diff options
Diffstat (limited to 'src/security/vboot/secdata_tpm2.c')
| -rw-r--r-- | src/security/vboot/secdata_tpm2.c | 446 |
1 files changed, 446 insertions, 0 deletions
diff --git a/src/security/vboot/secdata_tpm2.c b/src/security/vboot/secdata_tpm2.c new file mode 100644 index 0000000000..075e481435 --- /dev/null +++ b/src/security/vboot/secdata_tpm2.c @@ -0,0 +1,446 @@ +/* SPDX-License-Identifier: BSD-3-Clause */ + +#include <security/vboot/antirollback.h> +#include <security/tpm/tss.h> +#include <vb2_api.h> + +#include "secdata_tpm_private.h" + +static tpm_result_t read_space_mrc_hash(uint32_t index, uint8_t *data) +{ + RETURN_ON_FAILURE(tlcl_read(index, data, + HASH_NV_SIZE)); + return TPM_SUCCESS; +} + +/* + * This is used to initialize the TPM space for recovery hash after defining + * it. Since there is no data available to calculate hash at the point where TPM + * space is defined, initialize it to all 0s. + */ +static const uint8_t mrc_hash_data[HASH_NV_SIZE] = { }; + +/* + * Different sets of NVRAM space attributes apply to the "ro" spaces, + * i.e. those which should not be possible to delete or modify once + * the RO exits, and the rest of the NVRAM spaces. + */ +static const TPMA_NV ro_space_attributes = { + .TPMA_NV_PPWRITE = 1, + .TPMA_NV_AUTHREAD = 1, + .TPMA_NV_PPREAD = 1, + .TPMA_NV_PLATFORMCREATE = 1, + .TPMA_NV_WRITE_STCLEAR = 1, + .TPMA_NV_POLICY_DELETE = 1, +}; + +static const TPMA_NV rw_space_attributes = { + .TPMA_NV_PPWRITE = 1, + .TPMA_NV_AUTHREAD = 1, + .TPMA_NV_PPREAD = 1, + .TPMA_NV_PLATFORMCREATE = 1, + .TPMA_NV_WRITE_STCLEAR = 1, +}; + +static const TPMA_NV rw_auth_space_attributes = { + .TPMA_NV_AUTHWRITE = 1, + .TPMA_NV_AUTHREAD = 1, + .TPMA_NV_NO_DA = 1, + .TPMA_NV_PPREAD = 1, + .TPMA_NV_PPWRITE = 1, + .TPMA_NV_PLATFORMCREATE = 1, + .TPMA_NV_WRITE_STCLEAR = 1, + .TPMA_NV_POLICY_DELETE = 1, +}; + +static const TPMA_NV fwmp_attr = { + .TPMA_NV_PLATFORMCREATE = 1, + .TPMA_NV_OWNERWRITE = 1, + .TPMA_NV_AUTHREAD = 1, + .TPMA_NV_PPREAD = 1, + .TPMA_NV_PPWRITE = 1, +}; + +/* Attributes for spaces that enable zero-touch enrollment (ZTE) */ +static const TPMA_NV zte_attr = { + .TPMA_NV_PLATFORMCREATE = 1, + .TPMA_NV_WRITEDEFINE = 1, + .TPMA_NV_AUTHWRITE = 1, + .TPMA_NV_AUTHREAD = 1, + .TPMA_NV_PPWRITE = 1, + .TPMA_NV_PPREAD = 1, + .TPMA_NV_NO_DA = 1, + .TPMA_NV_POLICY_DELETE = 1, +}; + +static const TPMA_NV zte_rma_bytes_attr = { + .TPMA_NV_PLATFORMCREATE = 1, + .TPMA_NV_BITS = 1, + .TPMA_NV_AUTHWRITE = 1, + .TPMA_NV_AUTHREAD = 1, + .TPMA_NV_PPWRITE = 1, + .TPMA_NV_PPREAD = 1, + .TPMA_NV_NO_DA = 1, + .TPMA_NV_POLICY_DELETE = 1, +}; + +static const TPMA_NV rw_orderly_counter_attributes = { + .TPMA_NV_COUNTER = 1, + .TPMA_NV_ORDERLY = 1, + .TPMA_NV_AUTHREAD = 1, + .TPMA_NV_AUTHWRITE = 1, + .TPMA_NV_PLATFORMCREATE = 1, + .TPMA_NV_WRITE_STCLEAR = 1, + .TPMA_NV_PPREAD = 1, + .TPMA_NV_PPWRITE = 1, + .TPMA_NV_NO_DA = 1, +}; + +/* + * This policy digest was obtained using TPM2_PolicyOR on 3 digests + * corresponding to a sequence of + * -) TPM2_PolicyCommandCode(TPM_CC_NV_UndefineSpaceSpecial), + * -) TPM2_PolicyPCR(PCR0, <extended_value>). + * where <extended value> is + * 1) all zeros = initial, unextended state: + * - Value to extend to initial PCR0: + * <none> + * - Resulting PCR0: + * 0000000000000000000000000000000000000000000000000000000000000000 + * - Policy digest for PolicyCommandCode + PolicyPCR: + * 4B44FC4192DB5AD7167E0135708FD374890A06BFB56317DF01F24F2226542A3F + * 2) result of extending (SHA1(0x00|0x01|0x00) | 00s to SHA256 size) + * - Value to extend to initial PCR0: + * 62571891215b4efc1ceab744ce59dd0b66ea6f73000000000000000000000000 + * - Resulting PCR0: + * 9F9EA866D3F34FE3A3112AE9CB1FBABC6FFE8CD261D42493BC6842A9E4F93B3D + * - Policy digest for PolicyCommandCode + PolicyPCR: + * CB5C8014E27A5F7586AAE42DB4F9776A977BCBC952CA61E33609DA2B2C329418 + * 3) result of extending (SHA1(0x01|0x01|0x00) | 00s to SHA256 size) + * - Value to extend to initial PCR0: + * 47ec8d98366433dc002e7721c9e37d5067547937000000000000000000000000 + * - Resulting PCR0: + * 2A7580E5DA289546F4D2E0509CC6DE155EA131818954D36D49E027FD42B8C8F8 + * - Policy digest for PolicyCommandCode + PolicyPCR: + * E6EF4F0296AC3EF0F53906480985B1BE8058E0E517E5F74A5B8A415EFE339D87 + * Values #2 and #3 correspond to two forms of recovery mode as extended by + * vb2api_get_pcr_digest(). + * As a result, the digest allows deleting the space with UndefineSpaceSpecial + * at early RO stages (before extending PCR0) or from recovery mode. + */ +static const uint8_t pcr0_allowed_policy[] = { + 0x44, 0x44, 0x79, 0x00, 0xCB, 0xB8, 0x3F, 0x5B, 0x15, 0x76, 0x56, + 0x50, 0xEF, 0x96, 0x98, 0x0A, 0x2B, 0x96, 0x6E, 0xA9, 0x09, 0x04, + 0x4A, 0x01, 0xB8, 0x5F, 0xA5, 0x4A, 0x96, 0xFC, 0x59, 0x84}; + +static const uint8_t unsatisfiable_policy[VB2_SHA256_DIGEST_SIZE] = + "hmwhat if RBR beat merc in 2021"; + +static uint32_t define_space(const char *name, uint32_t index, uint32_t length, + const TPMA_NV nv_attributes, + const uint8_t *nv_policy, size_t nv_policy_size) +{ + tpm_result_t rc; + + rc = tlcl2_define_space(index, length, nv_attributes, nv_policy, nv_policy_size); + if (rc == TPM_CB_NV_DEFINED) { + /* + * Continue with writing: it may be defined, but not written + * to. In that case a subsequent tlcl_read() would still return + * TPM_BADINDEX on TPM 2.0. The cases when some non-firmware + * space is defined while the firmware space is not there + * should be rare (interrupted initialization), so no big harm + * in writing once again even if it was written already. + */ + VBDEBUG("%s: %s space already exists\n", __func__, name); + rc = TPM_SUCCESS; + } + + return rc; +} + +static tpm_result_t setup_space(const char *name, uint32_t index, const void *data, + uint32_t length, const TPMA_NV nv_attributes, + const uint8_t *nv_policy, size_t nv_policy_size) +{ + tpm_result_t rc; + + rc = define_space(name, index, length, nv_attributes, nv_policy, + nv_policy_size); + if (rc != TPM_SUCCESS) + return rc; + + return safe_write(index, data, length); +} + +static tpm_result_t setup_firmware_space(struct vb2_context *ctx) +{ + uint32_t firmware_space_size = vb2api_secdata_firmware_create(ctx); + + return setup_space("firmware", FIRMWARE_NV_INDEX, + ctx->secdata_firmware, firmware_space_size, + ro_space_attributes, pcr0_allowed_policy, + sizeof(pcr0_allowed_policy)); +} + +static tpm_result_t setup_fwmp_space(struct vb2_context *ctx) +{ + uint32_t fwmp_space_size = vb2api_secdata_fwmp_create(ctx); + + return setup_space("FWMP", FWMP_NV_INDEX, ctx->secdata_fwmp, fwmp_space_size, + fwmp_attr, NULL, 0); +} + +static tpm_result_t setup_kernel_space(struct vb2_context *ctx) +{ + uint32_t kernel_space_size = vb2api_secdata_kernel_create(ctx); + + return setup_space("kernel", KERNEL_NV_INDEX, ctx->secdata_kernel, + kernel_space_size, rw_space_attributes, NULL, 0); +} + +static tpm_result_t set_mrc_hash_space(uint32_t index, const uint8_t *data) +{ + if (index == MRC_REC_HASH_NV_INDEX) { + return setup_space("RO MRC Hash", index, data, HASH_NV_SIZE, + ro_space_attributes, pcr0_allowed_policy, + sizeof(pcr0_allowed_policy)); + } else { + return setup_space("RW MRC Hash", index, data, HASH_NV_SIZE, + rw_space_attributes, NULL, 0); + } +} + +/** + * Set up the Zero-Touch Enrollment(ZTE) related spaces. + * + * These spaces are not used by firmware, but we do need to initialize them. + */ +static tpm_result_t setup_zte_spaces(void) +{ + tpm_result_t rc; + uint64_t rma_bytes_counter_default = 0; + uint8_t rma_sn_bits_default[16]; + uint8_t board_id_default[12]; + + /* Initialize defaults: Board ID and RMA+SN Bits must be initialized + to all 0xFFs. */ + memset(rma_sn_bits_default, 0xFF, ARRAY_SIZE(rma_sn_bits_default)); + memset(board_id_default, 0xFF, ARRAY_SIZE(board_id_default)); + + /* Set up RMA + SN Bits */ + rc = setup_space("RMA + SN Bits", ZTE_RMA_SN_BITS_INDEX, + rma_sn_bits_default, sizeof(rma_sn_bits_default), + zte_attr, + unsatisfiable_policy, sizeof(unsatisfiable_policy)); + if (rc != TPM_SUCCESS) { + VBDEBUG("%s: Failed to set up RMA + SN Bits space with error %#x\n", __func__, rc); + return rc; + } + + rc = setup_space("Board ID", ZTE_BOARD_ID_NV_INDEX, + board_id_default, sizeof(board_id_default), + zte_attr, + unsatisfiable_policy, sizeof(unsatisfiable_policy)); + if (rc != TPM_SUCCESS) { + VBDEBUG("%s: Failed to set up Board ID space with error %#x\n", __func__, rc); + return rc; + } + + /* Set up RMA Bytes counter */ + rc = define_space("RMA Bytes Counter", ZTE_RMA_BYTES_COUNTER_INDEX, + sizeof(rma_bytes_counter_default), + zte_rma_bytes_attr, + unsatisfiable_policy, sizeof(unsatisfiable_policy)); + if (rc != TPM_SUCCESS) { + VBDEBUG("%s: Failed to define RMA Bytes space with error %#x\n", __func__, rc); + return rc; + } + + /* + * Since the RMA counter has the BITS attribute, we need to call + * TPM2_NV_SetBits() in order to initialize it. + */ + rc = tlcl2_set_bits(ZTE_RMA_BYTES_COUNTER_INDEX, rma_bytes_counter_default); + if (rc != TPM_SUCCESS) { + VBDEBUG("%s: Failed to init RMA Bytes counter space wit error %#x\n", + __func__, rc); + return rc; + } + + return rc; +} + +/* + * Set up enterprise rollback space. + * + * This space is not used by firmware but needs to survive owner clear. Thus, it + * needs to be created here. + */ +static tpm_result_t enterprise_rollback_create_space(void) +{ + uint8_t rollback_space_default[32] = {0}; + + return setup_space("Enterprise Rollback Space", + ENT_ROLLBACK_SPACE_INDEX, rollback_space_default, + sizeof(rollback_space_default), rw_auth_space_attributes, + unsatisfiable_policy, sizeof(unsatisfiable_policy)); +} + +static tpm_result_t setup_widevine_counter_spaces(void) +{ + uint32_t index; + tpm_result_t rc; + + for (index = 0; index < NUM_WIDEVINE_COUNTERS; index++) { + rc = define_space(WIDEVINE_COUNTER_NAME, + WIDEVINE_COUNTER_NV_INDEX(index), + WIDEVINE_COUNTER_SIZE, + rw_orderly_counter_attributes, + NULL, + 0); + if (rc != TPM_SUCCESS) + return rc; + } + return rc; +} + +tpm_result_t factory_initialize_tpm2(struct vb2_context *ctx) +{ + RETURN_ON_FAILURE(tlcl_force_clear()); + + /* + * Of all NVRAM spaces defined by this function the firmware space + * must be defined last, because its existence is considered an + * indication that TPM factory initialization was successfully + * completed. + */ + RETURN_ON_FAILURE(setup_kernel_space(ctx)); + + /* + * Define and set rec hash space, if available. No need to + * create the RW hash space because we will definitely boot + * once in normal mode before shipping, meaning that the space + * will get created with correct permissions while still in + * our hands. + */ + if (CONFIG(VBOOT_HAS_REC_HASH_SPACE)) + RETURN_ON_FAILURE(set_mrc_hash_space(MRC_REC_HASH_NV_INDEX, mrc_hash_data)); + + /* Define and write firmware management parameters space. */ + RETURN_ON_FAILURE(setup_fwmp_space(ctx)); + + /* + * Define and write zero-touch enrollment (ZTE) spaces. For ChromeOS devices with + * Google TPM, these are set up elsewhere via TPM vendor commands. + */ + if (CONFIG(CHROMEOS) && !(CONFIG(TPM_GOOGLE))) + RETURN_ON_FAILURE(setup_zte_spaces()); + + /* + * On TPM 2.0, create a space that survives TPM clear. This allows to + * securely lock data during enterprise rollback by binding to this + * space's value. + */ + if (CONFIG(CHROMEOS)) + RETURN_ON_FAILURE(enterprise_rollback_create_space()); + + /* Define widevine counter space. No need to increment/write to the secure counters + and are expected to be incremented during the first use. */ + if (CONFIG(VBOOT_DEFINE_WIDEVINE_COUNTERS)) + RETURN_ON_FAILURE(setup_widevine_counter_spaces()); + + RETURN_ON_FAILURE(setup_firmware_space(ctx)); + + return TPM_SUCCESS; +} + +tpm_result_t antirollback_read_space_mrc_hash(uint32_t index, uint8_t *data, uint32_t size) +{ + if (size != HASH_NV_SIZE) { + VBDEBUG("TPM: Incorrect buffer size for hash idx %#x. " + "(Expected=%#x Actual=%#x).\n", index, HASH_NV_SIZE, + size); + return TPM_CB_READ_FAILURE; + } + return read_space_mrc_hash(index, data); +} + +tpm_result_t antirollback_write_space_mrc_hash(uint32_t index, const uint8_t *data, uint32_t size) +{ + uint8_t spc_data[HASH_NV_SIZE]; + tpm_result_t rc; + + if (size != HASH_NV_SIZE) { + VBDEBUG("TPM: Incorrect buffer size for hash idx %#x. " + "(Expected=%#x Actual=%#x).\n", index, HASH_NV_SIZE, + size); + return TPM_CB_WRITE_FAILURE; + } + + rc = read_space_mrc_hash(index, spc_data); + if (rc == TPM_BADINDEX) { + /* + * If space is not defined already for hash, define + * new space. + */ + VBDEBUG("TPM: Initializing hash space.\n"); + return set_mrc_hash_space(index, data); + } + + if (rc != TPM_SUCCESS) + return rc; + + return safe_write(index, data, size); +} + +tpm_result_t antirollback_lock_space_mrc_hash(uint32_t index) +{ + return tlcl2_lock_nv_write(index); +} + +static tpm_result_t read_space_vbios_hash(uint8_t *data) +{ + RETURN_ON_FAILURE(tlcl_read(VBIOS_CACHE_NV_INDEX, data, HASH_NV_SIZE)); + return TPM_SUCCESS; +} + +tpm_result_t antirollback_read_space_vbios_hash(uint8_t *data, uint32_t size) +{ + if (size != HASH_NV_SIZE) { + VBDEBUG("TPM: Incorrect buffer size for hash idx %#x. " + "(Expected=%#x Actual=%#x).\n", VBIOS_CACHE_NV_INDEX, HASH_NV_SIZE, + size); + return TPM_CB_READ_FAILURE; + } + return read_space_vbios_hash(data); +} + +tpm_result_t antirollback_write_space_vbios_hash(const uint8_t *data, uint32_t size) +{ + uint8_t spc_data[HASH_NV_SIZE]; + tpm_result_t rc; + + if (size != HASH_NV_SIZE) { + VBDEBUG("TPM: Incorrect buffer size for hash idx %#x. " + "(Expected=%#x Actual=%#x).\n", VBIOS_CACHE_NV_INDEX, HASH_NV_SIZE, + size); + return TPM_CB_WRITE_FAILURE; + } + + rc = read_space_vbios_hash(spc_data); + if (rc == TPM_BADINDEX) { + /* + * If space is not defined already for hash, define + * new space. + */ + VBDEBUG("TPM: Initializing hash space.\n"); + return setup_space("VBIOS Cache Hash", VBIOS_CACHE_NV_INDEX, data, HASH_NV_SIZE, + rw_space_attributes, NULL, 0); + } + + if (rc != TPM_SUCCESS) + return rc; + + return safe_write(VBIOS_CACHE_NV_INDEX, data, size); +} |