/src/openssl/crypto/dh/dh_check.c

Source (jump to first uncovered line)
/*
 * Copyright 1995-2017 The OpenSSL Project Authors. All Rights Reserved.
 *
 * Licensed under the OpenSSL license (the "License").  You may not use
 * this file except in compliance with the License.  You can obtain a copy
 * in the file LICENSE in the source distribution or at
 * https://www.openssl.org/source/license.html
 */

#include <stdio.h>
#include "internal/cryptlib.h"
#include <openssl/bn.h>
#include "dh_locl.h"

/*-
 * Check that p and g are suitable enough
 *
 * p is odd
 * 1 < g < p - 1
 */
int DH_check_params_ex(const DH *dh)
{
    int errflags = 0;

    (void)DH_check_params(dh, &errflags);

    if ((errflags & DH_CHECK_P_NOT_PRIME) != 0)
        DHerr(DH_F_DH_CHECK_PARAMS_EX, DH_R_CHECK_P_NOT_PRIME);
    if ((errflags & DH_NOT_SUITABLE_GENERATOR) != 0)
        DHerr(DH_F_DH_CHECK_PARAMS_EX, DH_R_NOT_SUITABLE_GENERATOR);

    return errflags == 0;
}

int DH_check_params(const DH *dh, int *ret)
{
    int ok = 0;
    BIGNUM *tmp = NULL;
    BN_CTX *ctx = NULL;

    *ret = 0;
    ctx = BN_CTX_new();
    if (ctx == NULL)
        goto err;
    BN_CTX_start(ctx);
    tmp = BN_CTX_get(ctx);
    if (tmp == NULL)
        goto err;

    if (!BN_is_odd(dh->p))
        *ret |= DH_CHECK_P_NOT_PRIME;
    if (BN_is_negative(dh->g) || BN_is_zero(dh->g) || BN_is_one(dh->g))
        *ret |= DH_NOT_SUITABLE_GENERATOR;
    if (BN_copy(tmp, dh->p) == NULL || !BN_sub_word(tmp, 1))
        goto err;
    if (BN_cmp(dh->g, tmp) >= 0)
        *ret |= DH_NOT_SUITABLE_GENERATOR;

    ok = 1;
 err:
    if (ctx != NULL) {
        BN_CTX_end(ctx);
        BN_CTX_free(ctx);
    }
    return ok;
}

/*-
 * Check that p is a safe prime and
 * if g is 2, 3 or 5, check that it is a suitable generator
 * where
 * for 2, p mod 24 == 11
 * for 3, p mod 12 == 5
 * for 5, p mod 10 == 3 or 7
 * should hold.
 */
int DH_check_ex(const DH *dh)
{
    int errflags = 0;

    (void)DH_check(dh, &errflags);

    if ((errflags & DH_NOT_SUITABLE_GENERATOR) != 0)
        DHerr(DH_F_DH_CHECK_EX, DH_R_NOT_SUITABLE_GENERATOR);
    if ((errflags & DH_CHECK_Q_NOT_PRIME) != 0)
        DHerr(DH_F_DH_CHECK_EX, DH_R_CHECK_Q_NOT_PRIME);
    if ((errflags & DH_CHECK_INVALID_Q_VALUE) != 0)
        DHerr(DH_F_DH_CHECK_EX, DH_R_CHECK_INVALID_Q_VALUE);
    if ((errflags & DH_CHECK_INVALID_J_VALUE) != 0)
        DHerr(DH_F_DH_CHECK_EX, DH_R_CHECK_INVALID_J_VALUE);
    if ((errflags & DH_UNABLE_TO_CHECK_GENERATOR) != 0)
        DHerr(DH_F_DH_CHECK_EX, DH_R_UNABLE_TO_CHECK_GENERATOR);
    if ((errflags & DH_CHECK_P_NOT_PRIME) != 0)
        DHerr(DH_F_DH_CHECK_EX, DH_R_CHECK_P_NOT_PRIME);
    if ((errflags & DH_CHECK_P_NOT_SAFE_PRIME) != 0)
        DHerr(DH_F_DH_CHECK_EX, DH_R_CHECK_P_NOT_SAFE_PRIME);

    return errflags == 0;
}

int DH_check(const DH *dh, int *ret)
{
    int ok = 0, r;
    BN_CTX *ctx = NULL;
    BN_ULONG l;
    BIGNUM *t1 = NULL, *t2 = NULL;

    *ret = 0;
    ctx = BN_CTX_new();
    if (ctx == NULL)
        goto err;
    BN_CTX_start(ctx);
    t1 = BN_CTX_get(ctx);
    t2 = BN_CTX_get(ctx);
    if (t2 == NULL)
        goto err;

    if (dh->q) {
        if (BN_cmp(dh->g, BN_value_one()) <= 0)
            *ret |= DH_NOT_SUITABLE_GENERATOR;
        else if (BN_cmp(dh->g, dh->p) >= 0)
            *ret |= DH_NOT_SUITABLE_GENERATOR;
        else {
            /* Check g^q == 1 mod p */
            if (!BN_mod_exp(t1, dh->g, dh->q, dh->p, ctx))
                goto err;
            if (!BN_is_one(t1))
                *ret |= DH_NOT_SUITABLE_GENERATOR;
        }
        r = BN_is_prime_ex(dh->q, BN_prime_checks, ctx, NULL);
        if (r < 0)
            goto err;
        if (!r)
            *ret |= DH_CHECK_Q_NOT_PRIME;
        /* Check p == 1 mod q  i.e. q divides p - 1 */
        if (!BN_div(t1, t2, dh->p, dh->q, ctx))
            goto err;
        if (!BN_is_one(t2))
            *ret |= DH_CHECK_INVALID_Q_VALUE;
        if (dh->j && BN_cmp(dh->j, t1))
            *ret |= DH_CHECK_INVALID_J_VALUE;

    } else if (BN_is_word(dh->g, DH_GENERATOR_2)) {
        l = BN_mod_word(dh->p, 24);
        if (l == (BN_ULONG)-1)
            goto err;
        if (l != 11)
            *ret |= DH_NOT_SUITABLE_GENERATOR;
    } else if (BN_is_word(dh->g, DH_GENERATOR_5)) {
        l = BN_mod_word(dh->p, 10);
        if (l == (BN_ULONG)-1)
            goto err;
        if ((l != 3) && (l != 7))
            *ret |= DH_NOT_SUITABLE_GENERATOR;
    } else
        *ret |= DH_UNABLE_TO_CHECK_GENERATOR;

    r = BN_is_prime_ex(dh->p, BN_prime_checks, ctx, NULL);
    if (r < 0)
        goto err;
    if (!r)
        *ret |= DH_CHECK_P_NOT_PRIME;
    else if (!dh->q) {
        if (!BN_rshift1(t1, dh->p))
            goto err;
        r = BN_is_prime_ex(t1, BN_prime_checks, ctx, NULL);
        if (r < 0)
            goto err;
        if (!r)
            *ret |= DH_CHECK_P_NOT_SAFE_PRIME;
    }
    ok = 1;
 err:
    if (ctx != NULL) {
        BN_CTX_end(ctx);
        BN_CTX_free(ctx);
    }
    return ok;
}

int DH_check_pub_key_ex(const DH *dh, const BIGNUM *pub_key)
{
    int errflags = 0;

    (void)DH_check(dh, &errflags);

    if ((errflags & DH_CHECK_PUBKEY_TOO_SMALL) != 0)
        DHerr(DH_F_DH_CHECK_PUB_KEY_EX, DH_R_CHECK_PUBKEY_TOO_SMALL);
    if ((errflags & DH_CHECK_PUBKEY_TOO_LARGE) != 0)
        DHerr(DH_F_DH_CHECK_PUB_KEY_EX, DH_R_CHECK_PUBKEY_TOO_LARGE);
    if ((errflags & DH_CHECK_PUBKEY_INVALID) != 0)
        DHerr(DH_F_DH_CHECK_PUB_KEY_EX, DH_R_CHECK_PUBKEY_INVALID);

    return errflags == 0;
}

int DH_check_pub_key(const DH *dh, const BIGNUM *pub_key, int *ret)
{
    int ok = 0;
    BIGNUM *tmp = NULL;
    BN_CTX *ctx = NULL;

    *ret = 0;
    ctx = BN_CTX_new();
    if (ctx == NULL)
        goto err;
    BN_CTX_start(ctx);
    tmp = BN_CTX_get(ctx);
    if (tmp == NULL || !BN_set_word(tmp, 1))
        goto err;
    if (BN_cmp(pub_key, tmp) <= 0)
        *ret |= DH_CHECK_PUBKEY_TOO_SMALL;
    if (BN_copy(tmp, dh->p) == NULL || !BN_sub_word(tmp, 1))
        goto err;
    if (BN_cmp(pub_key, tmp) >= 0)
        *ret |= DH_CHECK_PUBKEY_TOO_LARGE;

    if (dh->q != NULL) {
        /* Check pub_key^q == 1 mod p */
        if (!BN_mod_exp(tmp, pub_key, dh->q, dh->p, ctx))
            goto err;
        if (!BN_is_one(tmp))
            *ret |= DH_CHECK_PUBKEY_INVALID;
    }

    ok = 1;
 err:
    if (ctx != NULL) {
        BN_CTX_end(ctx);
        BN_CTX_free(ctx);
    }
    return ok;
}

Coverage Report

Created: 2018-08-29 13:53

Line	Count	Source (jump to first uncovered line)
1		/*
2		* Copyright 1995-2017 The OpenSSL Project Authors. All Rights Reserved.
3		*
4		* Licensed under the OpenSSL license (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
8		*/
9
10		#include <stdio.h>
11		#include "internal/cryptlib.h"
12		#include <openssl/bn.h>
13		#include "dh_locl.h"
14
15		/*-
16		* Check that p and g are suitable enough
17		*
18		* p is odd
19		* 1 < g < p - 1
20		*/
21		int DH_check_params_ex(const DH *dh)
22	0	{
23	0	int errflags = 0;
24	0
25	0	(void)DH_check_params(dh, &errflags);
26	0
27	0	if ((errflags & DH_CHECK_P_NOT_PRIME) != 0)
28	0	DHerr(DH_F_DH_CHECK_PARAMS_EX, DH_R_CHECK_P_NOT_PRIME);
29	0	if ((errflags & DH_NOT_SUITABLE_GENERATOR) != 0)
30	0	DHerr(DH_F_DH_CHECK_PARAMS_EX, DH_R_NOT_SUITABLE_GENERATOR);
31	0
32	0	return errflags == 0;
33	0	}
34
35		int DH_check_params(const DH dh, int ret)
36	0	{
37	0	int ok = 0;
38	0	BIGNUM *tmp = NULL;
39	0	BN_CTX *ctx = NULL;
40	0
41	0	*ret = 0;
42	0	ctx = BN_CTX_new();
43	0	if (ctx == NULL)
44	0	goto err;
45	0	BN_CTX_start(ctx);
46	0	tmp = BN_CTX_get(ctx);
47	0	if (tmp == NULL)
48	0	goto err;
49	0
50	0	if (!BN_is_odd(dh->p))
51	0	*ret \|= DH_CHECK_P_NOT_PRIME;
52	0	if (BN_is_negative(dh->g) \|\| BN_is_zero(dh->g) \|\| BN_is_one(dh->g))
53	0	*ret \|= DH_NOT_SUITABLE_GENERATOR;
54	0	if (BN_copy(tmp, dh->p) == NULL \|\| !BN_sub_word(tmp, 1))
55	0	goto err;
56	0	if (BN_cmp(dh->g, tmp) >= 0)
57	0	*ret \|= DH_NOT_SUITABLE_GENERATOR;
58	0
59	0	ok = 1;
60	0	err:
61	0	if (ctx != NULL) {
62	0	BN_CTX_end(ctx);
63	0	BN_CTX_free(ctx);
64	0	}
65	0	return ok;
66	0	}
67
68		/*-
69		* Check that p is a safe prime and
70		* if g is 2, 3 or 5, check that it is a suitable generator
71		* where
72		* for 2, p mod 24 == 11
73		* for 3, p mod 12 == 5
74		* for 5, p mod 10 == 3 or 7
75		* should hold.
76		*/
77		int DH_check_ex(const DH *dh)
78	0	{
79	0	int errflags = 0;
80	0
81	0	(void)DH_check(dh, &errflags);
82	0
83	0	if ((errflags & DH_NOT_SUITABLE_GENERATOR) != 0)
84	0	DHerr(DH_F_DH_CHECK_EX, DH_R_NOT_SUITABLE_GENERATOR);
85	0	if ((errflags & DH_CHECK_Q_NOT_PRIME) != 0)
86	0	DHerr(DH_F_DH_CHECK_EX, DH_R_CHECK_Q_NOT_PRIME);
87	0	if ((errflags & DH_CHECK_INVALID_Q_VALUE) != 0)
88	0	DHerr(DH_F_DH_CHECK_EX, DH_R_CHECK_INVALID_Q_VALUE);
89	0	if ((errflags & DH_CHECK_INVALID_J_VALUE) != 0)
90	0	DHerr(DH_F_DH_CHECK_EX, DH_R_CHECK_INVALID_J_VALUE);
91	0	if ((errflags & DH_UNABLE_TO_CHECK_GENERATOR) != 0)
92	0	DHerr(DH_F_DH_CHECK_EX, DH_R_UNABLE_TO_CHECK_GENERATOR);
93	0	if ((errflags & DH_CHECK_P_NOT_PRIME) != 0)
94	0	DHerr(DH_F_DH_CHECK_EX, DH_R_CHECK_P_NOT_PRIME);
95	0	if ((errflags & DH_CHECK_P_NOT_SAFE_PRIME) != 0)
96	0	DHerr(DH_F_DH_CHECK_EX, DH_R_CHECK_P_NOT_SAFE_PRIME);
97	0
98	0	return errflags == 0;
99	0	}
100
101		int DH_check(const DH dh, int ret)
102	0	{
103	0	int ok = 0, r;
104	0	BN_CTX *ctx = NULL;
105	0	BN_ULONG l;
106	0	BIGNUM t1 = NULL, t2 = NULL;
107	0
108	0	*ret = 0;
109	0	ctx = BN_CTX_new();
110	0	if (ctx == NULL)
111	0	goto err;
112	0	BN_CTX_start(ctx);
113	0	t1 = BN_CTX_get(ctx);
114	0	t2 = BN_CTX_get(ctx);
115	0	if (t2 == NULL)
116	0	goto err;
117	0
118	0	if (dh->q) {
119	0	if (BN_cmp(dh->g, BN_value_one()) <= 0)
120	0	*ret \|= DH_NOT_SUITABLE_GENERATOR;
121	0	else if (BN_cmp(dh->g, dh->p) >= 0)
122	0	*ret \|= DH_NOT_SUITABLE_GENERATOR;
123	0	else {
124	0	/* Check g^q == 1 mod p */
125	0	if (!BN_mod_exp(t1, dh->g, dh->q, dh->p, ctx))
126	0	goto err;
127	0	if (!BN_is_one(t1))
128	0	*ret \|= DH_NOT_SUITABLE_GENERATOR;
129	0	}
130	0	r = BN_is_prime_ex(dh->q, BN_prime_checks, ctx, NULL);
131	0	if (r < 0)
132	0	goto err;
133	0	if (!r)
134	0	*ret \|= DH_CHECK_Q_NOT_PRIME;
135	0	/* Check p == 1 mod q i.e. q divides p - 1 */
136	0	if (!BN_div(t1, t2, dh->p, dh->q, ctx))
137	0	goto err;
138	0	if (!BN_is_one(t2))
139	0	*ret \|= DH_CHECK_INVALID_Q_VALUE;
140	0	if (dh->j && BN_cmp(dh->j, t1))
141	0	*ret \|= DH_CHECK_INVALID_J_VALUE;
142	0
143	0	} else if (BN_is_word(dh->g, DH_GENERATOR_2)) {
144	0	l = BN_mod_word(dh->p, 24);
145	0	if (l == (BN_ULONG)-1)
146	0	goto err;
147	0	if (l != 11)
148	0	*ret \|= DH_NOT_SUITABLE_GENERATOR;
149	0	} else if (BN_is_word(dh->g, DH_GENERATOR_5)) {
150	0	l = BN_mod_word(dh->p, 10);
151	0	if (l == (BN_ULONG)-1)
152	0	goto err;
153	0	if ((l != 3) && (l != 7))
154	0	*ret \|= DH_NOT_SUITABLE_GENERATOR;
155	0	} else
156	0	*ret \|= DH_UNABLE_TO_CHECK_GENERATOR;
157	0
158	0	r = BN_is_prime_ex(dh->p, BN_prime_checks, ctx, NULL);
159	0	if (r < 0)
160	0	goto err;
161	0	if (!r)
162	0	*ret \|= DH_CHECK_P_NOT_PRIME;
163	0	else if (!dh->q) {
164	0	if (!BN_rshift1(t1, dh->p))
165	0	goto err;
166	0	r = BN_is_prime_ex(t1, BN_prime_checks, ctx, NULL);
167	0	if (r < 0)
168	0	goto err;
169	0	if (!r)
170	0	*ret \|= DH_CHECK_P_NOT_SAFE_PRIME;
171	0	}
172	0	ok = 1;
173	0	err:
174	0	if (ctx != NULL) {
175	0	BN_CTX_end(ctx);
176	0	BN_CTX_free(ctx);
177	0	}
178	0	return ok;
179	0	}
180
181		int DH_check_pub_key_ex(const DH dh, const BIGNUM pub_key)
182	0	{
183	0	int errflags = 0;
184	0
185	0	(void)DH_check(dh, &errflags);
186	0
187	0	if ((errflags & DH_CHECK_PUBKEY_TOO_SMALL) != 0)
188	0	DHerr(DH_F_DH_CHECK_PUB_KEY_EX, DH_R_CHECK_PUBKEY_TOO_SMALL);
189	0	if ((errflags & DH_CHECK_PUBKEY_TOO_LARGE) != 0)
190	0	DHerr(DH_F_DH_CHECK_PUB_KEY_EX, DH_R_CHECK_PUBKEY_TOO_LARGE);
191	0	if ((errflags & DH_CHECK_PUBKEY_INVALID) != 0)
192	0	DHerr(DH_F_DH_CHECK_PUB_KEY_EX, DH_R_CHECK_PUBKEY_INVALID);
193	0
194	0	return errflags == 0;
195	0	}
196
197		int DH_check_pub_key(const DH dh, const BIGNUM pub_key, int *ret)
198	0	{
199	0	int ok = 0;
200	0	BIGNUM *tmp = NULL;
201	0	BN_CTX *ctx = NULL;
202	0
203	0	*ret = 0;
204	0	ctx = BN_CTX_new();
205	0	if (ctx == NULL)
206	0	goto err;
207	0	BN_CTX_start(ctx);
208	0	tmp = BN_CTX_get(ctx);
209	0	if (tmp == NULL \|\| !BN_set_word(tmp, 1))
210	0	goto err;
211	0	if (BN_cmp(pub_key, tmp) <= 0)
212	0	*ret \|= DH_CHECK_PUBKEY_TOO_SMALL;
213	0	if (BN_copy(tmp, dh->p) == NULL \|\| !BN_sub_word(tmp, 1))
214	0	goto err;
215	0	if (BN_cmp(pub_key, tmp) >= 0)
216	0	*ret \|= DH_CHECK_PUBKEY_TOO_LARGE;
217	0
218	0	if (dh->q != NULL) {
219	0	/* Check pub_key^q == 1 mod p */
220	0	if (!BN_mod_exp(tmp, pub_key, dh->q, dh->p, ctx))
221	0	goto err;
222	0	if (!BN_is_one(tmp))
223	0	*ret \|= DH_CHECK_PUBKEY_INVALID;
224	0	}
225	0
226	0	ok = 1;
227	0	err:
228	0	if (ctx != NULL) {
229	0	BN_CTX_end(ctx);
230	0	BN_CTX_free(ctx);
231	0	}
232	0	return ok;
233	0	}