src/usr/imgtrust.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 <stdlib.h>
  27 #include <errno.h>
  28 #include <time.h>
  29 #include <syslog.h>
  30 #include <ipxe/uaccess.h>
  31 #include <ipxe/image.h>
  32 #include <ipxe/cms.h>
  33 #include <ipxe/validator.h>
  34 #include <ipxe/monojob.h>
  35 #include <usr/imgtrust.h>
  36
  37 /** @file
  38  *
  39  * Image trust management
  40  *
  41  */
  42
  43 /**
  44  * Verify image using downloaded signature
  45  *
  46  * @v image             Image to verify
  47  * @v signature         Image containing signature
  48  * @v name              Required common name, or NULL to allow any name
  49  * @ret rc              Return status code
  50  */
  51 int imgverify ( struct image *image, struct image *signature,
  52                 const char *name ) {
  53         size_t len;
  54         void *data;
  55         struct cms_signature *sig;
  56         struct cms_signer_info *info;
  57         time_t now;
  58         int rc;
  59
  60         /* Mark image as untrusted */
  61         image_untrust ( image );
  62
  63         /* Copy signature to internal memory */
  64         len = signature->len;
  65         data = malloc ( len );
  66         if ( ! data ) {
  67                 rc = -ENOMEM;
  68                 goto err_alloc;
  69         }
  70         copy_from_user ( data, signature->data, 0, len );
  71
  72         /* Parse signature */
  73         if ( ( rc = cms_signature ( data, len, &sig ) ) != 0 )
  74                 goto err_parse;
  75
  76         /* Free internal copy of signature */
  77         free ( data );
  78         data = NULL;
  79
  80         /* Complete all certificate chains */
  81         list_for_each_entry ( info, &sig->info, list ) {
  82                 if ( ( rc = create_validator ( &monojob, info->chain ) ) != 0 )
  83                         goto err_create_validator;
  84                 if ( ( rc = monojob_wait ( NULL, 0 ) ) != 0 )
  85                         goto err_validator_wait;
  86         }
  87
  88         /* Use signature to verify image */
  89         now = time ( NULL );
  90         if ( ( rc = cms_verify ( sig, image->data, image->len,
  91                                  name, now, NULL, NULL ) ) != 0 )
  92                 goto err_verify;
  93
  94         /* Drop reference to signature */
  95         cms_put ( sig );
  96         sig = NULL;
  97
  98         /* Mark image as trusted */
  99         image_trust ( image );
 100         syslog ( LOG_NOTICE, "Image \"%s\" signature OK\n", image->name );
 101
 102         return 0;
 103
 104  err_verify:
 105  err_validator_wait:
 106  err_create_validator:
 107         cms_put ( sig );
 108  err_parse:
 109         free ( data );
 110  err_alloc:
 111         syslog ( LOG_ERR, "Image \"%s\" signature bad: %s\n",
 112                  image->name, strerror ( rc ) );
 113         return rc;
 114 }