Make tpmc able to send and receive raw datagrams.

This is immediately needed to debug a Parrot TPM problems, but
we've had similar situation in the past and probably will again
in the future.

BUG=chromium-os:37819
TEST=manually tested with a couple of different packets, and error inputs
BRANCH=none

Change-Id: Id7f66bdbdfe5887fa49cd62af4a9b807fa3d9a89
Reviewed-on: https://gerrit.chromium.org/gerrit/41166
Reviewed-by: Randall Spangler <rspangler@chromium.org>
Commit-Queue: Luigi Semenzato <semenzato@chromium.org>
Tested-by: Luigi Semenzato <semenzato@chromium.org>

3 files changed, 64 insertions, 2 deletions

diff --git a/firmware/include/tlcl.h b/firmware/include/tlcl.h
index 682bc86b..cd82fdca 100644
--- a/firmware/include/tlcl.h
+++ b/firmware/include/tlcl.h
@@ -33,6 +33,19 @@ void TlclLog(char* format, ...);
  */
 void TlclSetLogLevel(int level);
 
+/* Low-level operations */
+
+/* Performs a raw TPM request/response transaction.
+ */
+uint32_t TlclSendReceive(const uint8_t* request, uint8_t* response,
+                         int max_length);
+
+/* Returns the size of a TPM request or response packet.
+ */
+int TlclPacketSize(const uint8_t* packet);
+
+/* Commands */
+
 /* Sends a TPM_Startup(ST_CLEAR).  The TPM error code is returned (0
  * for success).
  */
diff --git a/firmware/lib/tpm_lite/tlcl.c b/firmware/lib/tpm_lite/tlcl.c
index 9a0801f5..332fd019 100644
--- a/firmware/lib/tpm_lite/tlcl.c
+++ b/firmware/lib/tpm_lite/tlcl.c
@@ -33,6 +33,11 @@ POSSIBLY_UNUSED static INLINE int TpmCommandSize(const uint8_t* buffer) {
   return (int) size;
 }
 
+/* Gets the size field of a TPM request or response. */
+int TlclPacketSize(const uint8_t* packet) {
+  return TpmCommandSize(packet);
+}
+
 /* Gets the code field of a TPM command. */
 static INLINE int TpmCommandCode(const uint8_t* buffer) {
   uint32_t code;
@@ -93,8 +98,8 @@ static uint32_t TlclSendReceiveNoRetry(const uint8_t* request,
 /* Sends a TPM command and gets a response.  Returns 0 if success or the TPM
  * error code if error. In the firmware, waits for the self test to complete
  * if needed. In the host, reports the first error without retries. */
-static uint32_t TlclSendReceive(const uint8_t* request, uint8_t* response,
-                                int max_length) {
+uint32_t TlclSendReceive(const uint8_t* request, uint8_t* response,
+                         int max_length) {
   uint32_t result = TlclSendReceiveNoRetry(request, response, max_length);
   /* When compiling for the firmware, hide command failures due to the self
    * test not having run or completed. */
diff --git a/utility/tpmc.c b/utility/tpmc.c
index c1a97f4b..898e2552 100644
--- a/utility/tpmc.c
+++ b/utility/tpmc.c
@@ -317,6 +317,48 @@ static uint32_t HandlerGetSTClearFlags(void) {
 }
 
 
+static uint32_t HandlerSendRaw(void) {
+  uint8_t request[4096];
+  uint8_t response[4096];
+  uint32_t result;
+  int size;
+  int i;
+  if (nargs == 2) {
+    fprintf(stderr, "usage: tpmc sendraw <hex byte 0> ... <hex byte N>\n");
+    exit(OTHER_ERROR);
+  }
+  for (i = 0; i < nargs - 2 && i < sizeof(request); i++) {
+    if (HexStringToUint8(args[2 + i], &request[i]) != 0) {
+      fprintf(stderr, "bad byte value \"%s\"\n", args[2 + i]);
+      exit(OTHER_ERROR);
+    }
+  }
+  size = TlclPacketSize(request);
+  if (size != i) {
+    fprintf(stderr, "bad request: size field is %d, but packet has %d bytes\n",
+            size, i);
+    exit(OTHER_ERROR);
+  }
+  bzero(response, sizeof(response));
+  result = TlclSendReceive(request, response, sizeof(response));
+  if (result != 0) {
+    fprintf(stderr, "request failed with code %d\n", result);
+  }
+  size = TlclPacketSize(response);
+  if (size < 10 || size > sizeof(response)) {
+    fprintf(stderr, "unexpected response size %d\n", size);
+    exit(OTHER_ERROR);
+  }
+  for (i = 0; i < size; i++) {
+    printf("0x%02x ", response[i]);
+    if (i == size - 1 || (i + 1) % 8 == 0) {
+      printf("\n");
+    }
+  }
+  return result;
+}
+
+
 /* Table of TPM commands.
  */
 command_record command_table[] = {
@@ -363,6 +405,8 @@ command_record command_table[] = {
     HandlerGetSTClearFlags },
   { "resume", "res", "execute TPM_Startup(ST_STATE)", TlclResume },
   { "savestate", "save", "execute TPM_SaveState", TlclSaveState },
+  { "sendraw", "raw", "send a raw request and print raw response",
+    HandlerSendRaw },
 };
 
 static int n_commands = sizeof(command_table) / sizeof(command_table[0]);