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source: vbox/trunk/src/libs/openssl-3.1.3/crypto/dh/dh_check.c@ 101211

Last change on this file since 101211 was 101211, checked in by vboxsync, 17 months ago

openssl-3.1.3: Applied and adjusted our OpenSSL changes to 3.1.2. bugref:10527
File size: 9.5 KB
Line 
1/*
2 * Copyright 1995-2023 The OpenSSL Project Authors. All Rights Reserved.
3 *
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
8 */
9
10/*
11 * DH low level APIs are deprecated for public use, but still ok for
12 * internal use.
13 */
14#include "internal/deprecated.h"
15
16#include <stdio.h>
17#include "internal/cryptlib.h"
18#include <openssl/bn.h>
19#include "dh_local.h"
20#include "crypto/dh.h"
21
22/*-
23 * Check that p and g are suitable enough
24 *
25 * p is odd
26 * 1 < g < p - 1
27 */
28int DH_check_params_ex(const DH *dh)
29{
30 int errflags = 0;
31
32 if (!DH_check_params(dh, &errflags))
33 return 0;
34
35 if ((errflags & DH_CHECK_P_NOT_PRIME) != 0)
36 ERR_raise(ERR_LIB_DH, DH_R_CHECK_P_NOT_PRIME);
37 if ((errflags & DH_NOT_SUITABLE_GENERATOR) != 0)
38 ERR_raise(ERR_LIB_DH, DH_R_NOT_SUITABLE_GENERATOR);
39 if ((errflags & DH_MODULUS_TOO_SMALL) != 0)
40 ERR_raise(ERR_LIB_DH, DH_R_MODULUS_TOO_SMALL);
41 if ((errflags & DH_MODULUS_TOO_LARGE) != 0)
42 ERR_raise(ERR_LIB_DH, DH_R_MODULUS_TOO_LARGE);
43
44 return errflags == 0;
45}
46
47#ifdef FIPS_MODULE
48int DH_check_params(const DH *dh, int *ret)
49{
50 int nid;
51
52 *ret = 0;
53 /*
54 * SP800-56A R3 Section 5.5.2 Assurances of Domain Parameter Validity
55 * (1a) The domain parameters correspond to any approved safe prime group.
56 */
57 nid = DH_get_nid((DH *)dh);
58 if (nid != NID_undef)
59 return 1;
60 /*
61 * OR
62 * (2b) FFC domain params conform to FIPS-186-4 explicit domain param
63 * validity tests.
64 */
65 return ossl_ffc_params_FIPS186_4_validate(dh->libctx, &dh->params,
66 FFC_PARAM_TYPE_DH, ret, NULL);
67}
68#else
69int DH_check_params(const DH *dh, int *ret)
70{
71 int ok = 0;
72 BIGNUM *tmp = NULL;
73 BN_CTX *ctx = NULL;
74
75 *ret = 0;
76 ctx = BN_CTX_new_ex(dh->libctx);
77 if (ctx == NULL)
78 goto err;
79 BN_CTX_start(ctx);
80 tmp = BN_CTX_get(ctx);
81 if (tmp == NULL)
82 goto err;
83
84 if (!BN_is_odd(dh->params.p))
85 *ret |= DH_CHECK_P_NOT_PRIME;
86 if (BN_is_negative(dh->params.g)
87 || BN_is_zero(dh->params.g)
88 || BN_is_one(dh->params.g))
89 *ret |= DH_NOT_SUITABLE_GENERATOR;
90 if (BN_copy(tmp, dh->params.p) == NULL || !BN_sub_word(tmp, 1))
91 goto err;
92 if (BN_cmp(dh->params.g, tmp) >= 0)
93 *ret |= DH_NOT_SUITABLE_GENERATOR;
94 if (BN_num_bits(dh->params.p) < DH_MIN_MODULUS_BITS)
95 *ret |= DH_MODULUS_TOO_SMALL;
96 if (BN_num_bits(dh->params.p) > OPENSSL_DH_MAX_MODULUS_BITS)
97 *ret |= DH_MODULUS_TOO_LARGE;
98
99 ok = 1;
100 err:
101 BN_CTX_end(ctx);
102 BN_CTX_free(ctx);
103 return ok;
104}
105#endif /* FIPS_MODULE */
106
107/*-
108 * Check that p is a safe prime and
109 * g is a suitable generator.
110 */
111int DH_check_ex(const DH *dh)
112{
113 int errflags = 0;
114
115 if (!DH_check(dh, &errflags))
116 return 0;
117
118 if ((errflags & DH_NOT_SUITABLE_GENERATOR) != 0)
119 ERR_raise(ERR_LIB_DH, DH_R_NOT_SUITABLE_GENERATOR);
120 if ((errflags & DH_CHECK_Q_NOT_PRIME) != 0)
121 ERR_raise(ERR_LIB_DH, DH_R_CHECK_Q_NOT_PRIME);
122 if ((errflags & DH_CHECK_INVALID_Q_VALUE) != 0)
123 ERR_raise(ERR_LIB_DH, DH_R_CHECK_INVALID_Q_VALUE);
124 if ((errflags & DH_CHECK_INVALID_J_VALUE) != 0)
125 ERR_raise(ERR_LIB_DH, DH_R_CHECK_INVALID_J_VALUE);
126 if ((errflags & DH_UNABLE_TO_CHECK_GENERATOR) != 0)
127 ERR_raise(ERR_LIB_DH, DH_R_UNABLE_TO_CHECK_GENERATOR);
128 if ((errflags & DH_CHECK_P_NOT_PRIME) != 0)
129 ERR_raise(ERR_LIB_DH, DH_R_CHECK_P_NOT_PRIME);
130 if ((errflags & DH_CHECK_P_NOT_SAFE_PRIME) != 0)
131 ERR_raise(ERR_LIB_DH, DH_R_CHECK_P_NOT_SAFE_PRIME);
132 if ((errflags & DH_MODULUS_TOO_SMALL) != 0)
133 ERR_raise(ERR_LIB_DH, DH_R_MODULUS_TOO_SMALL);
134 if ((errflags & DH_MODULUS_TOO_LARGE) != 0)
135 ERR_raise(ERR_LIB_DH, DH_R_MODULUS_TOO_LARGE);
136
137 return errflags == 0;
138}
139
140/* Note: according to documentation - this only checks the params */
141int DH_check(const DH *dh, int *ret)
142{
143#ifdef FIPS_MODULE
144 return DH_check_params(dh, ret);
145#else
146 int ok = 0, r, q_good = 0;
147 BN_CTX *ctx = NULL;
148 BIGNUM *t1 = NULL, *t2 = NULL;
149 int nid = DH_get_nid((DH *)dh);
150
151 *ret = 0;
152 if (nid != NID_undef)
153 return 1;
154
155 /* Don't do any checks at all with an excessively large modulus */
156 if (BN_num_bits(dh->params.p) > OPENSSL_DH_CHECK_MAX_MODULUS_BITS) {
157 ERR_raise(ERR_LIB_DH, DH_R_MODULUS_TOO_LARGE);
158 *ret = DH_MODULUS_TOO_LARGE | DH_CHECK_P_NOT_PRIME;
159 return 0;
160 }
161
162 if (!DH_check_params(dh, ret))
163 return 0;
164
165 ctx = BN_CTX_new_ex(dh->libctx);
166 if (ctx == NULL)
167 goto err;
168 BN_CTX_start(ctx);
169 t1 = BN_CTX_get(ctx);
170 t2 = BN_CTX_get(ctx);
171 if (t2 == NULL)
172 goto err;
173
174 if (dh->params.q != NULL) {
175 if (BN_ucmp(dh->params.p, dh->params.q) > 0)
176 q_good = 1;
177 else
178 *ret |= DH_CHECK_INVALID_Q_VALUE;
179 }
180
181 if (q_good) {
182 if (BN_cmp(dh->params.g, BN_value_one()) <= 0)
183 *ret |= DH_NOT_SUITABLE_GENERATOR;
184 else if (BN_cmp(dh->params.g, dh->params.p) >= 0)
185 *ret |= DH_NOT_SUITABLE_GENERATOR;
186 else {
187 /* Check g^q == 1 mod p */
188 if (!BN_mod_exp(t1, dh->params.g, dh->params.q, dh->params.p, ctx))
189 goto err;
190 if (!BN_is_one(t1))
191 *ret |= DH_NOT_SUITABLE_GENERATOR;
192 }
193 r = BN_check_prime(dh->params.q, ctx, NULL);
194 if (r < 0)
195 goto err;
196 if (!r)
197 *ret |= DH_CHECK_Q_NOT_PRIME;
198 /* Check p == 1 mod q i.e. q divides p - 1 */
199 if (!BN_div(t1, t2, dh->params.p, dh->params.q, ctx))
200 goto err;
201 if (!BN_is_one(t2))
202 *ret |= DH_CHECK_INVALID_Q_VALUE;
203 if (dh->params.j != NULL
204 && BN_cmp(dh->params.j, t1))
205 *ret |= DH_CHECK_INVALID_J_VALUE;
206 }
207
208 r = BN_check_prime(dh->params.p, ctx, NULL);
209 if (r < 0)
210 goto err;
211 if (!r)
212 *ret |= DH_CHECK_P_NOT_PRIME;
213 else if (dh->params.q == NULL) {
214 if (!BN_rshift1(t1, dh->params.p))
215 goto err;
216 r = BN_check_prime(t1, ctx, NULL);
217 if (r < 0)
218 goto err;
219 if (!r)
220 *ret |= DH_CHECK_P_NOT_SAFE_PRIME;
221 }
222 ok = 1;
223 err:
224 BN_CTX_end(ctx);
225 BN_CTX_free(ctx);
226 return ok;
227#endif /* FIPS_MODULE */
228}
229
230int DH_check_pub_key_ex(const DH *dh, const BIGNUM *pub_key)
231{
232 int errflags = 0;
233
234 if (!DH_check_pub_key(dh, pub_key, &errflags))
235 return 0;
236
237 if ((errflags & DH_CHECK_PUBKEY_TOO_SMALL) != 0)
238 ERR_raise(ERR_LIB_DH, DH_R_CHECK_PUBKEY_TOO_SMALL);
239 if ((errflags & DH_CHECK_PUBKEY_TOO_LARGE) != 0)
240 ERR_raise(ERR_LIB_DH, DH_R_CHECK_PUBKEY_TOO_LARGE);
241 if ((errflags & DH_CHECK_PUBKEY_INVALID) != 0)
242 ERR_raise(ERR_LIB_DH, DH_R_CHECK_PUBKEY_INVALID);
243
244 return errflags == 0;
245}
246
247/*
248 * See SP800-56Ar3 Section 5.6.2.3.1 : FFC Full public key validation.
249 */
250int DH_check_pub_key(const DH *dh, const BIGNUM *pub_key, int *ret)
251{
252 return ossl_ffc_validate_public_key(&dh->params, pub_key, ret);
253}
254
255/*
256 * See SP800-56Ar3 Section 5.6.2.3.1 : FFC Partial public key validation.
257 * To only be used with ephemeral FFC public keys generated using the approved
258 * safe-prime groups.
259 */
260int ossl_dh_check_pub_key_partial(const DH *dh, const BIGNUM *pub_key, int *ret)
261{
262 return ossl_ffc_validate_public_key_partial(&dh->params, pub_key, ret);
263}
264
265int ossl_dh_check_priv_key(const DH *dh, const BIGNUM *priv_key, int *ret)
266{
267 int ok = 0;
268 BIGNUM *two_powN = NULL, *upper;
269
270 *ret = 0;
271 two_powN = BN_new();
272 if (two_powN == NULL)
273 return 0;
274
275 if (dh->params.q != NULL) {
276 upper = dh->params.q;
277#ifndef FIPS_MODULE
278 } else if (dh->params.p != NULL) {
279 /*
280 * We do not have q so we just check the key is within some
281 * reasonable range, or the number of bits is equal to dh->length.
282 */
283 int length = dh->length;
284
285 if (length == 0) {
286 length = BN_num_bits(dh->params.p) - 1;
287 if (BN_num_bits(priv_key) <= length
288 && BN_num_bits(priv_key) > 1)
289 ok = 1;
290 } else if (BN_num_bits(priv_key) == length) {
291 ok = 1;
292 }
293 goto end;
294#endif
295 } else {
296 goto end;
297 }
298
299 /* Is it from an approved Safe prime group ?*/
300 if (DH_get_nid((DH *)dh) != NID_undef && dh->length != 0) {
301 if (!BN_lshift(two_powN, BN_value_one(), dh->length))
302 goto end;
303 if (BN_cmp(two_powN, dh->params.q) < 0)
304 upper = two_powN;
305 }
306 if (!ossl_ffc_validate_private_key(upper, priv_key, ret))
307 goto end;
308
309 ok = 1;
310end:
311 BN_free(two_powN);
312 return ok;
313}
314
315/*
316 * FFC pairwise check from SP800-56A R3.
317 * Section 5.6.2.1.4 Owner Assurance of Pair-wise Consistency
318 */
319int ossl_dh_check_pairwise(const DH *dh)
320{
321 int ret = 0;
322 BN_CTX *ctx = NULL;
323 BIGNUM *pub_key = NULL;
324
325 if (dh->params.p == NULL
326 || dh->params.g == NULL
327 || dh->priv_key == NULL
328 || dh->pub_key == NULL)
329 return 0;
330
331 ctx = BN_CTX_new_ex(dh->libctx);
332 if (ctx == NULL)
333 goto err;
334 pub_key = BN_new();
335 if (pub_key == NULL)
336 goto err;
337
338 /* recalculate the public key = (g ^ priv) mod p */
339 if (!ossl_dh_generate_public_key(ctx, dh, dh->priv_key, pub_key))
340 goto err;
341 /* check it matches the existing pubic_key */
342 ret = BN_cmp(pub_key, dh->pub_key) == 0;
343err:
344 BN_free(pub_key);
345 BN_CTX_free(ctx);
346 return ret;
347}
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