+++ /dev/null
-/* gf128mul.c - GF(2^128) multiplication functions
- *
- * Copyright (c) 2003, Dr Brian Gladman, Worcester, UK.
- * Copyright (c) 2006, Rik Snel <rsnel@cube.dyndns.org>
- *
- * Based on Dr Brian Gladman's (GPL'd) work published at
- * http://gladman.plushost.co.uk/oldsite/cryptography_technology/index.php
- * See the original copyright notice below.
- *
- * This program is free software; you can redistribute it and/or modify it
- * under the terms of the GNU General Public License as published by the Free
- * Software Foundation; either version 2 of the License, or (at your option)
- * any later version.
- */
-
-/*
- ---------------------------------------------------------------------------
- Copyright (c) 2003, Dr Brian Gladman, Worcester, UK. All rights reserved.
-
- LICENSE TERMS
-
- The free distribution and use of this software in both source and binary
- form is allowed (with or without changes) provided that:
-
- 1. distributions of this source code include the above copyright
- notice, this list of conditions and the following disclaimer;
-
- 2. distributions in binary form include the above copyright
- notice, this list of conditions and the following disclaimer
- in the documentation and/or other associated materials;
-
- 3. the copyright holder's name is not used to endorse products
- built using this software without specific written permission.
-
- ALTERNATIVELY, provided that this notice is retained in full, this product
- may be distributed under the terms of the GNU General Public License (GPL),
- in which case the provisions of the GPL apply INSTEAD OF those given above.
-
- DISCLAIMER
-
- This software is provided 'as is' with no explicit or implied warranties
- in respect of its properties, including, but not limited to, correctness
- and/or fitness for purpose.
- ---------------------------------------------------------------------------
- Issue 31/01/2006
-
- This file provides fast multiplication in GF(2^128) as required by several
- cryptographic authentication modes
-*/
-
-#include <crypto/gf128mul.h>
-#include <linux/kernel.h>
-#include <linux/module.h>
-#include <linux/slab.h>
-
-#define gf128mul_dat(q) { \
- q(0x00), q(0x01), q(0x02), q(0x03), q(0x04), q(0x05), q(0x06), q(0x07),\
- q(0x08), q(0x09), q(0x0a), q(0x0b), q(0x0c), q(0x0d), q(0x0e), q(0x0f),\
- q(0x10), q(0x11), q(0x12), q(0x13), q(0x14), q(0x15), q(0x16), q(0x17),\
- q(0x18), q(0x19), q(0x1a), q(0x1b), q(0x1c), q(0x1d), q(0x1e), q(0x1f),\
- q(0x20), q(0x21), q(0x22), q(0x23), q(0x24), q(0x25), q(0x26), q(0x27),\
- q(0x28), q(0x29), q(0x2a), q(0x2b), q(0x2c), q(0x2d), q(0x2e), q(0x2f),\
- q(0x30), q(0x31), q(0x32), q(0x33), q(0x34), q(0x35), q(0x36), q(0x37),\
- q(0x38), q(0x39), q(0x3a), q(0x3b), q(0x3c), q(0x3d), q(0x3e), q(0x3f),\
- q(0x40), q(0x41), q(0x42), q(0x43), q(0x44), q(0x45), q(0x46), q(0x47),\
- q(0x48), q(0x49), q(0x4a), q(0x4b), q(0x4c), q(0x4d), q(0x4e), q(0x4f),\
- q(0x50), q(0x51), q(0x52), q(0x53), q(0x54), q(0x55), q(0x56), q(0x57),\
- q(0x58), q(0x59), q(0x5a), q(0x5b), q(0x5c), q(0x5d), q(0x5e), q(0x5f),\
- q(0x60), q(0x61), q(0x62), q(0x63), q(0x64), q(0x65), q(0x66), q(0x67),\
- q(0x68), q(0x69), q(0x6a), q(0x6b), q(0x6c), q(0x6d), q(0x6e), q(0x6f),\
- q(0x70), q(0x71), q(0x72), q(0x73), q(0x74), q(0x75), q(0x76), q(0x77),\
- q(0x78), q(0x79), q(0x7a), q(0x7b), q(0x7c), q(0x7d), q(0x7e), q(0x7f),\
- q(0x80), q(0x81), q(0x82), q(0x83), q(0x84), q(0x85), q(0x86), q(0x87),\
- q(0x88), q(0x89), q(0x8a), q(0x8b), q(0x8c), q(0x8d), q(0x8e), q(0x8f),\
- q(0x90), q(0x91), q(0x92), q(0x93), q(0x94), q(0x95), q(0x96), q(0x97),\
- q(0x98), q(0x99), q(0x9a), q(0x9b), q(0x9c), q(0x9d), q(0x9e), q(0x9f),\
- q(0xa0), q(0xa1), q(0xa2), q(0xa3), q(0xa4), q(0xa5), q(0xa6), q(0xa7),\
- q(0xa8), q(0xa9), q(0xaa), q(0xab), q(0xac), q(0xad), q(0xae), q(0xaf),\
- q(0xb0), q(0xb1), q(0xb2), q(0xb3), q(0xb4), q(0xb5), q(0xb6), q(0xb7),\
- q(0xb8), q(0xb9), q(0xba), q(0xbb), q(0xbc), q(0xbd), q(0xbe), q(0xbf),\
- q(0xc0), q(0xc1), q(0xc2), q(0xc3), q(0xc4), q(0xc5), q(0xc6), q(0xc7),\
- q(0xc8), q(0xc9), q(0xca), q(0xcb), q(0xcc), q(0xcd), q(0xce), q(0xcf),\
- q(0xd0), q(0xd1), q(0xd2), q(0xd3), q(0xd4), q(0xd5), q(0xd6), q(0xd7),\
- q(0xd8), q(0xd9), q(0xda), q(0xdb), q(0xdc), q(0xdd), q(0xde), q(0xdf),\
- q(0xe0), q(0xe1), q(0xe2), q(0xe3), q(0xe4), q(0xe5), q(0xe6), q(0xe7),\
- q(0xe8), q(0xe9), q(0xea), q(0xeb), q(0xec), q(0xed), q(0xee), q(0xef),\
- q(0xf0), q(0xf1), q(0xf2), q(0xf3), q(0xf4), q(0xf5), q(0xf6), q(0xf7),\
- q(0xf8), q(0xf9), q(0xfa), q(0xfb), q(0xfc), q(0xfd), q(0xfe), q(0xff) \
-}
-
-/*
- * Given a value i in 0..255 as the byte overflow when a field element
- * in GF(2^128) is multiplied by x^8, the following macro returns the
- * 16-bit value that must be XOR-ed into the low-degree end of the
- * product to reduce it modulo the polynomial x^128 + x^7 + x^2 + x + 1.
- *
- * There are two versions of the macro, and hence two tables: one for
- * the "be" convention where the highest-order bit is the coefficient of
- * the highest-degree polynomial term, and one for the "le" convention
- * where the highest-order bit is the coefficient of the lowest-degree
- * polynomial term. In both cases the values are stored in CPU byte
- * endianness such that the coefficients are ordered consistently across
- * bytes, i.e. in the "be" table bits 15..0 of the stored value
- * correspond to the coefficients of x^15..x^0, and in the "le" table
- * bits 15..0 correspond to the coefficients of x^0..x^15.
- *
- * Therefore, provided that the appropriate byte endianness conversions
- * are done by the multiplication functions (and these must be in place
- * anyway to support both little endian and big endian CPUs), the "be"
- * table can be used for multiplications of both "bbe" and "ble"
- * elements, and the "le" table can be used for multiplications of both
- * "lle" and "lbe" elements.
- */
-
-#define xda_be(i) ( \
- (i & 0x80 ? 0x4380 : 0) ^ (i & 0x40 ? 0x21c0 : 0) ^ \
- (i & 0x20 ? 0x10e0 : 0) ^ (i & 0x10 ? 0x0870 : 0) ^ \
- (i & 0x08 ? 0x0438 : 0) ^ (i & 0x04 ? 0x021c : 0) ^ \
- (i & 0x02 ? 0x010e : 0) ^ (i & 0x01 ? 0x0087 : 0) \
-)
-
-#define xda_le(i) ( \
- (i & 0x80 ? 0xe100 : 0) ^ (i & 0x40 ? 0x7080 : 0) ^ \
- (i & 0x20 ? 0x3840 : 0) ^ (i & 0x10 ? 0x1c20 : 0) ^ \
- (i & 0x08 ? 0x0e10 : 0) ^ (i & 0x04 ? 0x0708 : 0) ^ \
- (i & 0x02 ? 0x0384 : 0) ^ (i & 0x01 ? 0x01c2 : 0) \
-)
-
-static const u16 gf128mul_table_le[256] = gf128mul_dat(xda_le);
-static const u16 gf128mul_table_be[256] = gf128mul_dat(xda_be);
-
-/*
- * The following functions multiply a field element by x^8 in
- * the polynomial field representation. They use 64-bit word operations
- * to gain speed but compensate for machine endianness and hence work
- * correctly on both styles of machine.
- */
-
-static void gf128mul_x8_lle(be128 *x)
-{
- u64 a = be64_to_cpu(x->a);
- u64 b = be64_to_cpu(x->b);
- u64 _tt = gf128mul_table_le[b & 0xff];
-
- x->b = cpu_to_be64((b >> 8) | (a << 56));
- x->a = cpu_to_be64((a >> 8) ^ (_tt << 48));
-}
-
-static void gf128mul_x8_bbe(be128 *x)
-{
- u64 a = be64_to_cpu(x->a);
- u64 b = be64_to_cpu(x->b);
- u64 _tt = gf128mul_table_be[a >> 56];
-
- x->a = cpu_to_be64((a << 8) | (b >> 56));
- x->b = cpu_to_be64((b << 8) ^ _tt);
-}
-
-void gf128mul_x8_ble(le128 *r, const le128 *x)
-{
- u64 a = le64_to_cpu(x->a);
- u64 b = le64_to_cpu(x->b);
- u64 _tt = gf128mul_table_be[a >> 56];
-
- r->a = cpu_to_le64((a << 8) | (b >> 56));
- r->b = cpu_to_le64((b << 8) ^ _tt);
-}
-EXPORT_SYMBOL(gf128mul_x8_ble);
-
-void gf128mul_lle(be128 *r, const be128 *b)
-{
- be128 p[8];
- int i;
-
- p[0] = *r;
- for (i = 0; i < 7; ++i)
- gf128mul_x_lle(&p[i + 1], &p[i]);
-
- memset(r, 0, sizeof(*r));
- for (i = 0;;) {
- u8 ch = ((u8 *)b)[15 - i];
-
- if (ch & 0x80)
- be128_xor(r, r, &p[0]);
- if (ch & 0x40)
- be128_xor(r, r, &p[1]);
- if (ch & 0x20)
- be128_xor(r, r, &p[2]);
- if (ch & 0x10)
- be128_xor(r, r, &p[3]);
- if (ch & 0x08)
- be128_xor(r, r, &p[4]);
- if (ch & 0x04)
- be128_xor(r, r, &p[5]);
- if (ch & 0x02)
- be128_xor(r, r, &p[6]);
- if (ch & 0x01)
- be128_xor(r, r, &p[7]);
-
- if (++i >= 16)
- break;
-
- gf128mul_x8_lle(r);
- }
-}
-EXPORT_SYMBOL(gf128mul_lle);
-
-void gf128mul_bbe(be128 *r, const be128 *b)
-{
- be128 p[8];
- int i;
-
- p[0] = *r;
- for (i = 0; i < 7; ++i)
- gf128mul_x_bbe(&p[i + 1], &p[i]);
-
- memset(r, 0, sizeof(*r));
- for (i = 0;;) {
- u8 ch = ((u8 *)b)[i];
-
- if (ch & 0x80)
- be128_xor(r, r, &p[7]);
- if (ch & 0x40)
- be128_xor(r, r, &p[6]);
- if (ch & 0x20)
- be128_xor(r, r, &p[5]);
- if (ch & 0x10)
- be128_xor(r, r, &p[4]);
- if (ch & 0x08)
- be128_xor(r, r, &p[3]);
- if (ch & 0x04)
- be128_xor(r, r, &p[2]);
- if (ch & 0x02)
- be128_xor(r, r, &p[1]);
- if (ch & 0x01)
- be128_xor(r, r, &p[0]);
-
- if (++i >= 16)
- break;
-
- gf128mul_x8_bbe(r);
- }
-}
-EXPORT_SYMBOL(gf128mul_bbe);
-
-/* This version uses 64k bytes of table space.
- A 16 byte buffer has to be multiplied by a 16 byte key
- value in GF(2^128). If we consider a GF(2^128) value in
- the buffer's lowest byte, we can construct a table of
- the 256 16 byte values that result from the 256 values
- of this byte. This requires 4096 bytes. But we also
- need tables for each of the 16 higher bytes in the
- buffer as well, which makes 64 kbytes in total.
-*/
-/* additional explanation
- * t[0][BYTE] contains g*BYTE
- * t[1][BYTE] contains g*x^8*BYTE
- * ..
- * t[15][BYTE] contains g*x^120*BYTE */
-struct gf128mul_64k *gf128mul_init_64k_bbe(const be128 *g)
-{
- struct gf128mul_64k *t;
- int i, j, k;
-
- t = kzalloc(sizeof(*t), GFP_KERNEL);
- if (!t)
- goto out;
-
- for (i = 0; i < 16; i++) {
- t->t[i] = kzalloc(sizeof(*t->t[i]), GFP_KERNEL);
- if (!t->t[i]) {
- gf128mul_free_64k(t);
- t = NULL;
- goto out;
- }
- }
-
- t->t[0]->t[1] = *g;
- for (j = 1; j <= 64; j <<= 1)
- gf128mul_x_bbe(&t->t[0]->t[j + j], &t->t[0]->t[j]);
-
- for (i = 0;;) {
- for (j = 2; j < 256; j += j)
- for (k = 1; k < j; ++k)
- be128_xor(&t->t[i]->t[j + k],
- &t->t[i]->t[j], &t->t[i]->t[k]);
-
- if (++i >= 16)
- break;
-
- for (j = 128; j > 0; j >>= 1) {
- t->t[i]->t[j] = t->t[i - 1]->t[j];
- gf128mul_x8_bbe(&t->t[i]->t[j]);
- }
- }
-
-out:
- return t;
-}
-EXPORT_SYMBOL(gf128mul_init_64k_bbe);
-
-void gf128mul_free_64k(struct gf128mul_64k *t)
-{
- int i;
-
- for (i = 0; i < 16; i++)
- kfree_sensitive(t->t[i]);
- kfree_sensitive(t);
-}
-EXPORT_SYMBOL(gf128mul_free_64k);
-
-void gf128mul_64k_bbe(be128 *a, const struct gf128mul_64k *t)
-{
- u8 *ap = (u8 *)a;
- be128 r[1];
- int i;
-
- *r = t->t[0]->t[ap[15]];
- for (i = 1; i < 16; ++i)
- be128_xor(r, r, &t->t[i]->t[ap[15 - i]]);
- *a = *r;
-}
-EXPORT_SYMBOL(gf128mul_64k_bbe);
-
-/* This version uses 4k bytes of table space.
- A 16 byte buffer has to be multiplied by a 16 byte key
- value in GF(2^128). If we consider a GF(2^128) value in a
- single byte, we can construct a table of the 256 16 byte
- values that result from the 256 values of this byte.
- This requires 4096 bytes. If we take the highest byte in
- the buffer and use this table to get the result, we then
- have to multiply by x^120 to get the final value. For the
- next highest byte the result has to be multiplied by x^112
- and so on. But we can do this by accumulating the result
- in an accumulator starting with the result for the top
- byte. We repeatedly multiply the accumulator value by
- x^8 and then add in (i.e. xor) the 16 bytes of the next
- lower byte in the buffer, stopping when we reach the
- lowest byte. This requires a 4096 byte table.
-*/
-struct gf128mul_4k *gf128mul_init_4k_lle(const be128 *g)
-{
- struct gf128mul_4k *t;
- int j, k;
-
- t = kzalloc(sizeof(*t), GFP_KERNEL);
- if (!t)
- goto out;
-
- t->t[128] = *g;
- for (j = 64; j > 0; j >>= 1)
- gf128mul_x_lle(&t->t[j], &t->t[j+j]);
-
- for (j = 2; j < 256; j += j)
- for (k = 1; k < j; ++k)
- be128_xor(&t->t[j + k], &t->t[j], &t->t[k]);
-
-out:
- return t;
-}
-EXPORT_SYMBOL(gf128mul_init_4k_lle);
-
-struct gf128mul_4k *gf128mul_init_4k_bbe(const be128 *g)
-{
- struct gf128mul_4k *t;
- int j, k;
-
- t = kzalloc(sizeof(*t), GFP_KERNEL);
- if (!t)
- goto out;
-
- t->t[1] = *g;
- for (j = 1; j <= 64; j <<= 1)
- gf128mul_x_bbe(&t->t[j + j], &t->t[j]);
-
- for (j = 2; j < 256; j += j)
- for (k = 1; k < j; ++k)
- be128_xor(&t->t[j + k], &t->t[j], &t->t[k]);
-
-out:
- return t;
-}
-EXPORT_SYMBOL(gf128mul_init_4k_bbe);
-
-void gf128mul_4k_lle(be128 *a, const struct gf128mul_4k *t)
-{
- u8 *ap = (u8 *)a;
- be128 r[1];
- int i = 15;
-
- *r = t->t[ap[15]];
- while (i--) {
- gf128mul_x8_lle(r);
- be128_xor(r, r, &t->t[ap[i]]);
- }
- *a = *r;
-}
-EXPORT_SYMBOL(gf128mul_4k_lle);
-
-void gf128mul_4k_bbe(be128 *a, const struct gf128mul_4k *t)
-{
- u8 *ap = (u8 *)a;
- be128 r[1];
- int i = 0;
-
- *r = t->t[ap[0]];
- while (++i < 16) {
- gf128mul_x8_bbe(r);
- be128_xor(r, r, &t->t[ap[i]]);
- }
- *a = *r;
-}
-EXPORT_SYMBOL(gf128mul_4k_bbe);
-
-MODULE_LICENSE("GPL");
-MODULE_DESCRIPTION("Functions for multiplying elements of GF(2^128)");
git.samba.org / sfrench / cifs-2.6.git / blobdiff