Fix load_kernel_test, add check to LoadKernel to detect bad args.

firmware/lib/vboot_kernel.c

 /* Copyright (c) 2010 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 94 matching lines @@
   }
 
   /* Success */
   return 0;
 }
 
 /* disable MSVC warning on const logical expression (as in } while(0);) */
 __pragma(warning(disable: 4127))
 
 int LoadKernel(LoadKernelParams* params) {
-
-  VbPublicKey* kernel_subkey = (VbPublicKey*)params->header_sign_key_blob;
-
+  VbPublicKey* kernel_subkey;
   GptData gpt;
   uint64_t part_start, part_size;
-  uint64_t blba = params->bytes_per_lba;
-  uint64_t kbuf_sectors = KBUF_SIZE / blba;
+  uint64_t blba;
+  uint64_t kbuf_sectors;
   uint8_t* kbuf = NULL;
   int found_partitions = 0;
   int good_partition = -1;
   uint16_t tpm_key_version = 0;
   uint16_t tpm_kernel_version = 0;
   uint64_t lowest_key_version = 0xFFFF;
   uint64_t lowest_kernel_version = 0xFFFF;
-  int is_dev = (BOOT_FLAG_DEVELOPER & params->boot_flags ? 1 : 0);
-  int is_rec = (BOOT_FLAG_RECOVERY & params->boot_flags ? 1 : 0);
-  int is_normal = (!is_dev && !is_rec);
+  int is_dev;
+  int is_rec;
+  int is_normal;
   uint32_t status;
 
+  /* Sanity Checks */
+  if (!params ||
+      !params->header_sign_key_blob ||
+      !params->bytes_per_lba ||
+      !params->ending_lba ||
+      !params->kernel_buffer ||
+      !params->kernel_buffer_size) {
+    VBDEBUG(("LoadKernel() called with invalid params\n"));
+    return LOAD_KERNEL_INVALID;
+  }
+
+  /* Initialization */
+  kernel_subkey = (VbPublicKey*)params->header_sign_key_blob;
+  blba = params->bytes_per_lba;
+  kbuf_sectors = KBUF_SIZE / blba;
+  is_dev = (BOOT_FLAG_DEVELOPER & params->boot_flags ? 1 : 0);
+  is_rec = (BOOT_FLAG_RECOVERY & params->boot_flags ? 1 : 0);
+  is_normal = (!is_dev && !is_rec);
+
   /* Clear output params in case we fail */
   params->partition_number = 0;
   params->bootloader_address = 0;
   params->bootloader_size = 0;
 
   if (!is_dev) {
     /* TODO: should use the TPM all the time; for now, only use when
      * not in developer mode. */
     /* Let the TPM know if we're in recovery mode */
     if (is_rec) {
@@ skipping 262 matching lines @@
     /* Success! */
     return LOAD_KERNEL_SUCCESS;
   }
 
   // Handle error cases
   if (found_partitions)
     return LOAD_KERNEL_INVALID;
   else
     return LOAD_KERNEL_NOT_FOUND;
 }