From 7bbb41a1fd9cf4e11d036311a91f9fa5260497ec Mon Sep 17 00:00:00 2001
From: Stefan Berger <stefanb@linux.vnet.ibm.com>
Date: Sat, 10 Mar 2018 19:13:01 -0500
Subject: [PATCH] Modify TPM_NVRAM_LoadData() to try to get cached state blob

Modify TPM_NVRAM_LoadData() to try to get the cached state blob before trying
to read the state blob from the file. We clear the state blob as part of
passing it to the TPM.

A side effect is now that if TPMLIB_ValidateState is called on a blob that
this call would not remove the cached blob. So we have to save a copy before
reading (and parsing) the state blob so we still have it when TPM_MainInit()
is called.

Signed-off-by: Stefan Berger <stefanb@linux.vnet.ibm.com>
---
 src/tpm12/tpm_nvfile.c    | 13 ++++++++++++-
 src/tpm_tpm12_interface.c |  9 ++++++++-
 2 files changed, 20 insertions(+), 2 deletions(-)

diff --git a/src/tpm12/tpm_nvfile.c b/src/tpm12/tpm_nvfile.c
index e0fe711d..c8e7bcf5 100644
--- a/src/tpm12/tpm_nvfile.c
+++ b/src/tpm12/tpm_nvfile.c
@@ -64,6 +64,7 @@
 
 #ifdef TPM_LIBTPMS_CALLBACKS
 #include "tpm_library_intern.h"
+#include "tpm_library.h"
 #endif
 
 
@@ -162,7 +163,17 @@ TPM_RESULT TPM_NVRAM_LoadData(unsigned char **data,     /* freed by caller */
     char        filename[FILENAME_MAX]; /* rooted file name from name */
 
 #ifdef TPM_LIBTPMS_CALLBACKS
-    struct libtpms_callbacks *cbs = TPMLIB_GetCallbacks();
+    struct libtpms_callbacks *cbs;
+    bool is_empty_buffer;
+
+    /* try to get state blob set with TPMLIB_SetState() */
+    GetCachedState(TPMLIB_NameToStateType(name), data, length, &is_empty_buffer);
+    if (is_empty_buffer)
+        return TPM_RETRY;
+    if (*data)
+        return TPM_SUCCESS;
+
+    cbs = TPMLIB_GetCallbacks();
 
     /* call user-provided function if available, otherwise execute
        default behavior */
diff --git a/src/tpm_tpm12_interface.c b/src/tpm_tpm12_interface.c
index 55ba3741..b651e6e6 100644
--- a/src/tpm_tpm12_interface.c
+++ b/src/tpm_tpm12_interface.c
@@ -273,6 +273,7 @@ TPM_RESULT TPM12_ValidateState(enum TPMLIB_StateType st,
         TPMLIB_STATE_SAVE_STATE,
         0,
     };
+    enum TPMLIB_StateType c_st;
     unsigned i;
 
 #ifdef TPM_LIBTPMS_CALLBACKS
@@ -289,7 +290,13 @@ TPM_RESULT TPM12_ValidateState(enum TPMLIB_StateType st,
     tpm_state.tpm_number = 0;
 
     for (i = 0; sts[i] && ret == TPM_SUCCESS; i++) {
-        switch (st & sts[i]) {
+        c_st = st & sts[i];
+
+        /* 'cached' state is known to 'work', so skip it */
+        if (!c_st || !HasCachedState(c_st))
+            continue;
+
+        switch (c_st) {
         case TPMLIB_STATE_PERMANENT:
             ret = TPM_PermanentAll_NVLoad(&tpm_state);
             break;