, 0x33, 0x82, 0x45, 0x1A, 0xDD, 0x25, 0xF4, + 0x9A, 0x89, 0x6F, 0x5F, 0xD9, 0xB0, 0xE8, 0x14, + 0xD3, 0xA4, 0x9B, 0x53, 0xB0, 0x44, 0x0B, 0xCF, + 0x32, 0x1A, 0xC4, 0xD2, 0x65, 0xA5, 0x05, 0x58, + 0x20, 0xB3, 0x60, 0xCA, 0xF5, 0xC9, 0x8C, 0x6B, + 0x94, 0x2A, 0x48, 0x82, 0xFA, 0x9D, 0x48, 0x23, + 0xEF, 0xB1, 0x66, 0xA9, 0xEF, 0x6A, 0x6E, 0x4A, + 0xA3, 0x7C, 0x19, 0x19, 0xED, 0x1F, 0xCC, 0xC0, + 0x49, 0x04, 0x67, 0x30, 0x2E, 0x30, 0x2E, 0x37, + 0x2B, 0x30, 0x01, 0x64, 0x52, 0x54, 0x5F, 0x31, + 0x06, 0x66, 0x53, 0x48, 0x41, 0x32, 0x35, 0x36, + 0x02, 0x58, 0x20, 0xCD, 0x38, 0xBE, 0xC8, 0xB7, + 0xC0, 0x9E, 0xD5, 0x24, 0x30, 0xFE, 0xC8, 0xD0, + 0x19, 0x12, 0x56, 0xB2, 0x7A, 0xA5, 0x53, 0x6F, + 0xBC, 0x7D, 0x09, 0xCA, 0x11, 0xDD, 0x90, 0xD7, + 0xD6, 0x70, 0xFD, 0xA5, 0x05, 0x58, 0x20, 0xAA, + 0xAA, 0xAA, 0xAA, 0xAA, 0xAA, 0xAA, 0xAA, 0xAA, + 0xAA, 0xAA, 0xAA, 0xAA, 0xAA, 0xAA, 0xAA, 0xAA, + 0xAA, 0xAA, 0xAA, 0xAA, 0xAA, 0xAA, 0xAA, 0xAA, + 0xAA, 0xAA, 0xAA, 0xAA, 0xAA, 0xAA, 0xAA, 0x04, + 0x60, 0x01, 0x60, 0x06, 0x66, 0x53, 0x48, 0x41, + 0x32, 0x35, 0x36, 0x02, 0x58, 0x20, 0x28, 0x3D, + 0x0C, 0x25, 0x22, 0x0C, 0x87, 0x46, 0xA0, 0x58, + 0x64, 0x6C, 0x0B, 0x14, 0x37, 0x39, 0x40, 0x9D, + 0x2D, 0x11, 0xD1, 0xCC, 0x54, 0x51, 0xB4, 0x29, + 0x22, 0xCD, 0x70, 0x92, 0x71, 0xC3, 0x3A, 0x00, + 0x01, 0x25, 0x01, 0x77, 0x77, 0x77, 0x77, 0x2E, + 0x74, 0x72, 0x75, 0x73, 0x74, 0x65, 0x64, 0x66, + 0x69, 0x72, 0x6D, 0x77, 0x61, 0x72, 0x65, 0x2E, + 0x6F, 0x72, 0x67, 0x3A, 0x00, 0x01, 0x24, 0xF7, + 0x71, 0x50, 0x53, 0x41, 0x5F, 0x49, 0x4F, 0x54, + 0x5F, 0x50, 0x52, 0x4F, 0x46, 0x49, 0x4C, 0x45, + 0x5F, 0x31, 0x3A, 0x00, 0x01, 0x24, 0xFC, 0x70, + 0x30, 0x36, 0x30, 0x34, 0x35, 0x36, 0x35, 0x32, + 0x37, 0x32, 0x38, 0x32, 0x39, 0x31, 0x30, 0x30, + 0x58, 0x40, 0x1E, 0x0D, 0x2B, 0xD8, 0x7A, 0xC9, + 0x2D, 0xCB, 0x73, 0xD1, 0x42, 0x2F, 0xBF, 0xDA, + 0x24, 0x71, 0xE2, 0xAF, 0xEA, 0x48, 0x60, 0x17, + 0x23, 0x75, 0x64, 0xAC, 0xCC, 0x23, 0xA2, 0x67, + 0xC4, 0xE7, 0x8F, 0x1C, 0x7C, 0x68, 0x49, 0x42, + 0x4D, 0xDA, 0xC6, 0xD6, 0x21, 0x1C, 0xAA, 0x00, + 0xDA, 0x1E, 0x68, 0x56, 0xA3, 0x48, 0xEE, 0xA7, + 0x92, 0xA9, 0x09, 0x83, 0x42, 0x04, 0x06, 0x9E, + 0x62, 0xBB +}; + +psa_status_t +rss_delegated_attest_get_delegated_key(uint8_t ecc_curve, + uint32_t key_bits, + uint8_t *key_buf, + size_t key_buf_size, + size_t *key_size, + uint32_t hash_algo) +{ + (void)ecc_curve; + (void)key_bits; + (void)hash_algo; + + if (key_buf_size < sizeof(delegated_key)) { + return PSA_ERROR_BUFFER_TOO_SMALL; + } + + (void)memcpy(key_buf, delegated_key, sizeof(delegated_key)); + *key_size = sizeof(delegated_key); + + return PSA_SUCCESS; +} +psa_status_t +rss_delegated_attest_get_token(const uint8_t *dak_pub_hash, + size_t dak_pub_hash_size, + uint8_t *token_buf, + size_t token_buf_size, + size_t *token_size) +{ + (void)dak_pub_hash; + (void)dak_pub_hash_size; + + if (token_buf_size < sizeof(platform_token)) { + return PSA_ERROR_BUFFER_TOO_SMALL; + } + + (void)memcpy(token_buf, platform_token, sizeof(platform_token)); + *token_size = sizeof(platform_token); + + return PSA_SUCCESS; +} +#endif /* !PLAT_RSS_NOT_SUPPORTED */ -- 2.39.5