Address some security concerns in the cgpt tool.

cgpt/cmd_create.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.
 
 #include "cgpt.h"
 
 #include <getopt.h>
 #include <stdio.h>
 #include <stdlib.h>
 #include <string.h>
 #include <uuid/uuid.h>
 
 #include "cgptlib_internal.h"
 
 static void Usage(void)
 {
   printf("\nUsage: %s create [OPTIONS] DRIVE\n\n"
          "Create or reset an empty GPT.\n\n"
          "Options:\n"
          "  -z           Zero the sectors of the GPT table and entries\n"
          "\n", progname);
 }
 
 int cmd_create(int argc, char *argv[]) {
   struct drive drive;
   int zap = 0;
-  
+
   int c;
   int errorcnt = 0;
 
   opterr = 0;                     // quiet, you
   while ((c=getopt(argc, argv, ":hz")) != -1)
   {
     switch (c)
     {
     case 'z':
       zap = 1;
@@ skipping 31 matching lines @@
 
   // Erase the data
   memset(drive.gpt.primary_header, 0,
          drive.gpt.sector_bytes * GPT_HEADER_SECTOR);
   memset(drive.gpt.secondary_header, 0,
          drive.gpt.sector_bytes * GPT_HEADER_SECTOR);
   memset(drive.gpt.primary_entries, 0,
          drive.gpt.sector_bytes * GPT_ENTRIES_SECTORS);
   memset(drive.gpt.secondary_entries, 0,
          drive.gpt.sector_bytes * GPT_ENTRIES_SECTORS);
-  
+
   drive.gpt.modified |= (GPT_MODIFIED_HEADER1 | GPT_MODIFIED_ENTRIES1 |
                          GPT_MODIFIED_HEADER2 | GPT_MODIFIED_ENTRIES2);
 
   // Initialize a blank set
   if (!zap)
   {
     GptHeader *h = (GptHeader *)drive.gpt.primary_header;
     memcpy(h->signature, GPT_HEADER_SIGNATURE, GPT_HEADER_SIGNATURE_SIZE);
     h->revision = GPT_HEADER_REVISION;
     h->size = sizeof(GptHeader);
     h->my_lba = 1;
     h->alternate_lba = drive.gpt.drive_sectors - 1;
     h->first_usable_lba = 1 + 1 + GPT_ENTRIES_SECTORS;
     h->last_usable_lba = drive.gpt.drive_sectors - 1 - GPT_ENTRIES_SECTORS - 1;
     uuid_generate((uint8_t *)&h->disk_uuid);
     h->entries_lba = 2;
     h->number_of_entries = 128;
     h->size_of_entry = sizeof(GptEntry);
 
     // Copy to secondary
     RepairHeader(&drive.gpt, MASK_PRIMARY);
 
     UpdateCrc(&drive.gpt);
   }
 
   // Write it all out
   return DriveClose(&drive, 1);
 }