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 private_key private_key = {
  68         .refcnt = REF_INIT ( ref_no_free ),
  69         .builder = {
  70                 .data = private_key_data,
  71                 .len = ( ( size_t ) private_key_len ),
  72         },
  73 };
  74
  75 /** Default private key */
  76 static struct asn1_cursor default_private_key = {
  77         .data = private_key_data,
  78         .len = ( ( size_t ) private_key_len ),
  79 };
  80
  81 /** Private key setting */
  82 static struct setting privkey_setting __setting ( SETTING_CRYPTO, privkey ) = {
  83         .name = "privkey",
  84         .description = "Private key",
  85         .tag = DHCP_EB_KEY,
  86         .type = &setting_type_hex,
  87 };
  88
  89 /**
  90  * Free private key
  91  *
  92  * @v refcnt            Reference counter
  93  */
  94 void privkey_free ( struct refcnt *refcnt ) {
  95         struct private_key *key =
  96                 container_of ( refcnt, struct private_key, refcnt );
  97
  98         free ( key->builder.data );
  99         free ( key );
 100 }
 101
 102 /**
 103  * Apply private key configuration settings
 104  *
 105  * @ret rc              Return status code
 106  */
 107 static int privkey_apply_settings ( void ) {
 108         static void *key_data = NULL;
 109         int len;
 110
 111         /* Allow private key to be overridden only if not explicitly
 112          * specified at build time.
 113          */
 114         if ( ALLOW_KEY_OVERRIDE ) {
 115
 116                 /* Restore default private key */
 117                 memcpy ( &private_key.builder, &default_private_key,
 118                          sizeof ( private_key.builder ) );
 119
 120                 /* Fetch new private key, if any */
 121                 free ( key_data );
 122                 if ( ( len = fetch_raw_setting_copy ( NULL, &privkey_setting,
 123                                                       &key_data ) ) >= 0 ) {
 124                         private_key.builder.data = key_data;
 125                         private_key.builder.len = len;
 126                 }
 127         }
 128
 129         /* Debug */
 130         if ( private_key.builder.len ) {
 131                 DBGC ( &private_key, "PRIVKEY using %s private key:\n",
 132                        ( key_data ? "external" : "built-in" ) );
 133                 DBGC_HDA ( &private_key, 0, private_key.builder.data,
 134                            private_key.builder.len );
 135         } else {
 136                 DBGC ( &private_key, "PRIVKEY has no private key\n" );
 137         }
 138
 139         return 0;
 140 }
 141
 142 /** Private key settings applicator */
 143 struct settings_applicator privkey_applicator __settings_applicator = {
 144         .apply = privkey_apply_settings,
 145 };