certs/common.c

   1 // SPDX-License-Identifier: GPL-2.0-or-later
   2
   3 #include <linux/kernel.h>
   4 #include <linux/key.h>
   5 #include "common.h"
   6
   7 int load_certificate_list(const u8 cert_list[],
   8                           const unsigned long list_size,
   9                           const struct key *keyring)
  10 {
  11         key_ref_t key;
  12         const u8 *p, *end;
  13         size_t plen;
  14
  15         p = cert_list;
  16         end = p + list_size;
  17         while (p < end) {
  18                 /* Each cert begins with an ASN.1 SEQUENCE tag and must be more
  19                  * than 256 bytes in size.
  20                  */
  21                 if (end - p < 4)
  22                         goto dodgy_cert;
  23                 if (p[0] != 0x30 &&
  24                     p[1] != 0x82)
  25                         goto dodgy_cert;
  26                 plen = (p[2] << 8) | p[3];
  27                 plen += 4;
  28                 if (plen > end - p)
  29                         goto dodgy_cert;
  30
  31                 key = key_create_or_update(make_key_ref(keyring, 1),
  32                                            "asymmetric",
  33                                            NULL,
  34                                            p,
  35                                            plen,
  36                                            ((KEY_POS_ALL & ~KEY_POS_SETATTR) |
  37                                            KEY_USR_VIEW | KEY_USR_READ),
  38                                            KEY_ALLOC_NOT_IN_QUOTA |
  39                                            KEY_ALLOC_BUILT_IN |
  40                                            KEY_ALLOC_BYPASS_RESTRICTION);
  41                 if (IS_ERR(key)) {
  42                         pr_err("Problem loading in-kernel X.509 certificate (%ld)\n",
  43                                PTR_ERR(key));
  44                 } else {
  45                         pr_notice("Loaded X.509 cert '%s'\n",
  46                                   key_ref_to_ptr(key)->description);
  47                         key_ref_put(key);
  48                 }
  49                 p += plen;
  50         }
  51
  52         return 0;
  53
  54 dodgy_cert:
  55         pr_err("Problem parsing in-kernel X.509 certificate list\n");
  56         return 0;
  57 }