Do not advance kernel version in TPM if we are in firmware B trying a new firmware

firmware/lib/vboot_kernel.c

 /* Copyright (c) 2011 The Chromium OS Authors. All rights reserved.
  * Use of this source code is governed by a BSD-style license that can be
  * found in the LICENSE file.
  *
  * Functions for loading a kernel from disk.
  * (Firmware portion)
  */
 
 #include "vboot_kernel.h"
 
@@ skipping 579 matching lines @@
   /* Write and free GPT data */
   WriteAndFreeGptData(&gpt);
 
   /* Handle finding a good partition */
   if (good_partition >= 0) {
     VBDEBUG(("Good_partition >= 0\n"));
     if (shcall)
       shcall->check_result = VBSD_LKC_CHECK_GOOD_PARTITION;
 
     /* See if we need to update the TPM */
-    if (kBootRecovery != boot_mode && good_partition_key_block_valid) {
-      /* We only update the TPM in normal and developer boot modes.  In
-       * developer mode, we only advanced lowest_version for kernels with valid
-       * key blocks, and didn't count self-signed key blocks.  In recovery
-       * mode, the TPM stays PP-unlocked, so anything we write gets blown away
-       * by the firmware when we go back to normal mode. */
-      VBDEBUG(("Boot_flags = not recovery\n"));
+    if ((kBootRecovery != boot_mode) &&

[Sumit, 2011/04/17 17:11:12]

Do we need to set TPM in developer firmware? I agree about normal mode and
developer mode with normal firmware but not sure about developer firmware.

+        good_partition_key_block_valid &&
+        !((1 == shared->firmware_index) && (shared->flags & VBSD_FWB_TRIED))) {
+      /* We only update the TPM in normal and developer boot modes.
+       * In developer mode, we only advanced lowest_version for
+       * kernels with valid key blocks, and didn't count self-signed
+       * key blocks. Recovery kernels aren't numbered, so we don't
+       * update the TPM in recovery mode.  We don't advance the TPM if
+       * we're trying a new firmware B, because that firmware may have a
+       * key change and roll forward the TPM too soon. */
+      VBDEBUG(("Checking if TPM kernel version needs advancing\n"));
 
       if ((lowest_version > tpm_version) &&
           (lowest_version != LOWEST_TPM_VERSION)) {
         status = RollbackKernelWrite((uint32_t)lowest_version);
         if (0 != status) {
           VBDEBUG(("Error writing kernel versions to TPM.\n"));
           if (status == TPM_E_MUST_REBOOT)
             retval = LOAD_KERNEL_REBOOT;
           else
             recovery = VBNV_RECOVERY_RW_TPM_ERROR;
@@ skipping 49 matching lines @@
 
     /* Save timer values */
     shared->timer_load_kernel_enter = timer_enter;
     shared->timer_load_kernel_exit = VbGetTimer();
     /* Store how much shared data we used, if any */
     params->shared_data_size = shared->data_used;
   }
 
   return retval;
 }