2 * Copyright 1995-2019 The OpenSSL Project Authors. All Rights Reserved.
4 * Licensed under the Apache License 2.0 (the "License"). You may not use
5 * this file except in compliance with the License. You can obtain a copy
6 * in the file LICENSE in the source distribution or at
7 * https://www.openssl.org/source/license.html
11 #include "internal/cryptlib.h"
12 #include <openssl/bn.h>
16 * Check that p and g are suitable enough
21 int DH_check_params_ex(const DH
*dh
)
25 if (!DH_check_params(dh
, &errflags
))
28 if ((errflags
& DH_CHECK_P_NOT_PRIME
) != 0)
29 DHerr(DH_F_DH_CHECK_PARAMS_EX
, DH_R_CHECK_P_NOT_PRIME
);
30 if ((errflags
& DH_NOT_SUITABLE_GENERATOR
) != 0)
31 DHerr(DH_F_DH_CHECK_PARAMS_EX
, DH_R_NOT_SUITABLE_GENERATOR
);
32 if ((errflags
& DH_MODULUS_TOO_SMALL
) != 0)
33 DHerr(DH_F_DH_CHECK_PARAMS_EX
, DH_R_MODULUS_TOO_SMALL
);
34 if ((errflags
& DH_MODULUS_TOO_LARGE
) != 0)
35 DHerr(DH_F_DH_CHECK_PARAMS_EX
, DH_R_MODULUS_TOO_LARGE
);
40 int DH_check_params(const DH
*dh
, int *ret
)
51 tmp
= BN_CTX_get(ctx
);
55 if (!BN_is_odd(dh
->p
))
56 *ret
|= DH_CHECK_P_NOT_PRIME
;
57 if (BN_is_negative(dh
->g
) || BN_is_zero(dh
->g
) || BN_is_one(dh
->g
))
58 *ret
|= DH_NOT_SUITABLE_GENERATOR
;
59 if (BN_copy(tmp
, dh
->p
) == NULL
|| !BN_sub_word(tmp
, 1))
61 if (BN_cmp(dh
->g
, tmp
) >= 0)
62 *ret
|= DH_NOT_SUITABLE_GENERATOR
;
63 if (BN_num_bits(dh
->p
) < DH_MIN_MODULUS_BITS
)
64 *ret
|= DH_MODULUS_TOO_SMALL
;
65 if (BN_num_bits(dh
->p
) > OPENSSL_DH_MAX_MODULUS_BITS
)
66 *ret
|= DH_MODULUS_TOO_LARGE
;
76 * Check that p is a safe prime and
77 * g is a suitable generator.
79 int DH_check_ex(const DH
*dh
)
83 if (!DH_check(dh
, &errflags
))
86 if ((errflags
& DH_NOT_SUITABLE_GENERATOR
) != 0)
87 DHerr(DH_F_DH_CHECK_EX
, DH_R_NOT_SUITABLE_GENERATOR
);
88 if ((errflags
& DH_CHECK_Q_NOT_PRIME
) != 0)
89 DHerr(DH_F_DH_CHECK_EX
, DH_R_CHECK_Q_NOT_PRIME
);
90 if ((errflags
& DH_CHECK_INVALID_Q_VALUE
) != 0)
91 DHerr(DH_F_DH_CHECK_EX
, DH_R_CHECK_INVALID_Q_VALUE
);
92 if ((errflags
& DH_CHECK_INVALID_J_VALUE
) != 0)
93 DHerr(DH_F_DH_CHECK_EX
, DH_R_CHECK_INVALID_J_VALUE
);
94 if ((errflags
& DH_UNABLE_TO_CHECK_GENERATOR
) != 0)
95 DHerr(DH_F_DH_CHECK_EX
, DH_R_UNABLE_TO_CHECK_GENERATOR
);
96 if ((errflags
& DH_CHECK_P_NOT_PRIME
) != 0)
97 DHerr(DH_F_DH_CHECK_EX
, DH_R_CHECK_P_NOT_PRIME
);
98 if ((errflags
& DH_CHECK_P_NOT_SAFE_PRIME
) != 0)
99 DHerr(DH_F_DH_CHECK_EX
, DH_R_CHECK_P_NOT_SAFE_PRIME
);
100 if ((errflags
& DH_MODULUS_TOO_SMALL
) != 0)
101 DHerr(DH_F_DH_CHECK_EX
, DH_R_MODULUS_TOO_SMALL
);
102 if ((errflags
& DH_MODULUS_TOO_LARGE
) != 0)
103 DHerr(DH_F_DH_CHECK_EX
, DH_R_MODULUS_TOO_LARGE
);
105 return errflags
== 0;
108 int DH_check(const DH
*dh
, int *ret
)
112 BIGNUM
*t1
= NULL
, *t2
= NULL
;
114 if (!DH_check_params(dh
, ret
))
121 t1
= BN_CTX_get(ctx
);
122 t2
= BN_CTX_get(ctx
);
127 if (BN_cmp(dh
->g
, BN_value_one()) <= 0)
128 *ret
|= DH_NOT_SUITABLE_GENERATOR
;
129 else if (BN_cmp(dh
->g
, dh
->p
) >= 0)
130 *ret
|= DH_NOT_SUITABLE_GENERATOR
;
132 /* Check g^q == 1 mod p */
133 if (!BN_mod_exp(t1
, dh
->g
, dh
->q
, dh
->p
, ctx
))
136 *ret
|= DH_NOT_SUITABLE_GENERATOR
;
138 r
= BN_check_prime(dh
->q
, ctx
, NULL
);
142 *ret
|= DH_CHECK_Q_NOT_PRIME
;
143 /* Check p == 1 mod q i.e. q divides p - 1 */
144 if (!BN_div(t1
, t2
, dh
->p
, dh
->q
, ctx
))
147 *ret
|= DH_CHECK_INVALID_Q_VALUE
;
148 if (dh
->j
&& BN_cmp(dh
->j
, t1
))
149 *ret
|= DH_CHECK_INVALID_J_VALUE
;
152 r
= BN_check_prime(dh
->p
, ctx
, NULL
);
156 *ret
|= DH_CHECK_P_NOT_PRIME
;
158 if (!BN_rshift1(t1
, dh
->p
))
160 r
= BN_check_prime(t1
, ctx
, NULL
);
164 *ret
|= DH_CHECK_P_NOT_SAFE_PRIME
;
173 int DH_check_pub_key_ex(const DH
*dh
, const BIGNUM
*pub_key
)
177 if (!DH_check_pub_key(dh
, pub_key
, &errflags
))
180 if ((errflags
& DH_CHECK_PUBKEY_TOO_SMALL
) != 0)
181 DHerr(DH_F_DH_CHECK_PUB_KEY_EX
, DH_R_CHECK_PUBKEY_TOO_SMALL
);
182 if ((errflags
& DH_CHECK_PUBKEY_TOO_LARGE
) != 0)
183 DHerr(DH_F_DH_CHECK_PUB_KEY_EX
, DH_R_CHECK_PUBKEY_TOO_LARGE
);
184 if ((errflags
& DH_CHECK_PUBKEY_INVALID
) != 0)
185 DHerr(DH_F_DH_CHECK_PUB_KEY_EX
, DH_R_CHECK_PUBKEY_INVALID
);
187 return errflags
== 0;
190 int DH_check_pub_key(const DH
*dh
, const BIGNUM
*pub_key
, int *ret
)
201 tmp
= BN_CTX_get(ctx
);
202 if (tmp
== NULL
|| !BN_set_word(tmp
, 1))
204 if (BN_cmp(pub_key
, tmp
) <= 0)
205 *ret
|= DH_CHECK_PUBKEY_TOO_SMALL
;
206 if (BN_copy(tmp
, dh
->p
) == NULL
|| !BN_sub_word(tmp
, 1))
208 if (BN_cmp(pub_key
, tmp
) >= 0)
209 *ret
|= DH_CHECK_PUBKEY_TOO_LARGE
;
212 /* Check pub_key^q == 1 mod p */
213 if (!BN_mod_exp(tmp
, pub_key
, dh
->q
, dh
->p
, ctx
))
216 *ret
|= DH_CHECK_PUBKEY_INVALID
;