Hi Heinrich, On Fri, 26 Nov 2021 at 13:01, Heinrich Schuchardt <xypron.g...@gmx.de> wrote:
> On 11/26/21 06:00, Ruchika Gupta 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. > > > > Signed-off-by: Ruchika Gupta <ruchika.gu...@linaro.org> > > Tested-by: Ilias Apalodimas <ilias.apalodi...@linaro.org> > > Reviewed-by: Ilias Apalodimas <ilias.apalodi...@linaro.org> > > --- > > v6: No change > > > > v5: > > Shift the efi_init_event_log() to a different location in the file. > > This help fixes compilation issue introduced by calling > efi_append_scrtm_version() > > from it. > > > > v4: > > Add SCRTM version to log only if previous firmware doesn't pass the > eventlog > > > > v3: > > Return as soon as you detect error > > > > v2: > > Moved firmware eventlog code parsing to tcg2_get_fw_eventlog() > > > > lib/efi_loader/efi_tcg2.c | 438 ++++++++++++++++++++++++++++++++------ > > 1 file changed, 369 insertions(+), 69 deletions(-) > > > > diff --git a/lib/efi_loader/efi_tcg2.c b/lib/efi_loader/efi_tcg2.c > > index 8c1f22e337..a789c44660 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) > > This function must be declared in a header to be overridden. > > > +{ > > + 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 +1220,250 @@ 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) > > This function should be declared in a header or be static. > > Should buffer have type struct tcg_pcr_event *? > Since buffer points to the complete eventlog, it would be probably better to keep it as it is i.e void *. I will correct the description of this parameter in the function description to avoid confusion. > > +{ > > + 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) > > if (event_header->digest[i]) > > > + return EFI_COMPROMISED_DATA; > > + } > > + > > + *pos += sizeof(*event_header); > > Do you re > Probably you are asking about parameter pos here. pos points to the offset in the buffer where the next event starts (after the 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 > > Duplicate line > > > + * @digest_list: list of digests in the event > > Misplaced line > > > + */ > > +efi_status_t parse_specid_event(struct udevice *dev, void *buffer, u32 > log_size, > > + u32 *pos, > > + struct tpml_digest_values *digest_list) > > +{ > > This function should be declared in a header or be static. > > > + 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 > > %s/algs/algorithms/ > > > + * subsequent entries in event should be in same order > > "We need to worry" sounds like a FIXME. Is there anything to fix or do > you mean: > > We have to take care that the sequence of algorithms that we record in > digest_list matches the sequence in the event log. > > > + */ > > + 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 */ > > The TCG specification > > > + 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; > > +} > > + > > Missing function description > > > +efi_status_t tcg2_parse_event(struct udevice *dev, void *buffer, u32 > log_size, > > + u32 *offset, struct tpml_digest_values > *digest_list, > > + u32 *pcr) > > Exported functions should be declared in a header. > Or should this function be static? > > > +{ > > + 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; > > +} > > + > > Missing function description. > > > +efi_status_t tcg2_get_fw_eventlog(struct udevice *dev, void *log_buffer, > > + size_t *log_sz) > > This function should be declared in a header or should be static. > > > +{ > > + struct tpml_digest_values digest_list; > > + void *buffer; > > + efi_status_t ret; > > + u32 pcr, pos; > > + u64 base; > > + u32 sz; > > + > > + ret = platform_get_eventlog(dev, &base, &sz); > > + if (ret != EFI_SUCCESS) > > + return ret; > > + > > + if (sz > TPM2_EVENT_LOG_SIZE) > > + return EFI_VOLUME_FULL; > > + > > + buffer = (void *)base; > > Superfluous conversion. > Sorry, I didn't get this comment. If you meant removing the typecast, base is u64 so when assigning it to a void pointer, cast would be needed. On removing the case, I get this warning buffer = base; lib/efi_loader/efi_tcg2.c:1518:9: warning: assignment to ‘void *’ from ‘u64’ {aka ‘long long unsigned int’} makes pointer from integer without a cast [-Wint-conversion] 1518 | buffer = base; [...] Regards, Ruchika