diff --git a/docs/getting_started/porting-guide.rst b/docs/getting_started/porting-guide.rst index d935436b8..3d3b2e3e3 100644 --- a/docs/getting_started/porting-guide.rst +++ b/docs/getting_started/porting-guide.rst @@ -2043,6 +2043,32 @@ The parameters of the function are: The function returns 0 on success, -EINVAL on failure. +Function : plat_get_cca_realm_attest_key() [mandatory when ENABLE_RME == 1] +~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ + +:: + + Argument : uintptr_t, size_t *, unsigned int + Return : int + +This function returns the delegated realm attestation key which will be used to +sign Realm attestation token. The API currently only supports P-384 ECC curve +key. + +The parameters of the function are: + + arg0 - A pointer to the buffer where the attestation key should be copied + by this function. The buffer must be big enough to hold the + attestation key. + + arg1 - Contains the size (in bytes) of the buffer passed in arg0. The + function returns the attestation key length in this parameter. + + arg2 - The type of the elliptic curve to which the requested attestation key + belongs. + +The function returns 0 on success, -EINVAL on failure. + Function : bl31_plat_enable_mmu [optional] ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ @@ -3180,7 +3206,7 @@ amount of open resources per driver. -------------- -*Copyright (c) 2013-2021, Arm Limited and Contributors. All rights reserved.* +*Copyright (c) 2013-2022, Arm Limited and Contributors. All rights reserved.* .. _PSCI: http://infocenter.arm.com/help/topic/com.arm.doc.den0022c/DEN0022C_Power_State_Coordination_Interface.pdf .. _Arm Generic Interrupt Controller version 2.0 (GICv2): http://infocenter.arm.com/help/topic/com.arm.doc.ihi0048b/index.html diff --git a/include/plat/common/platform.h b/include/plat/common/platform.h index 9deb33dfd..766450901 100644 --- a/include/plat/common/platform.h +++ b/include/plat/common/platform.h @@ -307,6 +307,9 @@ plat_local_state_t plat_get_target_pwr_state(unsigned int lvl, ******************************************************************************/ int plat_get_cca_attest_token(uintptr_t buf, size_t *len, uintptr_t hash, size_t hash_size); +int plat_get_cca_realm_attest_key(uintptr_t buf, size_t *len, + unsigned int type); + /******************************************************************************* * Optional BL31 functions (may be overridden) ******************************************************************************/ diff --git a/include/services/rmmd_svc.h b/include/services/rmmd_svc.h index 9b4c39fc8..2fbdddd43 100644 --- a/include/services/rmmd_svc.h +++ b/include/services/rmmd_svc.h @@ -97,6 +97,25 @@ #define SHA384_DIGEST_SIZE 48U #define SHA512_DIGEST_SIZE 64U +/* + * Retrieve Realm attestation key from EL3. Only P-384 ECC curve key is + * supported. The arguments to this SMC are : + * arg0 - Function ID. + * arg1 - Realm attestation key buffer Physical address. + * arg2 - Realm attestation key buffer size (in bytes). + * arg3 - The type of the elliptic curve to which the requested + * attestation key belongs to. The value should be one of the + * defined curve types. + * The return arguments are : + * ret0 - Status / error. + * ret1 - Size of the realm attestation key if successful. + */ +#define RMMD_ATTEST_GET_REALM_KEY RMM_FID(SMC_64, ATTEST_GET_REALM_KEY) + +/* ECC Curve types for attest key generation */ +#define ATTEST_KEY_CURVE_ECC_SECP384R1 0 + + #ifndef __ASSEMBLER__ #include @@ -120,5 +139,4 @@ uint64_t rmmd_rmm_el3_handler(uint32_t smc_fid, uint64_t flags); #endif /* __ASSEMBLER__ */ - #endif /* RMMD_SVC_H */ diff --git a/plat/arm/board/fvp/fvp_realm_attest_key.c b/plat/arm/board/fvp/fvp_realm_attest_key.c new file mode 100644 index 000000000..b32f557f5 --- /dev/null +++ b/plat/arm/board/fvp/fvp_realm_attest_key.c @@ -0,0 +1,35 @@ +/* + * Copyright (c) 2022, ARM Limited and Contributors. All rights reserved. + * + * SPDX-License-Identifier: BSD-3-Clause + */ + +#include +#include +#include +#include +#include +#include + +static uint8_t sample_attest_priv_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 +}; + +int plat_get_cca_realm_attest_key(uintptr_t buf, size_t *len, unsigned int type) +{ + assert(type == ATTEST_KEY_CURVE_ECC_SECP384R1); + + if (*len < sizeof(sample_attest_priv_key)) { + return -EINVAL; + } + + (void)memcpy((void *)buf, sample_attest_priv_key, + sizeof(sample_attest_priv_key)); + *len = sizeof(sample_attest_priv_key); + + return 0; +} diff --git a/plat/arm/board/fvp/platform.mk b/plat/arm/board/fvp/platform.mk index 895d77309..c9f555120 100644 --- a/plat/arm/board/fvp/platform.mk +++ b/plat/arm/board/fvp/platform.mk @@ -193,7 +193,8 @@ endif ifeq (${ENABLE_RME},1) BL2_SOURCES += plat/arm/board/fvp/aarch64/fvp_helpers.S -BL31_SOURCES += plat/arm/board/fvp/fvp_plat_attest_token.c +BL31_SOURCES += plat/arm/board/fvp/fvp_plat_attest_token.c \ + plat/arm/board/fvp/fvp_realm_attest_key.c endif ifeq (${BL2_AT_EL3},1) diff --git a/services/std_svc/rmmd/rmmd_attest.c b/services/std_svc/rmmd/rmmd_attest.c index d111b88b0..0432ec3a9 100644 --- a/services/std_svc/rmmd/rmmd_attest.c +++ b/services/std_svc/rmmd/rmmd_attest.c @@ -116,3 +116,51 @@ int rmmd_attest_get_platform_token(uint64_t buf_pa, uint64_t *buf_len, uint64_t return err; } +int rmmd_attest_get_signing_key(uint64_t buf_pa, uint64_t *buf_len, + uint64_t ecc_curve) +{ + int err; + uintptr_t va; + + /* + * TODO: Currently we don't validate incoming buf_pa. This is a + * prototype and we will need to allocate static buffer for EL3-RMM + * communication. + */ + + /* We need a page of buffer to pass data */ + if (*buf_len != PAGE_SIZE) { + ERROR("Invalid buffer length\n"); + return RMMD_ERR_INVAL; + } + + if (ecc_curve != ATTEST_KEY_CURVE_ECC_SECP384R1) { + ERROR("Invalid ECC curve specified\n"); + return RMMD_ERR_INVAL; + } + + spin_lock(&lock); + + /* Map the buffer that was provided by the RMM. */ + err = mmap_add_dynamic_region_alloc_va(buf_pa, &va, PAGE_SIZE, + MT_RW_DATA | MT_REALM); + if (err != 0) { + ERROR("mmap_add_dynamic_region_alloc_va failed: %d (%p).\n" + , err, (void *)buf_pa); + spin_unlock(&lock); + return RMMD_ERR_NOMEM; + } + + /* Get the Realm attestation key. */ + err = plat_get_cca_realm_attest_key(va, buf_len, (unsigned int)ecc_curve); + if (err != 0) { + ERROR("Failed to get attestation key: %d.\n", err); + err = RMMD_ERR_UNK; + } + + /* Unmap RMM memory. */ + (void)mmap_remove_dynamic_region(va, PAGE_SIZE); + spin_unlock(&lock); + + return err; +} diff --git a/services/std_svc/rmmd/rmmd_main.c b/services/std_svc/rmmd/rmmd_main.c index c59e68a6a..cf5ff7bf4 100644 --- a/services/std_svc/rmmd/rmmd_main.c +++ b/services/std_svc/rmmd/rmmd_main.c @@ -375,6 +375,9 @@ uint64_t rmmd_rmm_el3_handler(uint32_t smc_fid, uint64_t x1, uint64_t x2, case RMMD_ATTEST_GET_PLAT_TOKEN: ret = rmmd_attest_get_platform_token(x1, &x2, x3); SMC_RET2(handle, ret, x2); + case RMMD_ATTEST_GET_REALM_KEY: + ret = rmmd_attest_get_signing_key(x1, &x2, x3); + SMC_RET2(handle, ret, x2); default: WARN("RMMD: Unsupported RMM-EL3 call 0x%08x\n", smc_fid); SMC_RET1(handle, SMC_UNK); diff --git a/services/std_svc/rmmd/rmmd_private.h b/services/std_svc/rmmd/rmmd_private.h index d7ef4e1b3..73df2b8bc 100644 --- a/services/std_svc/rmmd/rmmd_private.h +++ b/services/std_svc/rmmd/rmmd_private.h @@ -54,6 +54,8 @@ __dead2 void rmmd_rmm_sync_exit(uint64_t rc); /* Functions implementing attestation utilities for RMM */ int rmmd_attest_get_platform_token(uint64_t buf_pa, uint64_t *buf_len, uint64_t challenge_hash_len); +int rmmd_attest_get_signing_key(uint64_t buf_pa, uint64_t *buf_len, + uint64_t ecc_curve); /* Assembly helpers */ uint64_t rmmd_rmm_enter(uint64_t *c_rt_ctx);