tpm: Factor out tpm_extend

In preparation for TPM 2 code support, factor out the TPM 1.2 specific
code from tpm_log_extend_event and put it into tpm_extend().

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

1 files changed, 14 insertions, 4 deletions

diff --git a/src/tcgbios.c b/src/tcgbios.c
index 0559083f..799a8bf3 100644
--- a/src/tcgbios.c
+++ b/src/tcgbios.c
@@ -287,18 +287,18 @@ determine_timeouts(void)
 }
 
 static int
-tpm_log_extend_event(struct pcpes *pcpes, const void *event)
+tpm_extend(u32 pcrindex, const u8 *digest)
 {
-    if (pcpes->pcrindex >= 24)
+    if (pcrindex >= 24)
         return -1;
 
     struct tpm_req_extend tre = {
         .hdr.tag     = cpu_to_be16(TPM_TAG_RQU_CMD),
         .hdr.totlen  = cpu_to_be32(sizeof(tre)),
         .hdr.ordinal = cpu_to_be32(TPM_ORD_Extend),
-        .pcrindex    = cpu_to_be32(pcpes->pcrindex),
+        .pcrindex    = cpu_to_be32(pcrindex),
     };
-    memcpy(tre.digest, pcpes->digest, sizeof(tre.digest));
+    memcpy(tre.digest, digest, sizeof(tre.digest));
 
     struct tpm_rsp_extend rsp;
     u32 resp_length = sizeof(rsp);
@@ -307,6 +307,16 @@ tpm_log_extend_event(struct pcpes *pcpes, const void *event)
     if (ret || resp_length != sizeof(rsp) || rsp.hdr.errcode)
         return -1;
 
+    return 0;
+}
+
+static int
+tpm_log_extend_event(struct pcpes *pcpes, const void *event)
+{
+    int ret = tpm_extend(pcpes->pcrindex, pcpes->digest);
+    if (ret)
+        return -1;
+
     return tpm_log_event(pcpes, event);
 }