module/icp/algs/modes/gcm_generic.c

   1 /*
   2  * CDDL HEADER START
   3  *
   4  * The contents of this file are subject to the terms of the
   5  * Common Development and Distribution License (the "License").
   6  * You may not use this file except in compliance with the License.
   7  *
   8  * You can obtain a copy of the license at usr/src/OPENSOLARIS.LICENSE
   9  * or https://opensource.org/licenses/CDDL-1.0.
  10  * See the License for the specific language governing permissions
  11  * and limitations under the License.
  12  *
  13  * When distributing Covered Code, include this CDDL HEADER in each
  14  * file and include the License file at usr/src/OPENSOLARIS.LICENSE.
  15  * If applicable, add the following below this CDDL HEADER, with the
  16  * fields enclosed by brackets "[]" replaced with your own identifying
  17  * information: Portions Copyright [yyyy] [name of copyright owner]
  18  *
  19  * CDDL HEADER END
  20  */
  21 /*
  22  * Copyright (c) 2003, 2010, Oracle and/or its affiliates. All rights reserved.
  23  */
  24
  25 #include <modes/gcm_impl.h>
  26
  27 struct aes_block {
  28         uint64_t a;
  29         uint64_t b;
  30 };
  31
  32 /*
  33  * Perform a carry-less multiplication (that is, use XOR instead of the
  34  * multiply operator) on *x_in and *y and place the result in *res.
  35  *
  36  * Byte swap the input (*x_in and *y) and the output (*res).
  37  *
  38  * Note: x_in, y, and res all point to 16-byte numbers (an array of two
  39  * 64-bit integers).
  40  */
  41 static void
  42 gcm_generic_mul(uint64_t *x_in, uint64_t *y, uint64_t *res)
  43 {
  44         static const uint64_t R = 0xe100000000000000ULL;
  45         struct aes_block z = {0, 0};
  46         struct aes_block v;
  47         uint64_t x;
  48         int i, j;
  49
  50         v.a = ntohll(y[0]);
  51         v.b = ntohll(y[1]);
  52
  53         for (j = 0; j < 2; j++) {
  54                 x = ntohll(x_in[j]);
  55                 for (i = 0; i < 64; i++, x <<= 1) {
  56                         if (x & 0x8000000000000000ULL) {
  57                                 z.a ^= v.a;
  58                                 z.b ^= v.b;
  59                         }
  60                         if (v.b & 1ULL) {
  61                                 v.b = (v.a << 63)|(v.b >> 1);
  62                                 v.a = (v.a >> 1) ^ R;
  63                         } else {
  64                                 v.b = (v.a << 63)|(v.b >> 1);
  65                                 v.a = v.a >> 1;
  66                         }
  67                 }
  68         }
  69         res[0] = htonll(z.a);
  70         res[1] = htonll(z.b);
  71 }
  72
  73 static boolean_t
  74 gcm_generic_will_work(void)
  75 {
  76         return (B_TRUE);
  77 }
  78
  79 const gcm_impl_ops_t gcm_generic_impl = {
  80         .mul = &gcm_generic_mul,
  81         .is_supported = &gcm_generic_will_work,
  82         .name = "generic"
  83 };