diff options
| -rw-r--r-- | chip/g/config_chip.h | 8 | ||||
| -rw-r--r-- | chip/g/upgrade_fw.c | 3 | ||||
| -rw-r--r-- | common/ap_ro_integrity_check.c | 267 | ||||
| -rw-r--r-- | include/ap_ro_integrity_check.h | 22 | ||||
| -rw-r--r-- | include/tpm_vendor_cmds.h | 2 |
5 files changed, 300 insertions, 2 deletions
diff --git a/chip/g/config_chip.h b/chip/g/config_chip.h index 7c60567dfc..dcd85c86d1 100644 --- a/chip/g/config_chip.h +++ b/chip/g/config_chip.h @@ -160,6 +160,14 @@ (CONFIG_PROGRAM_MEMORY_BASE + CHIP_RO_B_MEM_OFF + CONFIG_RO_SIZE - \ CONFIG_FLASH_LOG_SPACE) +/* Space reserved for RO hashes */ +#define AP_RO_DATA_SPACE_SIZE CONFIG_FLASH_BANK_SIZE +#define AP_RO_DATA_SPACE_ADDR (CONFIG_FLASH_LOG_BASE - AP_RO_DATA_SPACE_SIZE) + +/* Maximum space available for the RO image */ +#define MAX_RO_CODE_SIZE (CONFIG_RO_SIZE - CONFIG_FLASH_LOG_SPACE - \ + AP_RO_DATA_SPACE_SIZE) + /* Use software crypto (libcryptoc). */ #define CONFIG_LIBCRYPTOC #endif /* __CROS_EC_CONFIG_CHIP_H */ diff --git a/chip/g/upgrade_fw.c b/chip/g/upgrade_fw.c index 727af4b7d9..f400b4f317 100644 --- a/chip/g/upgrade_fw.c +++ b/chip/g/upgrade_fw.c @@ -63,8 +63,7 @@ static void set_valid_sections(void) } valid_sections.ro_top_offset = valid_sections.ro_base_offset + - CONFIG_RO_SIZE - 0x800; /* 2K for certs! */ - + MAX_RO_CODE_SIZE; valid_sections.rw_top_offset = valid_sections.rw_base_offset + CONFIG_RW_SIZE; } diff --git a/common/ap_ro_integrity_check.c b/common/ap_ro_integrity_check.c new file mode 100644 index 0000000000..bb02f306db --- /dev/null +++ b/common/ap_ro_integrity_check.c @@ -0,0 +1,267 @@ +/* Copyright 2020 The Chromium OS Authors. All rights reserved. + * Use of this source code is governed by a BSD-style license that can be + * found in the LICENSE file. + * + * Code supporting AP RO verification. + */ + +#include "console.h" +#include "crypto_api.h" +#include "extension.h" +#include "flash.h" +#include "flash_info.h" +#include "cryptoc/sha256.h" +#include "stddef.h" +#include "stdint.h" +#include "timer.h" +#include "usb_spi.h" + +#define CPRINTS(format, args...) cprints(CC_SYSTEM, format, ##args) +#define CPRINTF(format, args...) cprintf(CC_SYSTEM, format, ##args) + +/* A flash range included in hash calculations. */ +struct flash_range { + uint32_t flash_offset; + uint32_t range_size; +} __packed; + +/* Values used for sanity check of the flash_range structure fields. */ +#define MAX_SUPPORTED_FLASH_SIZE (32 * 1024 * 1024) +#define MAX_SUPPORTED_RANGE_SIZE (4 * 1024 * 1024) + +/* Page offset for H1 flash operations. */ +static const uint32_t h1_flash_offset_ = + AP_RO_DATA_SPACE_ADDR - CONFIG_PROGRAM_MEMORY_BASE; + +/* + * Payload of the vendor command communicating a variable number of flash + * ranges to be checked and the total sha256. + * + * The actual number of ranges is determined based on the actual payload size. + */ +struct ap_ro_check_payload { + uint8_t digest[SHA256_DIGEST_SIZE]; + struct flash_range ranges[0]; +} __packed; + +/* Version of the AP RO check information saved in the H1 flash page. */ +#define AP_RO_HASH_LAYOUT_VERSION 0 + +/* + * Header added for storing of the AP RO check information in the H1 flash + * page. The checksum is a 4 byte truncated sha256 of the saved payload, just + * a sanity check. + */ +struct ap_ro_check_header { + uint16_t version; + uint16_t num_ranges; + uint32_t checksum; +}; + +/* Format of the AP RO check information saved in the H1 flash page. */ +struct ap_ro_check { + struct ap_ro_check_header header; + struct ap_ro_check_payload payload; +}; + +/* Fixed pointer at the H1 flash page storing the AP RO check information. */ +static const struct ap_ro_check *p_chk = + (const struct ap_ro_check *)AP_RO_DATA_SPACE_ADDR; + +/* Errors recognized and returned by the vendor command handler. */ +enum ap_ro_check_vc_errors { + ARCVE_TOO_SHORT = 1, + ARCVE_BAD_PAYLOAD_SIZE = 2, + ARCVE_BAD_OFFSET = 3, + ARCVE_BAD_RANGE_SIZE = 4, + ARCVE_ALREADY_PROGRAMMED = 5, +}; + +static enum vendor_cmd_rc vc_seed_ap_ro_check(enum vendor_cmd_cc code, + void *buf, size_t input_size, + size_t *response_size) +{ + struct ap_ro_check_header check_header; + const struct ap_ro_check_payload *vc_payload = buf; + uint32_t vc_num_of_ranges; + uint32_t i; + uint8_t *response = buf; + size_t prog_size; + + *response_size = 1; /* Just in case there is an error. */ + + /* There should be at least one range and the hash. */ + if (input_size < (SHA256_DIGEST_SIZE + sizeof(struct flash_range))) { + *response = ARCVE_TOO_SHORT; + return VENDOR_RC_BOGUS_ARGS; + } + + /* There should be an integer number of ranges. */ + if (((input_size - SHA256_DIGEST_SIZE) % sizeof(struct flash_range)) != + 0) { + *response = ARCVE_BAD_PAYLOAD_SIZE; + return VENDOR_RC_BOGUS_ARGS; + } + + vc_num_of_ranges = + (input_size - SHA256_DIGEST_SIZE) / sizeof(struct flash_range); + + for (i = 0; i < vc_num_of_ranges; i++) { + if (vc_payload->ranges[i].range_size > + MAX_SUPPORTED_RANGE_SIZE) { + *response = ARCVE_BAD_RANGE_SIZE; + return VENDOR_RC_BOGUS_ARGS; + } + if ((vc_payload->ranges[i].flash_offset + + vc_payload->ranges[i].range_size) > + MAX_SUPPORTED_FLASH_SIZE) { + *response = ARCVE_BAD_OFFSET; + return VENDOR_RC_BOGUS_ARGS; + } + } + + prog_size = sizeof(struct ap_ro_check_header) + input_size; + for (i = 0; i < (prog_size / sizeof(uint32_t)); i++) + if (((uint32_t *)p_chk)[i] != ~0) { + *response = ARCVE_ALREADY_PROGRAMMED; + return VENDOR_RC_NOT_ALLOWED; + } + + check_header.version = AP_RO_HASH_LAYOUT_VERSION; + check_header.num_ranges = vc_num_of_ranges; + app_compute_hash(buf, input_size, &check_header.checksum, + sizeof(check_header.checksum)); + + flash_open_ro_window(h1_flash_offset_, prog_size); + flash_physical_write(h1_flash_offset_, sizeof(check_header), + (char *)&check_header); + flash_physical_write(h1_flash_offset_ + sizeof(check_header), + input_size, buf); + + *response_size = 0; + return VENDOR_RC_SUCCESS; +} +DECLARE_VENDOR_COMMAND(VENDOR_CC_SEED_AP_RO_CHECK, vc_seed_ap_ro_check); + +static int verify_ap_ro_check_space(void) +{ + uint32_t checksum; + size_t data_size; + + data_size = p_chk->header.num_ranges * sizeof(struct flash_range) + + sizeof(struct ap_ro_check_payload); + if (data_size > CONFIG_FLASH_BANK_SIZE) { + CPRINTS("%s: bogus number of ranges %d", __func__, + p_chk->header.num_ranges); + return EC_ERROR_CRC; + } + + app_compute_hash(&p_chk->payload, data_size, &checksum, + sizeof(checksum)); + + if (memcmp(&checksum, &p_chk->header.checksum, sizeof(checksum))) { + CPRINTS("%s: AP RO Checksum corrupted", __func__); + return EC_ERROR_CRC; + } + + return EC_SUCCESS; +} + +int validate_ap_ro(void) +{ + uint32_t i; + HASH_CTX ctx; + uint8_t digest[SHA256_DIGEST_SIZE]; + int rv; + + if (p_chk->header.num_ranges == (uint16_t)~0) { + CPRINTS("%s: RO verification not programmed", __func__); + return EC_ERROR_INVAL; + } + + /* Is the contents intact? */ + if (verify_ap_ro_check_space() != EC_SUCCESS) + return EC_ERROR_INVAL; /* No verification possible. */ + + enable_ap_spi_hash_shortcut(); + usb_spi_sha256_start(&ctx); + for (i = 0; i < p_chk->header.num_ranges; i++) { + CPRINTS("%s: %x:%x", __func__, + p_chk->payload.ranges[i].flash_offset, + p_chk->payload.ranges[i].range_size); + /* Make sure the message gets out before verification starts. */ + cflush(); + usb_spi_sha256_update(&ctx, + p_chk->payload.ranges[i].flash_offset, + p_chk->payload.ranges[i].range_size); + } + + usb_spi_sha256_final(&ctx, digest, sizeof(digest)); + if (memcmp(digest, p_chk->payload.digest, sizeof(digest))) { + CPRINTS("AP RO verification FAILED!"); + CPRINTS("Calculated digest %ph", + HEX_BUF(digest, sizeof(digest))); + CPRINTS("Stored digest %ph", + HEX_BUF(p_chk->payload.digest, + sizeof(p_chk->payload.digest))); + rv = EC_ERROR_CRC; + } else { + rv = EC_SUCCESS; + CPRINTS("AP RO verification SUCCEEDED!"); + } + disable_ap_spi_hash_shortcut(); + + return rv; +} + +static int ap_ro_info_cmd(int argc, char **argv) +{ + int rv; + int i; +#ifdef CR50_DEV + int const max_args = 2; +#else + int const max_args = 1; +#endif + + if (argc > max_args) + return EC_ERROR_PARAM_COUNT; +#ifdef CR50_DEV + if (argc == max_args) { + if (strcasecmp(argv[1], "erase")) + return EC_ERROR_PARAM1; + /* + * TODO(vbendeb): Make this a partial erase, use refactored + * Board ID space partial erase. + */ + flash_open_ro_window(h1_flash_offset_, AP_RO_DATA_SPACE_SIZE); + flash_physical_erase(h1_flash_offset_, AP_RO_DATA_SPACE_SIZE); + } +#endif + if ((p_chk->header.num_ranges == (uint16_t)~0) && + (p_chk->header.checksum == ~0)) { + ccprintf("AP RO check space is not programmed\n"); + return EC_SUCCESS; + } + + rv = verify_ap_ro_check_space(); + if (rv != EC_SUCCESS) + return rv; /* No verification possible. */ + + ccprintf("sha256 hash %ph\n", + HEX_BUF(p_chk->payload.digest, sizeof(p_chk->payload.digest))); + ccprintf("Covered ranges:\n"); + for (i = 0; i < p_chk->header.num_ranges; i++) + ccprintf("%08x...%08x\n", p_chk->payload.ranges[i].flash_offset, + p_chk->payload.ranges[i].flash_offset + + p_chk->payload.ranges[i].range_size - 1); + + return EC_SUCCESS; +} +DECLARE_SAFE_CONSOLE_COMMAND(ap_ro_info, ap_ro_info_cmd, +#ifdef CR50_DEV + "[erase]", "Display or erase AP RO check space" +#else + "", "Display AP RO check space" +#endif +); diff --git a/include/ap_ro_integrity_check.h b/include/ap_ro_integrity_check.h new file mode 100644 index 0000000000..365bccbe8e --- /dev/null +++ b/include/ap_ro_integrity_check.h @@ -0,0 +1,22 @@ +/* Copyright 2020 The Chromium OS Authors. All rights reserved. + * Use of this source code is governed by a BSD-style license that can be + * found in the LICENSE file. + * + */ +#ifndef __CR50_INCLUDE_AP_RO_INTEGRITY_CHECK_H +#define __CR50_INCLUDE_AP_RO_INTEGRITY_CHECK_H + +/* + * validate_ap_ro: based on information saved in an H1 RO flash page verify + * contents of the AP flash. + * + * Returns: + * + * EC_SUCCESS if valid integrity check information was found and the AP flash + * check succeeded. + * EC_ERROR_INVAL in valid integrity check information was not found. + * EC_ERROR_CRC if information was found, but the AP flash check failed. + */ +int validate_ap_ro(void); + +#endif /* ! __CR50_INCLUDE_AP_RO_INTEGRITY_CHECK_H */ diff --git a/include/tpm_vendor_cmds.h b/include/tpm_vendor_cmds.h index 4cb3683d49..637ec05fe9 100644 --- a/include/tpm_vendor_cmds.h +++ b/include/tpm_vendor_cmds.h @@ -147,6 +147,8 @@ enum vendor_cmd_cc { VENDOR_CC_GET_BOOT_MODE = 52, VENDOR_CC_RESET_EC = 53, + VENDOR_CC_SEED_AP_RO_CHECK = 54, + LAST_VENDOR_COMMAND = 65535, }; |