This commit implements grub_tcg2_cap_pcr() for EFI by using the UEFI
TCG2 protocol, HashLogExtendEvent, to extend the specified PCR with a
SEPARATOR event and ensure the event will be recorded properly in the
TPM event log.
Signed-off-by: Gary Lin <g...@suse.com>
---
grub-core/lib/efi/tcg2.c | 41 ++++++++++++++++++++++++++++++++++++++++
1 file changed, 41 insertions(+)
diff --git a/grub-core/lib/efi/tcg2.c b/grub-core/lib/efi/tcg2.c
index 841bf50bb..81f5dea24 100644
--- a/grub-core/lib/efi/tcg2.c
+++ b/grub-core/lib/efi/tcg2.c
@@ -22,6 +22,7 @@
#include <grub/efi/tpm.h>
#include <grub/mm.h>
+#include <tss2_types.h>
#include <tcg2.h>
static grub_err_t
@@ -141,3 +142,43 @@ grub_tcg2_submit_command (grub_size_t input_size,
return GRUB_ERR_NONE;
}
+
+grub_err_t
+grub_tcg2_cap_pcr (grub_uint8_t pcr)
+{
+ grub_err_t err;
+ grub_efi_status_t status;
+ grub_efi_tpm2_protocol_t *protocol;
+ EFI_TCG2_EVENT *event;
+ grub_uint8_t separator[4] = {0};
+
+ if (pcr >= TPM_MAX_PCRS)
+ return GRUB_ERR_BAD_ARGUMENT;
+
+ err = tcg2_get_protocol (&protocol);
+ if (err != GRUB_ERR_NONE)
+ return err;
+
+ event = grub_zalloc (sizeof (EFI_TCG2_EVENT) + sizeof (separator));
+ if (!event)
+ return grub_error (GRUB_ERR_OUT_OF_MEMORY,
+ N_("cannot allocate TPM event buffer"));
+
+ event->Header.HeaderSize = sizeof (EFI_TCG2_EVENT_HEADER);
+ event->Header.HeaderVersion = 1;
+ event->Header.PCRIndex = pcr;
+ event->Header.EventType = EV_SEPARATOR;
+ event->Size = sizeof (*event) - sizeof (event->Event) + sizeof (separator);
+ grub_memcpy (event->Event, separator, sizeof (separator));
+
+
+ status = protocol->hash_log_extend_event (protocol, 0,
+ (grub_addr_t) separator,
+ sizeof (separator), event);
+ grub_free (event);
+
+ if (status != GRUB_EFI_SUCCESS)
+ return grub_error (GRUB_ERR_BAD_DEVICE, N_("cannot cap PCR %u"), pcr);
+
+ return GRUB_ERR_NONE;
+}
--
2.43.0
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