kernel/system_keyring.c

   1 /* System trusted keyring for trusted public keys
   2  *
   3  * Copyright (C) 2012 Red Hat, Inc. All Rights Reserved.
   4  * Written by David Howells (dhowells@redhat.com)
   5  *
   6  * This program is free software; you can redistribute it and/or
   7  * modify it under the terms of the GNU General Public Licence
   8  * as published by the Free Software Foundation; either version
   9  * 2 of the Licence, or (at your option) any later version.
  10  */
  11
  12 #include <linux/export.h>
  13 #include <linux/kernel.h>
  14 #include <linux/sched.h>
  15 #include <linux/cred.h>
  16 #include <linux/err.h>
  17 #include <keys/asymmetric-type.h>
  18 #include <keys/system_keyring.h>
  19 #include "module-internal.h"
  20
  21 struct key *system_trusted_keyring;
  22 EXPORT_SYMBOL_GPL(system_trusted_keyring);
  23
  24 extern __initconst const u8 system_certificate_list[];
  25 extern __initconst const u8 system_certificate_list_end[];
  26
  27 /*
  28  * Load the compiled-in keys
  29  */
  30 static __init int system_trusted_keyring_init(void)
  31 {
  32         pr_notice("Initialise system trusted keyring\n");
  33
  34         system_trusted_keyring =
  35                 keyring_alloc(".system_keyring",
  36                               KUIDT_INIT(0), KGIDT_INIT(0), current_cred(),
  37                               ((KEY_POS_ALL & ~KEY_POS_SETATTR) |
  38                                KEY_USR_VIEW | KEY_USR_READ),
  39                               KEY_ALLOC_NOT_IN_QUOTA, NULL);
  40         if (IS_ERR(system_trusted_keyring))
  41                 panic("Can't allocate system trusted keyring\n");
  42
  43         return 0;
  44 }
  45
  46 /*
  47  * Must be initialised before we try and load the keys into the keyring.
  48  */
  49 device_initcall(system_trusted_keyring_init);
  50
  51 /*
  52  * Load the compiled-in list of X.509 certificates.
  53  */
  54 static __init int load_system_certificate_list(void)
  55 {
  56         key_ref_t key;
  57         const u8 *p, *end;
  58         size_t plen;
  59
  60         pr_notice("Loading compiled-in X.509 certificates\n");
  61
  62         end = system_certificate_list_end;
  63         p = system_certificate_list;
  64         while (p < end) {
  65                 /* Each cert begins with an ASN.1 SEQUENCE tag and must be more
  66                  * than 256 bytes in size.
  67                  */
  68                 if (end - p < 4)
  69                         goto dodgy_cert;
  70                 if (p[0] != 0x30 &&
  71                     p[1] != 0x82)
  72                         goto dodgy_cert;
  73                 plen = (p[2] << 8) | p[3];
  74                 plen += 4;
  75                 if (plen > end - p)
  76                         goto dodgy_cert;
  77
  78                 key = key_create_or_update(make_key_ref(system_trusted_keyring, 1),
  79                                            "asymmetric",
  80                                            NULL,
  81                                            p,
  82                                            plen,
  83                                            (KEY_POS_ALL & ~KEY_POS_SETATTR) |
  84                                            KEY_USR_VIEW,
  85                                            KEY_ALLOC_NOT_IN_QUOTA);
  86                 if (IS_ERR(key)) {
  87                         pr_err("Problem loading in-kernel X.509 certificate (%ld)\n",
  88                                PTR_ERR(key));
  89                 } else {
  90                         pr_notice("Loaded X.509 cert '%s'\n",
  91                                   key_ref_to_ptr(key)->description);
  92                         key_ref_put(key);
  93                 }
  94                 p += plen;
  95         }
  96
  97         return 0;
  98
  99 dodgy_cert:
 100         pr_err("Problem parsing in-kernel X.509 certificate list\n");
 101         return 0;
 102 }
 103 late_initcall(load_system_certificate_list);