tpm_lite: Implement ReadPubek command.

Add a TlclReadPubek library function to read the public endorsement
key.

BRANCH=None
BUG=chromium:788719
TEST=New unit tests.

Change-Id: I5f23b76b88198d656f4ba5782d2b4f25aaa082b1
Reviewed-on: https://chromium-review.googlesource.com/790413
Reviewed-by: Andrey Pronin <apronin@chromium.org>
Tested-by: Mattias Nissler <mnissler@chromium.org>
Trybot-Ready: ChromeOS CL Exonerator Bot <chromiumos-cl-exonerator@appspot.gserviceaccount.com>
Trybot-Ready: Mattias Nissler <mnissler@chromium.org>

4 files changed, 43 insertions, 0 deletions

diff --git a/firmware/include/tlcl.h b/firmware/include/tlcl.h
index b38c3d69..685925f4 100644
--- a/firmware/include/tlcl.h
+++ b/firmware/include/tlcl.h
@@ -230,6 +230,19 @@ uint32_t TlclGetVersion(uint32_t* vendor, uint64_t* firmware_version,
  */
 uint32_t TlclIFXFieldUpgradeInfo(TPM_IFX_FIELDUPGRADEINFO *info);
 
+#ifdef CHROMEOS_ENVIRONMENT
+#ifndef TPM2_MODE
+
+/**
+ * Read the public half of the EK.
+ */
+uint32_t TlclReadPubek(uint32_t* public_exponent,
+                       uint8_t* modulus,
+                       uint32_t* modulus_size);
+
+#endif  /* TPM2_MODE */
+#endif  /* CHROMEOS_ENVIRONMENT */
+
 #ifdef __cplusplus
 }
 #endif
diff --git a/firmware/include/tpm1_tss_constants.h b/firmware/include/tpm1_tss_constants.h
index 97d7358f..f915fb53 100644
--- a/firmware/include/tpm1_tss_constants.h
+++ b/firmware/include/tpm1_tss_constants.h
@@ -55,6 +55,12 @@ typedef uint32_t TPM_CAPABILITY_AREA;
 #define TPM_CAP_NV_INDEX        ((uint32_t) 0x00000011)
 #define TPM_CAP_GET_VERSION_VAL ((uint32_t) 0x0000001a)
 
+#define TPM_ALG_RSA ((uint16_t)0x0001)
+
+#define TPM_ES_RSAESOAEP_SHA1_MGF1 ((uint16_t)0x0003)
+
+#define TPM_SS_NONE ((uint16_t)0x0001)
+
 #define TPM_ST_CLEAR       ((uint16_t) 0x0001)
 #define TPM_ST_STATE       ((uint16_t) 0x0002)
 #define TPM_ST_DEACTIVATED ((uint16_t) 0x0003)
@@ -77,6 +83,10 @@ typedef uint32_t TPM_CAPABILITY_AREA;
 #define TPM_SHA1_160_HASH_LEN    0x14
 #define TPM_SHA1BASED_NONCE_LEN  TPM_SHA1_160_HASH_LEN
 
+#define TPM_AUTH_DATA_LEN    0x14
+
+#define TPM_RSA_2048_LEN    0x100
+
 typedef struct tdTPM_DIGEST
 {
     uint8_t  digest[TPM_SHA1_160_HASH_LEN];
diff --git a/firmware/include/tss_constants.h b/firmware/include/tss_constants.h
index 1fe92b92..d579933e 100644
--- a/firmware/include/tss_constants.h
+++ b/firmware/include/tss_constants.h
@@ -23,6 +23,10 @@
 #define TPM_E_READ_FAILURE           ((uint32_t) 0x0000500a)  /* vboot local */
 #define TPM_E_STRUCT_SIZE            ((uint32_t) 0x0000500b)  /* vboot local */
 #define TPM_E_STRUCT_VERSION         ((uint32_t) 0x0000500c)  /* vboot local */
+#define TPM_E_INTERNAL_ERROR         ((uint32_t) 0x0000500d)  /* vboot local */
+#define TPM_E_INVALID_RESPONSE       ((uint32_t) 0x0000500e)  /* vboot local */
+#define TPM_E_BUFFER_SIZE            ((uint32_t) 0x0000500f)  /* vboot local */
+
 
 /*
  * AP firmware relies on Tlcl returning these exact TPM1.2 error codes
@@ -31,6 +35,7 @@
  * either 0x100 or 0x80 bit set, so there is no confusion with actual error
  * codes returned from a TPM2.0 chip.
  */
+#define TPM_E_AUTHFAIL              ((uint32_t) 0x00000001)
 #define TPM_E_BADINDEX              ((uint32_t) 0x00000002)
 #define TPM_E_BAD_ORDINAL           ((uint32_t) 0x0000000a)
 #define TPM_E_OWNER_SET             ((uint32_t) 0x00000014)
diff --git a/firmware/include/vboot_api.h b/firmware/include/vboot_api.h
index d05fef86..04836ff8 100644
--- a/firmware/include/vboot_api.h
+++ b/firmware/include/vboot_api.h
@@ -419,6 +419,21 @@ VbError_t VbExTpmOpen(void);
 VbError_t VbExTpmSendReceive(const uint8_t *request, uint32_t request_length,
                              uint8_t *response, uint32_t *response_length);
 
+#ifdef CHROMEOS_ENVIRONMENT
+
+/**
+ * Obtain cryptographically secure random bytes. This function is used to
+ * generate random nonces for TPM auth sessions for example. As an implication,
+ * the generated random bytes should not be predictable for a TPM communication
+ * interception attack. This implies a local source of randomness should be
+ * used, i.e. this should not be wired to the TPM RNG directly. Otherwise, an
+ * attacker with communication interception abilities could launch replay
+ * attacks by reusing previous nonces.
+ */
+VbError_t VbExTpmGetRandom(uint8_t *buf, uint32_t length);
+
+#endif  /* CHROMEOS_ENVIRONMENT */
+
 /*****************************************************************************/
 /* Non-volatile storage */