vTPM/TPM2: TPM 2.0 PCRs read

Signed-off-by: Quan Xu <quan.xu@intel.com>
Acked-by: Daniel De Graaf <dgdegra@tycho.nsa.gov>

stubdom/vtpmmgr/init.c

@@ -51,6 +51,7 @@
 #include "vtpm_disk.h"
 #include "tpm.h"
 #include "marshal.h"
+#include "tpm2_marshal.h"
 #include "tpm2.h"
 
 struct Opts {
@@ -754,3 +755,36 @@ abort_egress:
 egress:
     return status;
 }
+
+TPM_RC tpm2_pcr_read(int index, uint8_t *buf)
+{
+    TPM_RESULT status = TPM_SUCCESS;
+    TPML_PCR_SELECTION pcrSelectionIn = {
+        .count = 1,};
+
+    TPMS_PCR_SELECTION tpms_pcr_selection = {
+        .hash = TPM2_ALG_SHA1,
+        .sizeofSelect = PCR_SELECT_MAX,};
+
+    UINT32 pcrUpdateCounter;
+    TPML_PCR_SELECTION pcrSelectionOut;
+    TPML_DIGEST pcrValues;
+    TPM2B_DIGEST tpm2b_digest;
+
+    tpms_pcr_selection.pcrSelect[PCR_SELECT_NUM(index)] = PCR_SELECT_VALUE(index);
+    memcpy(&pcrSelectionIn.pcrSelections[0], &tpms_pcr_selection,
+           sizeof(TPMS_PCR_SELECTION));
+
+    TPMTRYRETURN(TPM2_PCR_Read(pcrSelectionIn, &pcrUpdateCounter,
+                               &pcrSelectionOut, &pcrValues));
+
+    if (pcrValues.count < 1)
+        goto egress;
+
+    unpack_TPM2B_DIGEST((uint8_t *) &pcrValues, &tpm2b_digest);
+    memcpy(buf, tpm2b_digest.buffer, SHA1_DIGEST_SIZE);
+
+abort_egress:
+egress:
+    return status;
+}

stubdom/vtpmmgr/tpm2_types.h

@@ -432,6 +432,8 @@ typedef struct {
 #define    IMPLEMENTATION_PCR   24
 #define    PLATFORM_PCR         24
 #define    PCR_SELECT_MAX       ((IMPLEMENTATION_PCR+7)/8)
+#define    PCR_SELECT_NUM(x)    (uint8_t)(x/8)
+#define    PCR_SELECT_VALUE(x)  (uint8_t)(0x1)<<(x%8)
 
 //Table 79 -- TPMS_PCR_SELECT Structure <I/O>
 typedef struct {

stubdom/vtpmmgr/vtpmmgr.h

@@ -107,6 +107,7 @@ inline TPM_RESULT vtpmmgr_rand(unsigned char* bytes, size_t num_bytes) {
 
 /* TPM 2.0 */
 TPM_RC tpm2_take_ownership(void);
+TPM_RC tpm2_pcr_read(int index, uint8_t *buf);
 TPM_RESULT vtpmmgr2_create(void);
 TPM_RESULT vtpmmgr2_init(int argc, char** argv);
 int parse_cmdline_hw(int argc, char** argv);