diff options
Diffstat (limited to 'include/linux/tpm_eventlog.h')
| -rw-r--r-- | include/linux/tpm_eventlog.h | 23 |
1 files changed, 21 insertions, 2 deletions
diff --git a/include/linux/tpm_eventlog.h b/include/linux/tpm_eventlog.h index 4f8c90c93c29..739ba9a03ec1 100644 --- a/include/linux/tpm_eventlog.h +++ b/include/linux/tpm_eventlog.h @@ -81,6 +81,8 @@ struct tcg_efi_specid_event_algs { u16 digest_size; } __packed; +#define TCG_SPECID_SIG "Spec ID Event03" + struct tcg_efi_specid_event_head { u8 signature[16]; u32 platform_class; @@ -171,6 +173,7 @@ static inline int __calc_tpm2_event_size(struct tcg_pcr_event2_head *event, int i; int j; u32 count, event_type; + const u8 zero_digest[sizeof(event_header->digest)] = {0}; marker = event; marker_start = marker; @@ -198,10 +201,26 @@ static inline int __calc_tpm2_event_size(struct tcg_pcr_event2_head *event, count = READ_ONCE(event->count); event_type = READ_ONCE(event->event_type); + /* Verify that it's the log header */ + if (event_header->pcr_idx != 0 || + event_header->event_type != NO_ACTION || + memcmp(event_header->digest, zero_digest, sizeof(zero_digest))) { + size = 0; + goto out; + } + efispecid = (struct tcg_efi_specid_event_head *)event_header->event; - /* Check if event is malformed. */ - if (count > efispecid->num_algs) { + /* + * Perform validation of the event in order to identify malformed + * events. This function may be asked to parse arbitrary byte sequences + * immediately following a valid event log. The caller expects this + * function to recognize that the byte sequence is not a valid event + * and to return an event size of 0. + */ + if (memcmp(efispecid->signature, TCG_SPECID_SIG, + sizeof(TCG_SPECID_SIG)) || + !efispecid->num_algs || count != efispecid->num_algs) { size = 0; goto out; } |