+
+u32 tpm2_pcr_extend(u32 index, const uint8_t *digest)
+{
+ u8 command_v2[COMMAND_BUFFER_SIZE] = {
+ tpm_u16(TPM2_ST_SESSIONS), /* TAG */
+ tpm_u32(33 + TPM2_DIGEST_LEN), /* Length */
+ tpm_u32(TPM2_CC_PCR_EXTEND), /* Command code */
+
+ /* HANDLE */
+ tpm_u32(index), /* Handle (PCR Index) */
+
+ /* AUTH_SESSION */
+ tpm_u32(9), /* Authorization size */
+ tpm_u32(TPM2_RS_PW), /* Session handle */
+ tpm_u16(0), /* Size of <nonce> */
+ /* <nonce> (if any) */
+ 0, /* Attributes: Cont/Excl/Rst */
+ tpm_u16(0), /* Size of <hmac/password> */
+ /* <hmac/password> (if any) */
+ tpm_u32(1), /* Count (number of hashes) */
+ tpm_u16(TPM2_ALG_SHA256), /* Algorithm of the hash */
+ /* STRING(digest) Digest */
+ };
+ unsigned int offset = 33;
+ int ret;
+
+ /*
+ * Fill the command structure starting from the first buffer:
+ * - the digest
+ */
+ ret = pack_byte_string(command_v2, sizeof(command_v2), "s",
+ offset, digest, TPM2_DIGEST_LEN);
+ offset += TPM2_DIGEST_LEN;
+ if (ret)
+ return TPM_LIB_ERROR;
+
+ return tpm_sendrecv_command(command_v2, NULL, NULL);
+}