/src/openssl35/crypto/srp/srp_lib.c

Source
/*
 * Copyright 2004-2021 The OpenSSL Project Authors. All Rights Reserved.
 * Copyright (c) 2004, EdelKey Project. All Rights Reserved.
 *
 * Licensed under the Apache License 2.0 (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
 *
 * Originally written by Christophe Renou and Peter Sylvester,
 * for the EdelKey project.
 */

/* All the SRP APIs in this file are deprecated */
#define OPENSSL_SUPPRESS_DEPRECATED

#ifndef OPENSSL_NO_SRP
#include "internal/cryptlib.h"
#include <openssl/sha.h>
#include <openssl/srp.h>
#include <openssl/evp.h>
#include "crypto/bn_srp.h"

/* calculate = SHA1(PAD(x) || PAD(y)) */

static BIGNUM *srp_Calc_xy(const BIGNUM *x, const BIGNUM *y, const BIGNUM *N,
    OSSL_LIB_CTX *libctx, const char *propq)
{
    unsigned char digest[SHA_DIGEST_LENGTH];
    unsigned char *tmp = NULL;
    int numN = BN_num_bytes(N);
    BIGNUM *res = NULL;
    EVP_MD *sha1 = EVP_MD_fetch(libctx, "SHA1", propq);

    if (sha1 == NULL)
        return NULL;

    if (x != N && BN_ucmp(x, N) >= 0)
        goto err;
    if (y != N && BN_ucmp(y, N) >= 0)
        goto err;
    if ((tmp = OPENSSL_malloc(numN * 2)) == NULL)
        goto err;
    if (BN_bn2binpad(x, tmp, numN) < 0
        || BN_bn2binpad(y, tmp + numN, numN) < 0
        || !EVP_Digest(tmp, numN * 2, digest, NULL, sha1, NULL))
        goto err;
    res = BN_bin2bn(digest, sizeof(digest), NULL);
err:
    EVP_MD_free(sha1);
    OPENSSL_free(tmp);
    return res;
}

static BIGNUM *srp_Calc_k(const BIGNUM *N, const BIGNUM *g,
    OSSL_LIB_CTX *libctx,
    const char *propq)
{
    /* k = SHA1(N | PAD(g)) -- tls-srp RFC 5054 */
    return srp_Calc_xy(N, g, N, libctx, propq);
}

BIGNUM *SRP_Calc_u_ex(const BIGNUM *A, const BIGNUM *B, const BIGNUM *N,
    OSSL_LIB_CTX *libctx, const char *propq)
{
    /* u = SHA1(PAD(A) || PAD(B) ) -- tls-srp RFC 5054 */
    return srp_Calc_xy(A, B, N, libctx, propq);
}

BIGNUM *SRP_Calc_u(const BIGNUM *A, const BIGNUM *B, const BIGNUM *N)
{
    /* u = SHA1(PAD(A) || PAD(B) ) -- tls-srp RFC 5054 */
    return srp_Calc_xy(A, B, N, NULL, NULL);
}

BIGNUM *SRP_Calc_server_key(const BIGNUM *A, const BIGNUM *v, const BIGNUM *u,
    const BIGNUM *b, const BIGNUM *N)
{
    BIGNUM *tmp = NULL, *S = NULL;
    BN_CTX *bn_ctx;

    if (u == NULL || A == NULL || v == NULL || b == NULL || N == NULL)
        return NULL;

    if ((bn_ctx = BN_CTX_new()) == NULL || (tmp = BN_new()) == NULL)
        goto err;

    /* S = (A*v**u) ** b */

    if (!BN_mod_exp(tmp, v, u, N, bn_ctx))
        goto err;
    if (!BN_mod_mul(tmp, A, tmp, N, bn_ctx))
        goto err;

    S = BN_new();
    if (S != NULL && !BN_mod_exp(S, tmp, b, N, bn_ctx)) {
        BN_free(S);
        S = NULL;
    }
err:
    BN_CTX_free(bn_ctx);
    BN_clear_free(tmp);
    return S;
}

BIGNUM *SRP_Calc_B_ex(const BIGNUM *b, const BIGNUM *N, const BIGNUM *g,
    const BIGNUM *v, OSSL_LIB_CTX *libctx, const char *propq)
{
    BIGNUM *kv = NULL, *gb = NULL;
    BIGNUM *B = NULL, *k = NULL;
    BN_CTX *bn_ctx;

    if (b == NULL || N == NULL || g == NULL || v == NULL || (bn_ctx = BN_CTX_new_ex(libctx)) == NULL)
        return NULL;

    if ((kv = BN_new()) == NULL || (gb = BN_new()) == NULL || (B = BN_new()) == NULL)
        goto err;

    /* B = g**b + k*v */

    if (!BN_mod_exp(gb, g, b, N, bn_ctx)
        || (k = srp_Calc_k(N, g, libctx, propq)) == NULL
        || !BN_mod_mul(kv, v, k, N, bn_ctx)
        || !BN_mod_add(B, gb, kv, N, bn_ctx)) {
        BN_free(B);
        B = NULL;
    }
err:
    BN_CTX_free(bn_ctx);
    BN_clear_free(kv);
    BN_clear_free(gb);
    BN_free(k);
    return B;
}

BIGNUM *SRP_Calc_B(const BIGNUM *b, const BIGNUM *N, const BIGNUM *g,
    const BIGNUM *v)
{
    return SRP_Calc_B_ex(b, N, g, v, NULL, NULL);
}

BIGNUM *SRP_Calc_x_ex(const BIGNUM *s, const char *user, const char *pass,
    OSSL_LIB_CTX *libctx, const char *propq)
{
    unsigned char dig[SHA_DIGEST_LENGTH];
    EVP_MD_CTX *ctxt;
    unsigned char *cs = NULL;
    BIGNUM *res = NULL;
    EVP_MD *sha1 = NULL;

    if ((s == NULL) || (user == NULL) || (pass == NULL))
        return NULL;

    ctxt = EVP_MD_CTX_new();
    if (ctxt == NULL)
        return NULL;
    if ((cs = OPENSSL_malloc(BN_num_bytes(s))) == NULL)
        goto err;

    sha1 = EVP_MD_fetch(libctx, "SHA1", propq);
    if (sha1 == NULL)
        goto err;

    if (!EVP_DigestInit_ex(ctxt, sha1, NULL)
        || !EVP_DigestUpdate(ctxt, user, strlen(user))
        || !EVP_DigestUpdate(ctxt, ":", 1)
        || !EVP_DigestUpdate(ctxt, pass, strlen(pass))
        || !EVP_DigestFinal_ex(ctxt, dig, NULL)
        || !EVP_DigestInit_ex(ctxt, sha1, NULL))
        goto err;
    if (BN_bn2bin(s, cs) < 0)
        goto err;
    if (!EVP_DigestUpdate(ctxt, cs, BN_num_bytes(s)))
        goto err;

    if (!EVP_DigestUpdate(ctxt, dig, sizeof(dig))
        || !EVP_DigestFinal_ex(ctxt, dig, NULL))
        goto err;

    res = BN_bin2bn(dig, sizeof(dig), NULL);

err:
    EVP_MD_free(sha1);
    OPENSSL_free(cs);
    EVP_MD_CTX_free(ctxt);
    return res;
}

BIGNUM *SRP_Calc_x(const BIGNUM *s, const char *user, const char *pass)
{
    return SRP_Calc_x_ex(s, user, pass, NULL, NULL);
}

BIGNUM *SRP_Calc_A(const BIGNUM *a, const BIGNUM *N, const BIGNUM *g)
{
    BN_CTX *bn_ctx;
    BIGNUM *A = NULL;

    if (a == NULL || N == NULL || g == NULL || (bn_ctx = BN_CTX_new()) == NULL)
        return NULL;

    if ((A = BN_new()) != NULL && !BN_mod_exp(A, g, a, N, bn_ctx)) {
        BN_free(A);
        A = NULL;
    }
    BN_CTX_free(bn_ctx);
    return A;
}

BIGNUM *SRP_Calc_client_key_ex(const BIGNUM *N, const BIGNUM *B, const BIGNUM *g,
    const BIGNUM *x, const BIGNUM *a, const BIGNUM *u,
    OSSL_LIB_CTX *libctx, const char *propq)
{
    BIGNUM *tmp = NULL, *tmp2 = NULL, *tmp3 = NULL, *k = NULL, *K = NULL;
    BIGNUM *xtmp = NULL;
    BN_CTX *bn_ctx;

    if (u == NULL || B == NULL || N == NULL || g == NULL || x == NULL
        || a == NULL || (bn_ctx = BN_CTX_new_ex(libctx)) == NULL)
        return NULL;

    if ((tmp = BN_new()) == NULL || (tmp2 = BN_new()) == NULL || (tmp3 = BN_new()) == NULL || (xtmp = BN_new()) == NULL)
        goto err;

    BN_with_flags(xtmp, x, BN_FLG_CONSTTIME);
    BN_set_flags(tmp, BN_FLG_CONSTTIME);
    if (!BN_mod_exp(tmp, g, xtmp, N, bn_ctx))
        goto err;
    if ((k = srp_Calc_k(N, g, libctx, propq)) == NULL)
        goto err;
    if (!BN_mod_mul(tmp2, tmp, k, N, bn_ctx))
        goto err;
    if (!BN_mod_sub(tmp, B, tmp2, N, bn_ctx))
        goto err;
    if (!BN_mul(tmp3, u, xtmp, bn_ctx))
        goto err;
    if (!BN_add(tmp2, a, tmp3))
        goto err;
    K = BN_new();
    if (K != NULL && !BN_mod_exp(K, tmp, tmp2, N, bn_ctx)) {
        BN_free(K);
        K = NULL;
    }

err:
    BN_CTX_free(bn_ctx);
    BN_free(xtmp);
    BN_clear_free(tmp);
    BN_clear_free(tmp2);
    BN_clear_free(tmp3);
    BN_free(k);
    return K;
}

BIGNUM *SRP_Calc_client_key(const BIGNUM *N, const BIGNUM *B, const BIGNUM *g,
    const BIGNUM *x, const BIGNUM *a, const BIGNUM *u)
{
    return SRP_Calc_client_key_ex(N, B, g, x, a, u, NULL, NULL);
}

int SRP_Verify_B_mod_N(const BIGNUM *B, const BIGNUM *N)
{
    BIGNUM *r;
    BN_CTX *bn_ctx;
    int ret = 0;

    if (B == NULL || N == NULL || (bn_ctx = BN_CTX_new()) == NULL)
        return 0;

    if ((r = BN_new()) == NULL)
        goto err;
    /* Checks if B % N == 0 */
    if (!BN_nnmod(r, B, N, bn_ctx))
        goto err;
    ret = !BN_is_zero(r);
err:
    BN_CTX_free(bn_ctx);
    BN_free(r);
    return ret;
}

int SRP_Verify_A_mod_N(const BIGNUM *A, const BIGNUM *N)
{
    /* Checks if A % N == 0 */
    return SRP_Verify_B_mod_N(A, N);
}

static SRP_gN knowngN[] = {
    { "8192", &ossl_bn_generator_19, &ossl_bn_group_8192 },
    { "6144", &ossl_bn_generator_5, &ossl_bn_group_6144 },
    { "4096", &ossl_bn_generator_5, &ossl_bn_group_4096 },
    { "3072", &ossl_bn_generator_5, &ossl_bn_group_3072 },
    { "2048", &ossl_bn_generator_2, &ossl_bn_group_2048 },
    { "1536", &ossl_bn_generator_2, &ossl_bn_group_1536 },
    { "1024", &ossl_bn_generator_2, &ossl_bn_group_1024 },
};

#define KNOWN_GN_NUMBER sizeof(knowngN) / sizeof(SRP_gN)

/*
 * Check if G and N are known parameters. The values have been generated
 * from the IETF RFC 5054
 */
char *SRP_check_known_gN_param(const BIGNUM *g, const BIGNUM *N)
{
    size_t i;
    if ((g == NULL) || (N == NULL))
        return NULL;

    for (i = 0; i < KNOWN_GN_NUMBER; i++) {
        if (BN_cmp(knowngN[i].g, g) == 0 && BN_cmp(knowngN[i].N, N) == 0)
            return knowngN[i].id;
    }
    return NULL;
}

SRP_gN *SRP_get_default_gN(const char *id)
{
    size_t i;

    if (id == NULL)
        return knowngN;
    for (i = 0; i < KNOWN_GN_NUMBER; i++) {
        if (strcmp(knowngN[i].id, id) == 0)
            return knowngN + i;
    }
    return NULL;
}
#endif

Coverage Report

Created: 2025-12-31 06:58

Line	Count	Source
1		/*
2		* Copyright 2004-2021 The OpenSSL Project Authors. All Rights Reserved.
3		* Copyright (c) 2004, EdelKey Project. All Rights Reserved.
4		*
5		* Licensed under the Apache License 2.0 (the "License"). You may not use
6		* this file except in compliance with the License. You can obtain a copy
7		* in the file LICENSE in the source distribution or at
8		* https://www.openssl.org/source/license.html
9		*
10		* Originally written by Christophe Renou and Peter Sylvester,
11		* for the EdelKey project.
12		*/
13
14		/* All the SRP APIs in this file are deprecated */
15		#define OPENSSL_SUPPRESS_DEPRECATED
16
17		#ifndef OPENSSL_NO_SRP
18		#include "internal/cryptlib.h"
19		#include <openssl/sha.h>
20		#include <openssl/srp.h>
21		#include <openssl/evp.h>
22		#include "crypto/bn_srp.h"
23
24		/* calculate = SHA1(PAD(x) \|\| PAD(y)) */
25
26		static BIGNUM srp_Calc_xy(const BIGNUM x, const BIGNUM y, const BIGNUM N,
27		OSSL_LIB_CTX libctx, const char propq)
28	0	{
29	0	unsigned char digest[SHA_DIGEST_LENGTH];
30	0	unsigned char *tmp = NULL;
31	0	int numN = BN_num_bytes(N);
32	0	BIGNUM *res = NULL;
33	0	EVP_MD *sha1 = EVP_MD_fetch(libctx, "SHA1", propq);
34
35	0	if (sha1 == NULL)
36	0	return NULL;
37
38	0	if (x != N && BN_ucmp(x, N) >= 0)
39	0	goto err;
40	0	if (y != N && BN_ucmp(y, N) >= 0)
41	0	goto err;
42	0	if ((tmp = OPENSSL_malloc(numN * 2)) == NULL)
43	0	goto err;
44	0	if (BN_bn2binpad(x, tmp, numN) < 0
45	0	\|\| BN_bn2binpad(y, tmp + numN, numN) < 0
46	0	\|\| !EVP_Digest(tmp, numN * 2, digest, NULL, sha1, NULL))
47	0	goto err;
48	0	res = BN_bin2bn(digest, sizeof(digest), NULL);
49	0	err:
50	0	EVP_MD_free(sha1);
51	0	OPENSSL_free(tmp);
52	0	return res;
53	0	}
54
55		static BIGNUM srp_Calc_k(const BIGNUM N, const BIGNUM *g,
56		OSSL_LIB_CTX *libctx,
57		const char *propq)
58	0	{
59		/* k = SHA1(N \| PAD(g)) -- tls-srp RFC 5054 */
60	0	return srp_Calc_xy(N, g, N, libctx, propq);
61	0	}
62
63		BIGNUM SRP_Calc_u_ex(const BIGNUM A, const BIGNUM B, const BIGNUM N,
64		OSSL_LIB_CTX libctx, const char propq)
65	0	{
66		/* u = SHA1(PAD(A) \|\| PAD(B) ) -- tls-srp RFC 5054 */
67	0	return srp_Calc_xy(A, B, N, libctx, propq);
68	0	}
69
70		BIGNUM SRP_Calc_u(const BIGNUM A, const BIGNUM B, const BIGNUM N)
71	0	{
72		/* u = SHA1(PAD(A) \|\| PAD(B) ) -- tls-srp RFC 5054 */
73	0	return srp_Calc_xy(A, B, N, NULL, NULL);
74	0	}
75
76		BIGNUM SRP_Calc_server_key(const BIGNUM A, const BIGNUM v, const BIGNUM u,
77		const BIGNUM b, const BIGNUM N)
78	0	{
79	0	BIGNUM tmp = NULL, S = NULL;
80	0	BN_CTX *bn_ctx;
81
82	0	if (u == NULL \|\| A == NULL \|\| v == NULL \|\| b == NULL \|\| N == NULL)
83	0	return NULL;
84
85	0	if ((bn_ctx = BN_CTX_new()) == NULL \|\| (tmp = BN_new()) == NULL)
86	0	goto err;
87
88		/* S = (Avu) * b */
89
90	0	if (!BN_mod_exp(tmp, v, u, N, bn_ctx))
91	0	goto err;
92	0	if (!BN_mod_mul(tmp, A, tmp, N, bn_ctx))
93	0	goto err;
94
95	0	S = BN_new();
96	0	if (S != NULL && !BN_mod_exp(S, tmp, b, N, bn_ctx)) {
97	0	BN_free(S);
98	0	S = NULL;
99	0	}
100	0	err:
101	0	BN_CTX_free(bn_ctx);
102	0	BN_clear_free(tmp);
103	0	return S;
104	0	}
105
106		BIGNUM SRP_Calc_B_ex(const BIGNUM b, const BIGNUM N, const BIGNUM g,
107		const BIGNUM v, OSSL_LIB_CTX libctx, const char *propq)
108	0	{
109	0	BIGNUM kv = NULL, gb = NULL;
110	0	BIGNUM B = NULL, k = NULL;
111	0	BN_CTX *bn_ctx;
112
113	0	if (b == NULL \|\| N == NULL \|\| g == NULL \|\| v == NULL \|\| (bn_ctx = BN_CTX_new_ex(libctx)) == NULL)
114	0	return NULL;
115
116	0	if ((kv = BN_new()) == NULL \|\| (gb = BN_new()) == NULL \|\| (B = BN_new()) == NULL)
117	0	goto err;
118
119		/* B = g*b + kv */
120
121	0	if (!BN_mod_exp(gb, g, b, N, bn_ctx)
122	0	\|\| (k = srp_Calc_k(N, g, libctx, propq)) == NULL
123	0	\|\| !BN_mod_mul(kv, v, k, N, bn_ctx)
124	0	\|\| !BN_mod_add(B, gb, kv, N, bn_ctx)) {
125	0	BN_free(B);
126	0	B = NULL;
127	0	}
128	0	err:
129	0	BN_CTX_free(bn_ctx);
130	0	BN_clear_free(kv);
131	0	BN_clear_free(gb);
132	0	BN_free(k);
133	0	return B;
134	0	}
135
136		BIGNUM SRP_Calc_B(const BIGNUM b, const BIGNUM N, const BIGNUM g,
137		const BIGNUM *v)
138	0	{
139	0	return SRP_Calc_B_ex(b, N, g, v, NULL, NULL);
140	0	}
141
142		BIGNUM SRP_Calc_x_ex(const BIGNUM s, const char user, const char pass,
143		OSSL_LIB_CTX libctx, const char propq)
144	0	{
145	0	unsigned char dig[SHA_DIGEST_LENGTH];
146	0	EVP_MD_CTX *ctxt;
147	0	unsigned char *cs = NULL;
148	0	BIGNUM *res = NULL;
149	0	EVP_MD *sha1 = NULL;
150
151	0	if ((s == NULL) \|\| (user == NULL) \|\| (pass == NULL))
152	0	return NULL;
153
154	0	ctxt = EVP_MD_CTX_new();
155	0	if (ctxt == NULL)
156	0	return NULL;
157	0	if ((cs = OPENSSL_malloc(BN_num_bytes(s))) == NULL)
158	0	goto err;
159
160	0	sha1 = EVP_MD_fetch(libctx, "SHA1", propq);
161	0	if (sha1 == NULL)
162	0	goto err;
163
164	0	if (!EVP_DigestInit_ex(ctxt, sha1, NULL)
165	0	\|\| !EVP_DigestUpdate(ctxt, user, strlen(user))
166	0	\|\| !EVP_DigestUpdate(ctxt, ":", 1)
167	0	\|\| !EVP_DigestUpdate(ctxt, pass, strlen(pass))
168	0	\|\| !EVP_DigestFinal_ex(ctxt, dig, NULL)
169	0	\|\| !EVP_DigestInit_ex(ctxt, sha1, NULL))
170	0	goto err;
171	0	if (BN_bn2bin(s, cs) < 0)
172	0	goto err;
173	0	if (!EVP_DigestUpdate(ctxt, cs, BN_num_bytes(s)))
174	0	goto err;
175
176	0	if (!EVP_DigestUpdate(ctxt, dig, sizeof(dig))
177	0	\|\| !EVP_DigestFinal_ex(ctxt, dig, NULL))
178	0	goto err;
179
180	0	res = BN_bin2bn(dig, sizeof(dig), NULL);
181
182	0	err:
183	0	EVP_MD_free(sha1);
184	0	OPENSSL_free(cs);
185	0	EVP_MD_CTX_free(ctxt);
186	0	return res;
187	0	}
188
189		BIGNUM SRP_Calc_x(const BIGNUM s, const char user, const char pass)
190	0	{
191	0	return SRP_Calc_x_ex(s, user, pass, NULL, NULL);
192	0	}
193
194		BIGNUM SRP_Calc_A(const BIGNUM a, const BIGNUM N, const BIGNUM g)
195	0	{
196	0	BN_CTX *bn_ctx;
197	0	BIGNUM *A = NULL;
198
199	0	if (a == NULL \|\| N == NULL \|\| g == NULL \|\| (bn_ctx = BN_CTX_new()) == NULL)
200	0	return NULL;
201
202	0	if ((A = BN_new()) != NULL && !BN_mod_exp(A, g, a, N, bn_ctx)) {
203	0	BN_free(A);
204	0	A = NULL;
205	0	}
206	0	BN_CTX_free(bn_ctx);
207	0	return A;
208	0	}
209
210		BIGNUM SRP_Calc_client_key_ex(const BIGNUM N, const BIGNUM B, const BIGNUM g,
211		const BIGNUM x, const BIGNUM a, const BIGNUM *u,
212		OSSL_LIB_CTX libctx, const char propq)
213	0	{
214	0	BIGNUM tmp = NULL, tmp2 = NULL, tmp3 = NULL, k = NULL, *K = NULL;
215	0	BIGNUM *xtmp = NULL;
216	0	BN_CTX *bn_ctx;
217
218	0	if (u == NULL \|\| B == NULL \|\| N == NULL \|\| g == NULL \|\| x == NULL
219	0	\|\| a == NULL \|\| (bn_ctx = BN_CTX_new_ex(libctx)) == NULL)
220	0	return NULL;
221
222	0	if ((tmp = BN_new()) == NULL \|\| (tmp2 = BN_new()) == NULL \|\| (tmp3 = BN_new()) == NULL \|\| (xtmp = BN_new()) == NULL)
223	0	goto err;
224
225	0	BN_with_flags(xtmp, x, BN_FLG_CONSTTIME);
226	0	BN_set_flags(tmp, BN_FLG_CONSTTIME);
227	0	if (!BN_mod_exp(tmp, g, xtmp, N, bn_ctx))
228	0	goto err;
229	0	if ((k = srp_Calc_k(N, g, libctx, propq)) == NULL)
230	0	goto err;
231	0	if (!BN_mod_mul(tmp2, tmp, k, N, bn_ctx))
232	0	goto err;
233	0	if (!BN_mod_sub(tmp, B, tmp2, N, bn_ctx))
234	0	goto err;
235	0	if (!BN_mul(tmp3, u, xtmp, bn_ctx))
236	0	goto err;
237	0	if (!BN_add(tmp2, a, tmp3))
238	0	goto err;
239	0	K = BN_new();
240	0	if (K != NULL && !BN_mod_exp(K, tmp, tmp2, N, bn_ctx)) {
241	0	BN_free(K);
242	0	K = NULL;
243	0	}
244
245	0	err:
246	0	BN_CTX_free(bn_ctx);
247	0	BN_free(xtmp);
248	0	BN_clear_free(tmp);
249	0	BN_clear_free(tmp2);
250	0	BN_clear_free(tmp3);
251	0	BN_free(k);
252	0	return K;
253	0	}
254
255		BIGNUM SRP_Calc_client_key(const BIGNUM N, const BIGNUM B, const BIGNUM g,
256		const BIGNUM x, const BIGNUM a, const BIGNUM *u)
257	0	{
258	0	return SRP_Calc_client_key_ex(N, B, g, x, a, u, NULL, NULL);
259	0	}
260
261		int SRP_Verify_B_mod_N(const BIGNUM B, const BIGNUM N)
262	0	{
263	0	BIGNUM *r;
264	0	BN_CTX *bn_ctx;
265	0	int ret = 0;
266
267	0	if (B == NULL \|\| N == NULL \|\| (bn_ctx = BN_CTX_new()) == NULL)
268	0	return 0;
269
270	0	if ((r = BN_new()) == NULL)
271	0	goto err;
272		/* Checks if B % N == 0 */
273	0	if (!BN_nnmod(r, B, N, bn_ctx))
274	0	goto err;
275	0	ret = !BN_is_zero(r);
276	0	err:
277	0	BN_CTX_free(bn_ctx);
278	0	BN_free(r);
279	0	return ret;
280	0	}
281
282		int SRP_Verify_A_mod_N(const BIGNUM A, const BIGNUM N)
283	0	{
284		/* Checks if A % N == 0 */
285	0	return SRP_Verify_B_mod_N(A, N);
286	0	}
287
288		static SRP_gN knowngN[] = {
289		{ "8192", &ossl_bn_generator_19, &ossl_bn_group_8192 },
290		{ "6144", &ossl_bn_generator_5, &ossl_bn_group_6144 },
291		{ "4096", &ossl_bn_generator_5, &ossl_bn_group_4096 },
292		{ "3072", &ossl_bn_generator_5, &ossl_bn_group_3072 },
293		{ "2048", &ossl_bn_generator_2, &ossl_bn_group_2048 },
294		{ "1536", &ossl_bn_generator_2, &ossl_bn_group_1536 },
295		{ "1024", &ossl_bn_generator_2, &ossl_bn_group_1024 },
296		};
297
298	0	#define KNOWN_GN_NUMBER sizeof(knowngN) / sizeof(SRP_gN)
299
300		/*
301		* Check if G and N are known parameters. The values have been generated
302		* from the IETF RFC 5054
303		*/
304		char SRP_check_known_gN_param(const BIGNUM g, const BIGNUM *N)
305	0	{
306	0	size_t i;
307	0	if ((g == NULL) \|\| (N == NULL))
308	0	return NULL;
309
310	0	for (i = 0; i < KNOWN_GN_NUMBER; i++) {
311	0	if (BN_cmp(knowngN[i].g, g) == 0 && BN_cmp(knowngN[i].N, N) == 0)
312	0	return knowngN[i].id;
313	0	}
314	0	return NULL;
315	0	}
316
317		SRP_gN SRP_get_default_gN(const char id)
318	0	{
319	0	size_t i;
320
321	0	if (id == NULL)
322	0	return knowngN;
323	0	for (i = 0; i < KNOWN_GN_NUMBER; i++) {
324	0	if (strcmp(knowngN[i].id, id) == 0)
325	0	return knowngN + i;
326	0	}
327	0	return NULL;
328	0	}
329		#endif