Zero-out allocated buffer while creating kernel preamble header.

host/lib/host_common.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.
  *
  * Host functions for verified boot.
  */
 
 /* TODO: change all 'return 0', 'return 1' into meaningful return codes */
 
 #include "host_common.h"
@@ skipping 76 matching lines @@
   uint8_t* body_sig_dest;
   uint8_t* block_sig_dest;
   VbSignature *sigtmp;
 
   /* If the block size is smaller than the desired size, pad it */
   if (block_size < desired_size)
     block_size = desired_size;
 
   /* Allocate key block */
   h = (VbKernelPreambleHeader*)Malloc(block_size);
+  Memset(h, 0, block_size);
+
   if (!h)
     return NULL;
   body_sig_dest = (uint8_t*)(h + 1);
   block_sig_dest = body_sig_dest + body_signature->sig_size;
 
   h->header_version_major = KERNEL_PREAMBLE_HEADER_VERSION_MAJOR;
   h->header_version_minor = KERNEL_PREAMBLE_HEADER_VERSION_MINOR;
   h->preamble_size = block_size;
   h->kernel_version = kernel_version;
   h->body_load_address = body_load_address;
@@ skipping 10 matching lines @@
                 siglen_map[signing_key->algorithm], signed_size);
 
   /* Calculate signature */
   sigtmp = CalculateSignature((uint8_t*)h, signed_size, signing_key);
   SignatureCopy(&h->preamble_signature, sigtmp);
   Free(sigtmp);
 
   /* Return the header */
   return h;
 }