tpm: add TPM2_PCR_Extend command support

[oweals/u-boot.git] / lib / tpm-v2.c

diff --git a/lib/tpm-v2.c b/lib/tpm-v2.c
index 34a93ab06717abcfdcfdc03083a9ff9df260336d..476b4ee0d083bd4f136e6a9c840a7ab0826ba343 100644 (file)
--- a/lib/tpm-v2.c
+++ b/lib/tpm-v2.c
@@ -77,3 +77,41 @@ u32 tpm2_clear(u32 handle, const char *pw, const ssize_t pw_sz)
 
        return tpm_sendrecv_command(command_v2, NULL, NULL);
 }
+
+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);
+}