Hi Ruchika, On Wed, 24 Nov 2021 at 18:12, Ruchika Gupta <ruchika.gu...@linaro.org> wrote: > > Hi Kojima-san, > > On Wed, 24 Nov 2021 at 13:08, Masahisa Kojima <masahisa.koj...@linaro.org> > wrote: >> >> Hi Ruchika, Ilias, >> >> On Tue, 23 Nov 2021 at 20:53, Ruchika Gupta <ruchika.gu...@linaro.org> wrote: >> > >> > Platforms may have support to measure their initial firmware components >> > and pass the event log to u-boot. The event log address can be passed >> > in property tpm_event_log_addr and tpm_event_log_size of the tpm node. >> > Platforms may choose their own specific mechanism to do so. A weak >> > function is added to check if even log has been passed to u-boot >> > from earlier firmware components. If available, the eventlog is parsed >> > to check for its correctness and further event logs are appended to the >> > passed log. >> >> It implies that U-Boot is no longer s-crtm, so existing >> efi_append_scrtm_version() >> call shall be skipped in this case. > > > Thanks for bringing this up. Is this a required event ? I don't see the TF-A > appending this event to the log currently. I will need to go and check the > spec for this.
Yes, TCG PC Client Platform Firmware Profile Specification[*1] page 29 says the following item must be measured. --- 3. The SRTM’s version identifier, using the event type EV_S_CRTM_VERSION. See Section 10.4.1 Event Types. --- [*1] https://trustedcomputinggroup.org/resource/pc-client-specific-platform-firmware-profile-specification/ Thanks, Masahisa Kojima > > Regards, > Ruchika > >> >> >> Thanks, >> Masahisa Kojima >> >> > >> > Signed-off-by: Ruchika Gupta <ruchika.gu...@linaro.org> >> > --- >> > v2: >> > Moved firmware eventlog code parsing to tcg2_get_fw_eventlog() >> > >> > lib/efi_loader/efi_tcg2.c | 322 ++++++++++++++++++++++++++++++++++++-- >> > 1 file changed, 308 insertions(+), 14 deletions(-) >> > >> > diff --git a/lib/efi_loader/efi_tcg2.c b/lib/efi_loader/efi_tcg2.c >> > index 8c1f22e337..c3ebdf92f5 100644 >> > --- a/lib/efi_loader/efi_tcg2.c >> > +++ b/lib/efi_loader/efi_tcg2.c >> > @@ -324,6 +324,45 @@ __weak efi_status_t platform_get_tpm2_device(struct >> > udevice **dev) >> > return EFI_NOT_FOUND; >> > } >> > >> > +/** >> > + * platform_get_eventlog() - retrieve the eventlog address and size >> > + * >> > + * This function retrieves the eventlog address and size if the underlying >> > + * firmware has done some measurements and passed them. >> > + * >> > + * This function may be overridden based on platform specific method of >> > + * passing the eventlog address and size. >> > + * >> > + * @dev: udevice >> > + * @addr: eventlog address >> > + * @sz: eventlog size >> > + * Return: status code >> > + */ >> > +__weak efi_status_t platform_get_eventlog(struct udevice *dev, u64 *addr, >> > + u32 *sz) >> > +{ >> > + const u64 *basep; >> > + const u32 *sizep; >> > + >> > + basep = dev_read_prop(dev, "tpm_event_log_addr", NULL); >> > + if (!basep) >> > + return EFI_NOT_FOUND; >> > + >> > + *addr = be64_to_cpup((__force __be64 *)basep); >> > + >> > + sizep = dev_read_prop(dev, "tpm_event_log_size", NULL); >> > + if (!sizep) >> > + return EFI_NOT_FOUND; >> > + >> > + *sz = be32_to_cpup((__force __be32 *)sizep); >> > + if (*sz == 0) { >> > + log_debug("event log empty\n"); >> > + return EFI_NOT_FOUND; >> > + } >> > + >> > + return EFI_SUCCESS; >> > +} >> > + >> > /** >> > * tpm2_get_max_command_size() - get the supported max command size >> > * >> > @@ -1181,6 +1220,249 @@ static const struct efi_tcg2_protocol >> > efi_tcg2_protocol = { >> > .get_result_of_set_active_pcr_banks = >> > efi_tcg2_get_result_of_set_active_pcr_banks, >> > }; >> > >> > +/** >> > + * parse_event_log_header() - Parse and verify the event log header >> > fields >> > + * >> > + * @buffer: Pointer to the event header >> > + * @size: Size of the eventlog >> > + * @pos: Position in buffer after event log header >> > + * >> > + * Return: status code >> > + */ >> > +efi_status_t parse_event_log_header(void *buffer, u32 size, u32 *pos) >> > +{ >> > + struct tcg_pcr_event *event_header = (struct tcg_pcr_event >> > *)buffer; >> > + int i = 0; >> > + >> > + if (size < sizeof(*event_header)) >> > + return EFI_COMPROMISED_DATA; >> > + >> > + if (get_unaligned_le32(&event_header->pcr_index) != 0 || >> > + get_unaligned_le32(&event_header->event_type) != EV_NO_ACTION) >> > + return EFI_COMPROMISED_DATA; >> > + >> > + for (i = 0; i < sizeof(event_header->digest); i++) { >> > + if (event_header->digest[i] != 0) >> > + return EFI_COMPROMISED_DATA; >> > + } >> > + >> > + *pos += sizeof(*event_header); >> > + >> > + return EFI_SUCCESS; >> > +} >> > + >> > +/** >> > + * parse_specid_event() - Parse and verify the specID Event in the >> > eventlog >> > + * >> > + * @dev: udevice >> > + * @buffer: Pointer to the start of the eventlog >> > + * @log_size: Size of the eventlog >> > + * @pos: Offset in the evenlog where specID event starts >> > + * >> > + * Return: status code >> > + * @pos Offset in the eventlog where the specID >> > event ends >> > + * @digest_list: list of digests in the event >> > + */ >> > +efi_status_t parse_specid_event(struct udevice *dev, void *buffer, u32 >> > log_size, >> > + u32 *pos, >> > + struct tpml_digest_values *digest_list) >> > +{ >> > + struct tcg_efi_spec_id_event *spec_event; >> > + struct tcg_pcr_event *event_header = (struct tcg_pcr_event >> > *)buffer; >> > + size_t spec_event_size; >> > + u32 active = 0, supported = 0, pcr_count = 0, alg_count = 0; >> > + u32 spec_active = 0; >> > + u16 hash_alg, hash_sz; >> > + u8 vendor_sz; >> > + int err, i; >> > + >> > + /* Check specID event data */ >> > + spec_event = (struct tcg_efi_spec_id_event *)((uintptr_t)buffer + >> > *pos); >> > + /* Check for signature */ >> > + if (memcmp(spec_event->signature, >> > TCG_EFI_SPEC_ID_EVENT_SIGNATURE_03, >> > + sizeof(TCG_EFI_SPEC_ID_EVENT_SIGNATURE_03))) { >> > + log_err("specID Event: Signature mismatch\n"); >> > + return EFI_COMPROMISED_DATA; >> > + } >> > + >> > + if (spec_event->spec_version_minor != >> > + TCG_EFI_SPEC_ID_EVENT_SPEC_VERSION_MINOR_TPM2 || >> > + spec_event->spec_version_major != >> > + TCG_EFI_SPEC_ID_EVENT_SPEC_VERSION_MAJOR_TPM2) >> > + return EFI_COMPROMISED_DATA; >> > + >> > + if (spec_event->number_of_algorithms > MAX_HASH_COUNT || >> > + spec_event->number_of_algorithms < 1) { >> > + log_err("specID Event: Number of algorithms incorrect\n"); >> > + return EFI_COMPROMISED_DATA; >> > + } >> > + >> > + alg_count = spec_event->number_of_algorithms; >> > + >> > + err = tpm2_get_pcr_info(dev, &supported, &active, &pcr_count); >> > + if (err) >> > + return EFI_DEVICE_ERROR; >> > + >> > + digest_list->count = 0; >> > + /* >> > + * We may need to worry about the order of algs in this structure >> > as >> > + * subsequent entries in event should be in same order >> > + */ >> > + for (i = 0; i < alg_count; i++) { >> > + hash_alg = >> > + >> > get_unaligned_le16(&spec_event->digest_sizes[i].algorithm_id); >> > + hash_sz = >> > + >> > get_unaligned_le16(&spec_event->digest_sizes[i].digest_size); >> > + >> > + if (!(supported & alg_to_mask(hash_alg))) { >> > + log_err("specID Event: Unsupported algorithm\n"); >> > + return EFI_COMPROMISED_DATA; >> > + } >> > + digest_list->digests[digest_list->count++].hash_alg = >> > hash_alg; >> > + >> > + spec_active |= alg_to_mask(hash_alg); >> > + } >> > + >> > + /* TCG spec expects the event log to have hashes for all active >> > PCR's */ >> > + if (spec_active != active) { >> > + /* >> > + * Previous stage bootloader should know all the active >> > PCR's >> > + * and use them in the Eventlog. >> > + */ >> > + log_err("specID Event: All active hash alg not present\n"); >> > + return EFI_COMPROMISED_DATA; >> > + } >> > + >> > + /* >> > + * the size of the spec event and placement of vendor_info_size >> > + * depends on supported algoriths >> > + */ >> > + spec_event_size = >> > + offsetof(struct tcg_efi_spec_id_event, digest_sizes) + >> > + alg_count * sizeof(spec_event->digest_sizes[0]); >> > + >> > + vendor_sz = *(uint8_t *)((uintptr_t)buffer + *pos + >> > spec_event_size); >> > + >> > + spec_event_size += sizeof(vendor_sz) + vendor_sz; >> > + *pos += spec_event_size; >> > + >> > + if (get_unaligned_le32(&event_header->event_size) != >> > spec_event_size) { >> > + log_err("specID event: header event size mismatch\n"); >> > + /* Right way to handle this can be to call SetActive PCR's >> > */ >> > + return EFI_COMPROMISED_DATA; >> > + } >> > + >> > + return EFI_SUCCESS; >> > +} >> > + >> > +efi_status_t tcg2_parse_event(struct udevice *dev, void *buffer, u32 >> > log_size, >> > + u32 *offset, struct tpml_digest_values >> > *digest_list, >> > + u32 *pcr) >> > +{ >> > + struct tcg_pcr_event2 *event = NULL; >> > + u32 event_type, count, size, event_size; >> > + size_t pos; >> > + >> > + if (*offset > log_size) >> > + return EFI_COMPROMISED_DATA; >> > + >> > + event = (struct tcg_pcr_event2 *)((uintptr_t)buffer + *offset); >> > + >> > + *pcr = get_unaligned_le32(&event->pcr_index); >> > + >> > + event_size = tcg_event_final_size(digest_list); >> > + >> > + if (*offset + event_size > log_size) { >> > + log_err("Event exceeds log size\n"); >> > + return EFI_COMPROMISED_DATA; >> > + } >> > + >> > + event_type = get_unaligned_le32(&event->event_type); >> > + >> > + /* get the count */ >> > + count = get_unaligned_le32(&event->digests.count); >> > + if (count != digest_list->count) >> > + return EFI_COMPROMISED_DATA; >> > + >> > + pos = offsetof(struct tcg_pcr_event2, digests); >> > + pos += offsetof(struct tpml_digest_values, digests); >> > + >> > + for (int i = 0; i < digest_list->count; i++) { >> > + u16 alg; >> > + u16 hash_alg = digest_list->digests[i].hash_alg; >> > + u8 *digest = (u8 *)&digest_list->digests[i].digest; >> > + >> > + alg = get_unaligned_le16((void *)((uintptr_t)event + pos)); >> > + >> > + if (alg != hash_alg) >> > + return EFI_COMPROMISED_DATA; >> > + >> > + pos += offsetof(struct tpmt_ha, digest); >> > + memcpy(digest, (void *)((uintptr_t)event + pos), >> > alg_to_len(hash_alg)); >> > + pos += alg_to_len(hash_alg); >> > + } >> > + >> > + size = get_unaligned_le32((void *)((uintptr_t)event + pos)); >> > + event_size += size; >> > + pos += sizeof(u32); /* tcg_pcr_event2 event_size*/ >> > + pos += size; >> > + >> > + /* make sure the calculated buffer is what we checked against */ >> > + if (pos != event_size) >> > + return EFI_COMPROMISED_DATA; >> > + >> > + if (pos > log_size) >> > + return EFI_COMPROMISED_DATA; >> > + >> > + *offset += pos; >> > + >> > + return EFI_SUCCESS; >> > +} >> > + >> > +efi_status_t tcg2_get_fw_eventlog(struct udevice *dev, void *log_buffer, >> > + size_t *log_sz) >> > +{ >> > + struct tpml_digest_values digest_list; >> > + efi_status_t ret; >> > + u32 pcr, pos; >> > + u64 base; >> > + u32 sz; >> > + >> > + ret = platform_get_eventlog(dev, &base, &sz); >> > + if (ret == EFI_SUCCESS) { >> > + void *buffer = (void *)base; >> > + >> > + if (sz > TPM2_EVENT_LOG_SIZE) >> > + return EFI_VOLUME_FULL; >> > + >> > + pos = 0; >> > + /* Parse the eventlog to check for its validity */ >> > + ret = parse_event_log_header(buffer, sz, &pos); >> > + if (ret || pos > sz) >> > + return EFI_COMPROMISED_DATA; >> > + >> > + ret = parse_specid_event(dev, buffer, sz, &pos, >> > &digest_list); >> > + if (ret || pos > sz) { >> > + log_err("Error parsing SPEC ID Event\n"); >> > + return EFI_COMPROMISED_DATA; >> > + } >> > + >> > + while (pos < sz) { >> > + ret = tcg2_parse_event(dev, buffer, sz, &pos, >> > + &digest_list, &pcr); >> > + if (ret) { >> > + log_err("Error parsing event\n"); >> > + return ret; >> > + } >> > + } >> > + >> > + memcpy(log_buffer, buffer, sz); >> > + *log_sz = sz; >> > + } >> > + >> > + return ret; >> > +} >> > + >> > /** >> > * create_specid_event() - Create the first event in the eventlog >> > * >> > @@ -1340,6 +1622,12 @@ static efi_status_t efi_init_event_log(void) >> > * last log entry >> > */ >> > memset(event_log.buffer, 0xff, TPM2_EVENT_LOG_SIZE); >> > + >> > + /* >> > + * The log header is defined to be in SHA1 event log entry format. >> > + * Setup event header >> > + */ >> > + event_header = (struct tcg_pcr_event *)event_log.buffer; >> > event_log.pos = 0; >> > event_log.last_event_size = 0; >> > event_log.get_event_called = false; >> > @@ -1347,22 +1635,28 @@ static efi_status_t efi_init_event_log(void) >> > event_log.truncated = false; >> > >> > /* >> > - * The log header is defined to be in SHA1 event log entry format. >> > - * Setup event header >> > + * Check if earlier firmware have passed any eventlog. Different >> > + * platforms can use different ways to do so >> > */ >> > - event_header = (struct tcg_pcr_event *)event_log.buffer; >> > - put_unaligned_le32(0, &event_header->pcr_index); >> > - put_unaligned_le32(EV_NO_ACTION, &event_header->event_type); >> > - memset(&event_header->digest, 0, sizeof(event_header->digest)); >> > - ret = create_specid_event(dev, (void >> > *)((uintptr_t)event_log.buffer + sizeof(*event_header)), >> > - &spec_event_size); >> > - if (ret != EFI_SUCCESS) >> > - goto free_pool; >> > - put_unaligned_le32(spec_event_size, &event_header->event_size); >> > - event_log.pos = spec_event_size + sizeof(*event_header); >> > - event_log.last_event_size = event_log.pos; >> > + ret = tcg2_get_fw_eventlog(dev, event_log.buffer, &event_log.pos); >> > + if (ret == EFI_NOT_FOUND) { >> > + put_unaligned_le32(0, &event_header->pcr_index); >> > + put_unaligned_le32(EV_NO_ACTION, >> > &event_header->event_type); >> > + memset(&event_header->digest, 0, >> > sizeof(event_header->digest)); >> > + ret = create_specid_event(dev, >> > + (void >> > *)((uintptr_t)event_log.buffer + >> > + sizeof(*event_header)), >> > + &spec_event_size); >> > + if (ret != EFI_SUCCESS) >> > + goto free_pool; >> > + put_unaligned_le32(spec_event_size, >> > &event_header->event_size); >> > + event_log.pos = spec_event_size + sizeof(*event_header); >> > + event_log.last_event_size = event_log.pos; >> > + } >> > + >> > + if (ret == EFI_SUCCESS) >> > + ret = create_final_event(); >> > >> > - ret = create_final_event(); >> > if (ret != EFI_SUCCESS) >> > goto free_pool; >> > >> > -- >> > 2.25.1 >> >
