tpm: Implement tpm20_extend

Implement the tpm20_extend function. We use it with only SHA1.

Signed-off-by: Stefan Berger <stefanb@linux.vnet.ibm.com>

1 files changed, 32 insertions, 2 deletions

diff --git a/src/tcgbios.c b/src/tcgbios.c
index a99d58d6..435e2ebc 100644
--- a/src/tcgbios.c
+++ b/src/tcgbios.c
@@ -361,6 +361,37 @@ tpm12_extend(u32 pcrindex, const u8 *digest)
     return 0;
 }
 
+static int tpm20_extend(u32 pcrindex, const u8 *digest)
+{
+    struct tpm2_req_extend tre = {
+        .hdr.tag     = cpu_to_be16(TPM2_ST_SESSIONS),
+        .hdr.totlen  = cpu_to_be32(sizeof(tre)),
+        .hdr.ordinal = cpu_to_be32(TPM2_CC_PCR_Extend),
+        .pcrindex    = cpu_to_be32(pcrindex),
+        .authblocksize = cpu_to_be32(sizeof(tre.authblock)),
+        .authblock = {
+            .handle = cpu_to_be32(TPM2_RS_PW),
+            .noncesize = cpu_to_be16(0),
+            .contsession = TPM2_YES,
+            .pwdsize = cpu_to_be16(0),
+        },
+        .digest = {
+            .count = cpu_to_be32(1),
+            .hashalg = cpu_to_be16(TPM2_ALG_SHA1),
+        },
+    };
+    memcpy(tre.digest.sha1, digest, sizeof(tre.digest.sha1));
+
+    struct tpm_rsp_header rsp;
+    u32 resp_length = sizeof(rsp);
+    int ret = tpmhw_transmit(0, &tre.hdr, &rsp, &resp_length,
+                             TPM_DURATION_TYPE_SHORT);
+    if (ret || resp_length != sizeof(rsp) || rsp.errcode)
+        return -1;
+
+    return 0;
+}
+
 static int
 tpm_extend(u32 pcrindex, const u8 *digest)
 {
@@ -371,8 +402,7 @@ tpm_extend(u32 pcrindex, const u8 *digest)
     case TPM_VERSION_1_2:
         return tpm12_extend(pcrindex, digest);
     case TPM_VERSION_2:
-        // FIXME: missing code
-        return -1;
+        return tpm20_extend(pcrindex, digest);
     }
     return -1;
 }