src/tls/bignum.c

   1 /*
   2  * Big number math
   3  * Copyright (c) 2006, Jouni Malinen <j@w1.fi>
   4  *
   5  * This program is free software; you can redistribute it and/or modify
   6  * it under the terms of the GNU General Public License version 2 as
   7  * published by the Free Software Foundation.
   8  *
   9  * Alternatively, this software may be distributed under the terms of BSD
  10  * license.
  11  *
  12  * See README and COPYING for more details.
  13  */
  14
  15 #include "includes.h"
  16
  17 #include "common.h"
  18 #include "bignum.h"
  19
  20 #ifdef CONFIG_INTERNAL_LIBTOMMATH
  21 #include "libtommath.c"
  22 #else /* CONFIG_INTERNAL_LIBTOMMATH */
  23 #include <tommath.h>
  24 #endif /* CONFIG_INTERNAL_LIBTOMMATH */
  25
  26
  27 /*
  28  * The current version is just a wrapper for LibTomMath library, so
  29  * struct bignum is just typecast to mp_int.
  30  */
  31
  32 /**
  33  * bignum_init - Allocate memory for bignum
  34  * Returns: Pointer to allocated bignum or %NULL on failure
  35  */
  36 struct bignum * bignum_init(void)
  37 {
  38         struct bignum *n = os_zalloc(sizeof(mp_int));
  39         if (n == NULL)
  40                 return NULL;
  41         if (mp_init((mp_int *) n) != MP_OKAY) {
  42                 os_free(n);
  43                 n = NULL;
  44         }
  45         return n;
  46 }
  47
  48
  49 /**
  50  * bignum_deinit - Free bignum
  51  * @n: Bignum from bignum_init()
  52  */
  53 void bignum_deinit(struct bignum *n)
  54 {
  55         if (n) {
  56                 mp_clear((mp_int *) n);
  57                 os_free(n);
  58         }
  59 }
  60
  61
  62 /**
  63  * bignum_get_unsigned_bin - Get length of bignum as an unsigned binary buffer
  64  * @n: Bignum from bignum_init()
  65  * Returns: Length of n if written to a binary buffer
  66  */
  67 size_t bignum_get_unsigned_bin_len(struct bignum *n)
  68 {
  69         return mp_unsigned_bin_size((mp_int *) n);
  70 }
  71
  72
  73 /**
  74  * bignum_get_unsigned_bin - Set binary buffer to unsigned bignum
  75  * @n: Bignum from bignum_init()
  76  * @buf: Buffer for the binary number
  77  * @len: Length of the buffer, can be %NULL if buffer is known to be long
  78  * enough. Set to used buffer length on success if not %NULL.
  79  * Returns: 0 on success, -1 on failure
  80  */
  81 int bignum_get_unsigned_bin(const struct bignum *n, u8 *buf, size_t *len)
  82 {
  83         size_t need = mp_unsigned_bin_size((mp_int *) n);
  84         if (len && need > *len) {
  85                 *len = need;
  86                 return -1;
  87         }
  88         if (mp_to_unsigned_bin((mp_int *) n, buf) != MP_OKAY) {
  89                 wpa_printf(MSG_DEBUG, "BIGNUM: %s failed", __func__);
  90                 return -1;
  91         }
  92         if (len)
  93                 *len = need;
  94         return 0;
  95 }
  96
  97
  98 /**
  99  * bignum_set_unsigned_bin - Set bignum based on unsigned binary buffer
 100  * @a: Bignum from bignum_init(); to be set to the given value
 101  * @buf: Buffer with unsigned binary value
 102  * @len: Length of buf in octets
 103  * Returns: 0 on success, -1 on failure
 104  */
 105 int bignum_set_unsigned_bin(struct bignum *n, const u8 *buf, size_t len)
 106 {
 107         if (mp_read_unsigned_bin((mp_int *) n, (u8 *) buf, len) != MP_OKAY) {
 108                 wpa_printf(MSG_DEBUG, "BIGNUM: %s failed", __func__);
 109                 return -1;
 110         }
 111         return 0;
 112 }
 113
 114
 115 /**
 116  * bignum_cmp - Signed comparison
 117  * @a: Bignum from bignum_init()
 118  * @b: Bignum from bignum_init()
 119  * Returns: 0 on success, -1 on failure
 120  */
 121 int bignum_cmp(const struct bignum *a, const struct bignum *b)
 122 {
 123         return mp_cmp((mp_int *) a, (mp_int *) b);
 124 }
 125
 126
 127 /**
 128  * bignum_cmd_d - Compare bignum to standard integer
 129  * @a: Bignum from bignum_init()
 130  * @b: Small integer
 131  * Returns: 0 on success, -1 on failure
 132  */
 133 int bignum_cmp_d(const struct bignum *a, unsigned long b)
 134 {
 135         return mp_cmp_d((mp_int *) a, b);
 136 }
 137
 138
 139 /**
 140  * bignum_add - c = a + b
 141  * @a: Bignum from bignum_init()
 142  * @b: Bignum from bignum_init()
 143  * @c: Bignum from bignum_init(); used to store the result of a + b
 144  * Returns: 0 on success, -1 on failure
 145  */
 146 int bignum_add(const struct bignum *a, const struct bignum *b,
 147                struct bignum *c)
 148 {
 149         if (mp_add((mp_int *) a, (mp_int *) b, (mp_int *) c) != MP_OKAY) {
 150                 wpa_printf(MSG_DEBUG, "BIGNUM: %s failed", __func__);
 151                 return -1;
 152         }
 153         return 0;
 154 }
 155
 156
 157 /**
 158  * bignum_sub - c = a - b
 159  * @a: Bignum from bignum_init()
 160  * @b: Bignum from bignum_init()
 161  * @c: Bignum from bignum_init(); used to store the result of a - b
 162  * Returns: 0 on success, -1 on failure
 163  */
 164 int bignum_sub(const struct bignum *a, const struct bignum *b,
 165                struct bignum *c)
 166 {
 167         if (mp_sub((mp_int *) a, (mp_int *) b, (mp_int *) c) != MP_OKAY) {
 168                 wpa_printf(MSG_DEBUG, "BIGNUM: %s failed", __func__);
 169                 return -1;
 170         }
 171         return 0;
 172 }
 173
 174
 175 /**
 176  * bignum_mul - c = a * b
 177  * @a: Bignum from bignum_init()
 178  * @b: Bignum from bignum_init()
 179  * @c: Bignum from bignum_init(); used to store the result of a * b
 180  * Returns: 0 on success, -1 on failure
 181  */
 182 int bignum_mul(const struct bignum *a, const struct bignum *b,
 183                struct bignum *c)
 184 {
 185         if (mp_mul((mp_int *) a, (mp_int *) b, (mp_int *) c) != MP_OKAY) {
 186                 wpa_printf(MSG_DEBUG, "BIGNUM: %s failed", __func__);
 187                 return -1;
 188         }
 189         return 0;
 190 }
 191
 192
 193 /**
 194  * bignum_mulmod - d = a * b (mod c)
 195  * @a: Bignum from bignum_init()
 196  * @b: Bignum from bignum_init()
 197  * @c: Bignum from bignum_init(); modulus
 198  * @d: Bignum from bignum_init(); used to store the result of a * b (mod c)
 199  * Returns: 0 on success, -1 on failure
 200  */
 201 int bignum_mulmod(const struct bignum *a, const struct bignum *b,
 202                   const struct bignum *c, struct bignum *d)
 203 {
 204         if (mp_mulmod((mp_int *) a, (mp_int *) b, (mp_int *) c, (mp_int *) d)
 205             != MP_OKAY) {
 206                 wpa_printf(MSG_DEBUG, "BIGNUM: %s failed", __func__);
 207                 return -1;
 208         }
 209         return 0;
 210 }
 211
 212
 213 /**
 214  * bignum_exptmod - Modular exponentiation: d = a^b (mod c)
 215  * @a: Bignum from bignum_init(); base
 216  * @b: Bignum from bignum_init(); exponent
 217  * @c: Bignum from bignum_init(); modulus
 218  * @d: Bignum from bignum_init(); used to store the result of a^b (mod c)
 219  * Returns: 0 on success, -1 on failure
 220  */
 221 int bignum_exptmod(const struct bignum *a, const struct bignum *b,
 222                    const struct bignum *c, struct bignum *d)
 223 {
 224         if (mp_exptmod((mp_int *) a, (mp_int *) b, (mp_int *) c, (mp_int *) d)
 225             != MP_OKAY) {
 226                 wpa_printf(MSG_DEBUG, "BIGNUM: %s failed", __func__);
 227                 return -1;
 228         }
 229         return 0;
 230 }