VBoot Reference: Add kernel rollback prevention and choosing logic.

src/platform/vboot_reference/include/kernel_image.h

 /* 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.
  *
  * Data structure and API definitions for a verified boot kernel image.
  */
 
 #ifndef VBOOT_REFERENCE_KERNEL_IMAGE_H_
 #define VBOOT_REFERENCE_KERNEL_IMAGE_H_
 
 #include <inttypes.h>
 
 #include "rsa.h"
 #include "sha.h"
 
 #define KERNEL_MAGIC "CHROMEOS"
 #define KERNEL_MAGIC_SIZE 8
 #define KERNEL_CMD_LINE_SIZE 4096
 
+#define DEV_MODE_ENABLED 1
+#define DEV_MODE_DISABLED 0
+
 /* Kernel config file options according to the Chrome OS drive map design. */
 typedef struct kconfig_options {
   uint32_t version[2];  /* Configuration file version. */
   uint8_t cmd_line[KERNEL_CMD_LINE_SIZE];  /* Kernel command line option string
                                             * terminated by a NULL character. */
   uint64_t kernel_len;  /* Size of the kernel. */
   uint64_t kernel_load_addr;  /* Load address in memory for the kernel image */
   uint64_t kernel_entry_addr;  /* Address to jump to after kernel is loaded. */
 } kconfig_options;
 
@@ skipping 184 matching lines @@
 int AddKernelKeySignature(KernelImage* image, const char* firmware_key_file);
 
 /* Add a kernel and kernel config signature to a kernel image [image]
  * using the private signing key in file [kernel_sigining_key_file].
  *
  * Return 1 on success, 0 on failure.
  */
 int AddKernelSignature(KernelImage* image,
                        const char* kernel_sigining_key_file);
 
+/* Returns the logical version of a kernel blob which is calculated as
+ * (kernel_key_version << 16 | kernel_version). */
+uint32_t GetLogicalKernelVersion(uint8_t* kernel_blob);
+
+#define  BOOT_KERNEL_A_CONTINUE 1
+#define  BOOT_KERNEL_B_CONTINUE 2
+#define  BOOT_KERNEL_RECOVERY_CONTINUE 3
+
+/* Contains information about the kernel paritition
+ * gleaned from the GPT partition table.
+ *
+ * Based on the Chromium OS Drive Map design document by
+ * rspangler@chromium.org.
+ *
+*/
+typedef struct kernel_entry {
+  uint8_t* kernel_blob;  /* Pointer to actual kernel. */
+  uint8_t boot_priority;  /* 15 = highest, 1 = lowest, 0 = not bootable. */
+  uint8_t boot_tries_remaining;  /* Used when boot_priority = 0. */
+  uint8_t boot_success_flag;  /* Set to 1 on successful boot by AU. */
+} kernel_entry;
+
+void PrintKernelEntry(kernel_entry* entry);
+
+/* This function is the driver used by the RW firmware to
+ * determine which copy of the kernel to boot from. It performs
+ * the requisite priority and remaining tries checking for a specific
+ * kernel partition, does rollback index checking, including updating
+ * if required.
+ *
+ * Returns the code path to follow. It is one of:
+ * BOOT_KERNEL_A_CONTINUE          Boot from Kenrel A
+ * BOOT_KERNEL_B_CONTINUE          Boot from Kernel B
+ * BOOT_KERNEL_RECOVERY_CONTINUE   Jump to recovery mode
+ */
+int VerifyKernelDriver_f(uint8_t* firmware_key_blob,
+                         kernel_entry* kernelA,
+                         kernel_entry* kernelB,
+                         int dev_mode);
+
 #endif  /* VBOOT_REFERENCE_KERNEL_IMAGE_H_ */