Pass VbSharedData between LoadFirmware() and LoadKernel()

firmware/lib/vboot_common.c

-/* Copyright (c) 2010 The Chromium OS Authors. All rights reserved.
+/* 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.
  *
  * Common functions between firmware and kernel verified boot.
  * (Firmware portion)
  */
 
 
 #include "vboot_common.h"
 #include "utility.h"
 
 
 char* kVbootErrors[VBOOT_ERROR_MAX] = {
   "Success.",
   "Key block invalid.",
   "Key block signature failed.",
   "Key block hash failed.",
   "Public key invalid.",
   "Preamble invalid.",
   "Preamble signature check failed.",
+  "Shared data invalid."
 };
 
 
 uint64_t OffsetOf(const void *base, const void *ptr) {
   return (uint64_t)(size_t)ptr - (uint64_t)(size_t)base;
 }
 
 
 /* Helper functions to get data pointed to by a public key or signature. */
 uint8_t* GetPublicKeyData(VbPublicKey* key) {
@@ skipping 338 matching lines @@
   /* Verify body signature is inside the block */
   if (VerifySignatureInside(preamble, preamble->preamble_size,
                             &preamble->body_signature)) {
     VBDEBUG(("Kernel body signature off end of preamble\n"));
     return VBOOT_PREAMBLE_INVALID;
   }
 
   /* Success */
   return VBOOT_SUCCESS;
 }
+
+
+int VbSharedDataInit(VbSharedDataHeader* header, uint64_t size) {
+  if (size < sizeof(VbSharedDataHeader)) {
+    VBDEBUG(("Not enough data for header.\n"));
+    return VBOOT_SHARED_DATA_INVALID;
+  }
+
+  if (!header)
+    return VBOOT_SHARED_DATA_INVALID;
+
+  /* Zero the header */
+  Memset(header, 0, sizeof(VbSharedDataHeader));
+
+  /* Initialize fields */
+  header->struct_version = VB_SHARED_DATA_VERSION;
+  header->struct_size = sizeof(VbSharedDataHeader);
+  header->data_size = size;
+  header->data_used = sizeof(VbSharedDataHeader);

[Bill Richardson, 2011/03/09 20:52:20]

What is the relationship between data_size and data_used? Shouldn't there be
some check that the size arg is valid?

[Randall Spangler, 2011/03/09 21:11:35]

There is.  See the first if() in this func.
size is the entire buffer size.  used is how much of it we've used so far.  Will
expand on comments.

+
+  /* Success */
+  return VBOOT_SUCCESS;
+}
+
+
+uint64_t VbSharedDataReserve(VbSharedDataHeader* header, uint64_t size) {
+  uint64_t offs = header->data_used;
+
+  if (!header || size > header->data_size - header->data_used)
+    return 0;  /* Not initialize, or not enough space left. */
+  header->data_used += size;
+  return offs;
+}
+
+
+int VbSharedDataSetKernelKey(VbSharedDataHeader* header,
+                             const VbPublicKey* src) {
+
+  VbPublicKey *kdest = &header->kernel_subkey;
+
+  if (!header)
+    return VBOOT_SHARED_DATA_INVALID;
+
+  /* Attempt to allocate space for the key, if it hasn't been allocated yet */
+  if (!header->kernel_subkey_data_offset) {
+    header->kernel_subkey_data_offset = VbSharedDataReserve(header,
+                                                          src->key_size);
+    if (!header->kernel_subkey_data_offset)
+      return VBOOT_SHARED_DATA_INVALID;
+    header->kernel_subkey_data_size = src->key_size;
+  }
+
+  /* Copy the kernel sign key blob into the destination buffer */
+  PublicKeyInit(kdest, (uint8_t*)header + header->kernel_subkey_data_offset,
+                header->kernel_subkey_data_size);
+
+  return PublicKeyCopy(kdest, src);
+}