diff options
Diffstat (limited to 'firmware/lib/vboot_api_kernel.c')
| -rw-r--r-- | firmware/lib/vboot_api_kernel.c | 98 |
1 files changed, 79 insertions, 19 deletions
diff --git a/firmware/lib/vboot_api_kernel.c b/firmware/lib/vboot_api_kernel.c index 3a385d2d..c7213ede 100644 --- a/firmware/lib/vboot_api_kernel.c +++ b/firmware/lib/vboot_api_kernel.c @@ -555,12 +555,14 @@ VbError_t VbEcSoftwareSync(VbCommonParams *cparams) (VbSharedDataHeader *)cparams->shared_data_blob; int in_rw = 0; int rv; - const uint8_t *ec_hash; + const uint8_t *ec_hash = NULL; int ec_hash_size; - const uint8_t *expected; + const uint8_t *rw_hash = NULL; + int rw_hash_size; + const uint8_t *expected = NULL; int expected_size; uint8_t expected_hash[SHA256_DIGEST_SIZE]; - int need_update; + int need_update = 0; int i; /* Determine whether the EC is in RO or RW */ @@ -660,29 +662,87 @@ VbError_t VbEcSoftwareSync(VbCommonParams *cparams) VBDEBUG(("\n")); /* - * Get expected EC-RW code. Note that we've already checked for + * Get expected EC-RW hash. Note that we've already checked for * RO_NORMAL, so we know that the BIOS must be RW-A or RW-B, and * therefore the EC must match. */ - rv = VbExEcGetExpectedRW(shared->firmware_index ? + rv = VbExEcGetExpectedRWHash(shared->firmware_index ? VB_SELECT_FIRMWARE_B : VB_SELECT_FIRMWARE_A, - &expected, &expected_size); - if (rv) { + &rw_hash, &rw_hash_size); + + if (rv == VBERROR_EC_GET_EXPECTED_HASH_FROM_IMAGE) { + /* + * BIOS has verified EC image but doesn't have a precomputed + * hash for it, so we must compute the hash ourselves. + */ + rw_hash = NULL; + } else if (rv) { VBDEBUG(("VbEcSoftwareSync() - " - "VbExEcGetExpectedRW() returned %d\n", rv)); - VbSetRecoveryRequest(VBNV_RECOVERY_EC_EXPECTED_IMAGE); + "VbExEcGetExpectedRWHash() returned %d\n", rv)); + VbSetRecoveryRequest(VBNV_RECOVERY_EC_EXPECTED_HASH); + return VBERROR_EC_REBOOT_TO_RO_REQUIRED; + } else if (rw_hash_size != SHA256_DIGEST_SIZE) { + VBDEBUG(("VbEcSoftwareSync() - " + "VbExEcGetExpectedRWHash() says size %d, not %d\n", + rw_hash_size, SHA256_DIGEST_SIZE)); + VbSetRecoveryRequest(VBNV_RECOVERY_EC_EXPECTED_HASH); return VBERROR_EC_REBOOT_TO_RO_REQUIRED; + } else { + VBDEBUG(("Expected hash:")); + for (i = 0; i < SHA256_DIGEST_SIZE; i++) + VBDEBUG(("%02x", rw_hash[i])); + VBDEBUG(("\n")); + + need_update = SafeMemcmp(ec_hash, rw_hash, SHA256_DIGEST_SIZE); } - VBDEBUG(("VbEcSoftwareSync() - expected len = %d\n", expected_size)); - /* Hash expected code */ - internal_SHA256(expected, expected_size, expected_hash); - VBDEBUG(("Expected hash:")); - for (i = 0; i < SHA256_DIGEST_SIZE; i++) - VBDEBUG(("%02x", expected_hash[i])); - VBDEBUG(("\n")); + /* + * Get expected EC-RW image if we're sure we need to update (because the + * expected hash didn't match the EC) or we still don't know (because + * there was no expected hash and we need the image to compute one + * ourselves). + */ + if (need_update || !rw_hash) { + /* Get expected EC-RW image */ + rv = VbExEcGetExpectedRW(shared->firmware_index ? + VB_SELECT_FIRMWARE_B : + VB_SELECT_FIRMWARE_A, + &expected, &expected_size); + if (rv) { + VBDEBUG(("VbEcSoftwareSync() - " + "VbExEcGetExpectedRW() returned %d\n", rv)); + VbSetRecoveryRequest(VBNV_RECOVERY_EC_EXPECTED_IMAGE); + return VBERROR_EC_REBOOT_TO_RO_REQUIRED; + } + VBDEBUG(("VbEcSoftwareSync() - expected len = %d\n", + expected_size)); + + /* Hash expected image */ + internal_SHA256(expected, expected_size, expected_hash); + VBDEBUG(("Computed hash of expected image:")); + for (i = 0; i < SHA256_DIGEST_SIZE; i++) + VBDEBUG(("%02x", expected_hash[i])); + VBDEBUG(("\n")); + } - need_update = SafeMemcmp(ec_hash, expected_hash, SHA256_DIGEST_SIZE); + if (!rw_hash) { + /* + * BIOS didn't have expected EC hash, so check if we need + * update by comparing EC hash to the one we just computed. + */ + need_update = SafeMemcmp(ec_hash, expected_hash, + SHA256_DIGEST_SIZE); + } else if (need_update && + SafeMemcmp(rw_hash, expected_hash, SHA256_DIGEST_SIZE)) { + /* + * We need to update, but the expected EC image doesn't match + * the expected EC hash we were given. + */ + VBDEBUG(("VbEcSoftwareSync() - " + "VbExEcGetExpectedRW() returned %d\n", rv)); + VbSetRecoveryRequest(VBNV_RECOVERY_EC_HASH_MISMATCH); + return VBERROR_EC_REBOOT_TO_RO_REQUIRED; + } /* * TODO: GBB flag to override whether we need update; needed for EC @@ -692,7 +752,7 @@ VbError_t VbEcSoftwareSync(VbCommonParams *cparams) if (in_rw) { if (need_update) { /* - * EC is running the wrong RW code. Reboot the EC to + * EC is running the wrong RW image. Reboot the EC to * RO so we can update it on the next boot. */ VBDEBUG(("VbEcSoftwareSync() - " @@ -747,7 +807,7 @@ VbError_t VbEcSoftwareSync(VbCommonParams *cparams) if (rv != VBERROR_SUCCESS) return rv; - /* Tell EC to jump to its RW code */ + /* Tell EC to jump to its RW image */ VBDEBUG(("VbEcSoftwareSync() jumping to EC-RW\n")); rv = VbExEcJumpToRW(); if (rv != VBERROR_SUCCESS) { |