Merge tag 'tpmdd-next-v5.9' of git://git.infradead.org/users/jjs/linux-tpmdd

Pull tpm updates from Jarkko Sakkinen:
 "An issue was fixed with the TPM space buffer size. The buffer is used
  to store in-TPM objects while swapped out of the TPM for a /dev/tpmrm0
  session. The code incorrectly used PAGE_SIZE, which obviously can
  vary. With these changes the buffer has a fixed size of 16 kB.

  In addition, this contains support for acquiring TPM even log from
  TPM2 ACPI table. This method is used by QEMU in particular"

* tag 'tpmdd-next-v5.9' of git://git.infradead.org/users/jjs/linux-tpmdd:
  tpm: Add support for event log pointer found in TPM2 ACPI table
  acpi: Extend TPM2 ACPI table with missing log fields
  tpm: Unify the mismatching TPM space buffer sizes
  tpm: Require that all digests are present in TCG_PCR_EVENT2 structures

2 files changed, 10 insertions, 2 deletions

diff --git a/include/linux/tpm.h b/include/linux/tpm.h
index 03e9b184411b..8f4ff39f51e7 100644
--- a/include/linux/tpm.h
+++ b/include/linux/tpm.h
@@ -96,6 +96,7 @@ struct tpm_space {
 	u8 *context_buf;
 	u32 session_tbl[3];
 	u8 *session_buf;
+	u32 buf_size;
 };
 
 struct tpm_bios_log {
diff --git a/include/linux/tpm_eventlog.h b/include/linux/tpm_eventlog.h
index 64356b199e94..739ba9a03ec1 100644
--- a/include/linux/tpm_eventlog.h
+++ b/include/linux/tpm_eventlog.h
@@ -211,9 +211,16 @@ static inline int __calc_tpm2_event_size(struct tcg_pcr_event2_head *event,
 
 	efispecid = (struct tcg_efi_specid_event_head *)event_header->event;
 
-	/* Check if event is malformed. */
+	/*
+	 * 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)) || count > efispecid->num_algs) {
+		   sizeof(TCG_SPECID_SIG)) ||
+	    !efispecid->num_algs || count != efispecid->num_algs) {
 		size = 0;
 		goto out;
 	}