src/crypto/privkey.c

   1 /*
   2  * Copyright (C) 2012 Michael Brown <mbrown@fensystems.co.uk>.
   3  *
   4  * This program is free software; you can redistribute it and/or
   5  * modify it under the terms of the GNU General Public License as
   6  * published by the Free Software Foundation; either version 2 of the
   7  * License, or any later version.
   8  *
   9  * This program is distributed in the hope that it will be useful, but
  10  * WITHOUT ANY WARRANTY; without even the implied warranty of
  11  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
  12  * General Public License for more details.
  13  *
  14  * You should have received a copy of the GNU General Public License
  15  * along with this program; if not, write to the Free Software
  16  * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA
  17  * 02110-1301, USA.
  18  *
  19  * You can also choose to distribute this program under the terms of
  20  * the Unmodified Binary Distribution Licence (as given in the file
  21  * COPYING.UBDL), provided that you have satisfied its requirements.
  22  */
  23
  24 FILE_LICENCE ( GPL2_OR_LATER_OR_UBDL );
  25
  26 #include <stdint.h>
  27 #include <stdlib.h>
  28 #include <string.h>
  29 #include <ipxe/dhcp.h>
  30 #include <ipxe/settings.h>
  31 #include <ipxe/x509.h>
  32 #include <ipxe/privkey.h>
  33
  34 /** @file
  35  *
  36  * Private key
  37  *
  38  * Life would in theory be easier if we could use a single file to
  39  * hold both the certificate and corresponding private key.
  40  * Unfortunately, the only common format which supports this is
  41  * PKCS#12 (aka PFX), which is too ugly to be allowed anywhere near my
  42  * codebase.  See, for reference and amusement:
  43  *
  44  *    http://www.cs.auckland.ac.nz/~pgut001/pubs/pfx.html
  45  */
  46
  47 /* Allow private key to be overridden if not explicitly specified */
  48 #ifdef PRIVATE_KEY
  49 #define ALLOW_KEY_OVERRIDE 0
  50 #else
  51 #define ALLOW_KEY_OVERRIDE 1
  52 #endif
  53
  54 /* Raw private key data */
  55 extern char private_key_data[];
  56 extern char private_key_len[];
  57 __asm__ ( ".section \".rodata\", \"a\", " PROGBITS "\n\t"
  58           "\nprivate_key_data:\n\t"
  59 #ifdef PRIVATE_KEY
  60           ".incbin \"" PRIVATE_KEY "\"\n\t"
  61 #endif /* PRIVATE_KEY */
  62           ".size private_key_data, ( . - private_key_data )\n\t"
  63           ".equ private_key_len, ( . - private_key_data )\n\t"
  64           ".previous\n\t" );
  65
  66 /** Private key */
  67 struct asn1_cursor private_key = {
  68         .data = private_key_data,
  69         .len = ( ( size_t ) private_key_len ),
  70 };
  71
  72 /** Default private key */
  73 static struct asn1_cursor default_private_key = {
  74         .data = private_key_data,
  75         .len = ( ( size_t ) private_key_len ),
  76 };
  77
  78 /** Private key setting */
  79 static struct setting privkey_setting __setting ( SETTING_CRYPTO, privkey ) = {
  80         .name = "privkey",
  81         .description = "Private key",
  82         .tag = DHCP_EB_KEY,
  83         .type = &setting_type_hex,
  84 };
  85
  86 /**
  87  * Apply private key configuration settings
  88  *
  89  * @ret rc              Return status code
  90  */
  91 static int privkey_apply_settings ( void ) {
  92         static void *key_data = NULL;
  93         int len;
  94
  95         /* Allow private key to be overridden only if not explicitly
  96          * specified at build time.
  97          */
  98         if ( ALLOW_KEY_OVERRIDE ) {
  99
 100                 /* Restore default private key */
 101                 memcpy ( &private_key, &default_private_key,
 102                          sizeof ( private_key ) );
 103
 104                 /* Fetch new private key, if any */
 105                 free ( key_data );
 106                 if ( ( len = fetch_raw_setting_copy ( NULL, &privkey_setting,
 107                                                       &key_data ) ) >= 0 ) {
 108                         private_key.data = key_data;
 109                         private_key.len = len;
 110                 }
 111         }
 112
 113         /* Debug */
 114         if ( private_key.len ) {
 115                 DBGC ( &private_key, "PRIVKEY using %s private key:\n",
 116                        ( key_data ? "external" : "built-in" ) );
 117                 DBGC_HDA ( &private_key, 0, private_key.data, private_key.len );
 118         } else {
 119                 DBGC ( &private_key, "PRIVKEY has no private key\n" );
 120         }
 121
 122         return 0;
 123 }
 124
 125 /** Private key settings applicator */
 126 struct settings_applicator privkey_applicator __settings_applicator = {
 127         .apply = privkey_apply_settings,
 128 };