/src/boringssl/crypto/fipsmodule/dh/check.c.inc

Source (jump to first uncovered line)
/* Copyright (C) 1995-1998 Eric Young (eay@cryptsoft.com)
 * All rights reserved.
 *
 * This package is an SSL implementation written
 * by Eric Young (eay@cryptsoft.com).
 * The implementation was written so as to conform with Netscapes SSL.
 *
 * This library is free for commercial and non-commercial use as long as
 * the following conditions are aheared to.  The following conditions
 * apply to all code found in this distribution, be it the RC4, RSA,
 * lhash, DES, etc., code; not just the SSL code.  The SSL documentation
 * included with this distribution is covered by the same copyright terms
 * except that the holder is Tim Hudson (tjh@cryptsoft.com).
 *
 * Copyright remains Eric Young's, and as such any Copyright notices in
 * the code are not to be removed.
 * If this package is used in a product, Eric Young should be given attribution
 * as the author of the parts of the library used.
 * This can be in the form of a textual message at program startup or
 * in documentation (online or textual) provided with the package.
 *
 * Redistribution and use in source and binary forms, with or without
 * modification, are permitted provided that the following conditions
 * are met:
 * 1. Redistributions of source code must retain the copyright
 *    notice, this list of conditions and the following disclaimer.
 * 2. Redistributions in binary form must reproduce the above copyright
 *    notice, this list of conditions and the following disclaimer in the
 *    documentation and/or other materials provided with the distribution.
 * 3. All advertising materials mentioning features or use of this software
 *    must display the following acknowledgement:
 *    "This product includes cryptographic software written by
 *     Eric Young (eay@cryptsoft.com)"
 *    The word 'cryptographic' can be left out if the rouines from the library
 *    being used are not cryptographic related :-).
 * 4. If you include any Windows specific code (or a derivative thereof) from
 *    the apps directory (application code) you must include an acknowledgement:
 *    "This product includes software written by Tim Hudson (tjh@cryptsoft.com)"
 *
 * THIS SOFTWARE IS PROVIDED BY ERIC YOUNG ``AS IS'' AND
 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
 * ARE DISCLAIMED.  IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE
 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
 * SUCH DAMAGE.
 *
 * The licence and distribution terms for any publically available version or
 * derivative of this code cannot be changed.  i.e. this code cannot simply be
 * copied and put under another distribution licence
 * [including the GNU Public Licence.] */

#include <openssl/dh.h>

#include <openssl/bn.h>
#include <openssl/err.h>

#include "internal.h"


int dh_check_params_fast(const DH *dh) {
  // Most operations scale with p and q.
  if (BN_is_negative(dh->p) || !BN_is_odd(dh->p) ||
      BN_num_bits(dh->p) > OPENSSL_DH_MAX_MODULUS_BITS) {
    OPENSSL_PUT_ERROR(DH, DH_R_INVALID_PARAMETERS);
    return 0;
  }

  // q must be bounded by p.
  if (dh->q != NULL && (BN_is_negative(dh->q) || BN_ucmp(dh->q, dh->p) > 0)) {
    OPENSSL_PUT_ERROR(DH, DH_R_INVALID_PARAMETERS);
    return 0;
  }

  // g must be an element of p's multiplicative group.
  if (BN_is_negative(dh->g) || BN_is_zero(dh->g) ||
      BN_ucmp(dh->g, dh->p) >= 0) {
    OPENSSL_PUT_ERROR(DH, DH_R_INVALID_PARAMETERS);
    return 0;
  }

  return 1;
}

int DH_check_pub_key(const DH *dh, const BIGNUM *pub_key, int *out_flags) {
  *out_flags = 0;
  if (!dh_check_params_fast(dh)) {
    return 0;
  }

  BN_CTX *ctx = BN_CTX_new();
  if (ctx == NULL) {
    return 0;
  }
  BN_CTX_start(ctx);

  int ok = 0;

  // Check |pub_key| is greater than 1.
  if (BN_cmp(pub_key, BN_value_one()) <= 0) {
    *out_flags |= DH_CHECK_PUBKEY_TOO_SMALL;
  }

  // Check |pub_key| is less than |dh->p| - 1.
  BIGNUM *tmp = BN_CTX_get(ctx);
  if (tmp == NULL ||
      !BN_copy(tmp, dh->p) ||
      !BN_sub_word(tmp, 1)) {
    goto err;
  }
  if (BN_cmp(pub_key, tmp) >= 0) {
    *out_flags |= DH_CHECK_PUBKEY_TOO_LARGE;
  }

  if (dh->q != NULL) {
    // Check |pub_key|^|dh->q| is 1 mod |dh->p|. This is necessary for RFC 5114
    // groups which are not safe primes but pick a generator on a prime-order
    // subgroup of size |dh->q|.
    if (!BN_mod_exp_mont(tmp, pub_key, dh->q, dh->p, ctx, NULL)) {
      goto err;
    }
    if (!BN_is_one(tmp)) {
      *out_flags |= DH_CHECK_PUBKEY_INVALID;
    }
  }

  ok = 1;

err:
  BN_CTX_end(ctx);
  BN_CTX_free(ctx);
  return ok;
}


int DH_check(const DH *dh, int *out_flags) {
  *out_flags = 0;
  if (!dh_check_params_fast(dh)) {
    return 0;
  }

  // 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 ok = 0, r;
  BN_CTX *ctx = NULL;
  BN_ULONG l;
  BIGNUM *t1 = NULL, *t2 = NULL;

  ctx = BN_CTX_new();
  if (ctx == NULL) {
    goto err;
  }
  BN_CTX_start(ctx);
  t1 = BN_CTX_get(ctx);
  if (t1 == NULL) {
    goto err;
  }
  t2 = BN_CTX_get(ctx);
  if (t2 == NULL) {
    goto err;
  }

  if (dh->q) {
    if (BN_cmp(dh->g, BN_value_one()) <= 0) {
      *out_flags |= DH_CHECK_NOT_SUITABLE_GENERATOR;
    } else if (BN_cmp(dh->g, dh->p) >= 0) {
      *out_flags |= DH_CHECK_NOT_SUITABLE_GENERATOR;
    } else {
      // Check g^q == 1 mod p
      if (!BN_mod_exp_mont(t1, dh->g, dh->q, dh->p, ctx, NULL)) {
        goto err;
      }
      if (!BN_is_one(t1)) {
        *out_flags |= DH_CHECK_NOT_SUITABLE_GENERATOR;
      }
    }
    r = BN_is_prime_ex(dh->q, BN_prime_checks_for_validation, ctx, NULL);
    if (r < 0) {
      goto err;
    }
    if (!r) {
      *out_flags |= 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)) {
      *out_flags |= DH_CHECK_INVALID_Q_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) {
      *out_flags |= DH_CHECK_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) {
      *out_flags |= DH_CHECK_NOT_SUITABLE_GENERATOR;
    }
  } else {
    *out_flags |= DH_CHECK_UNABLE_TO_CHECK_GENERATOR;
  }

  r = BN_is_prime_ex(dh->p, BN_prime_checks_for_validation, ctx, NULL);
  if (r < 0) {
    goto err;
  }
  if (!r) {
    *out_flags |= 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_for_validation, ctx, NULL);
    if (r < 0) {
      goto err;
    }
    if (!r) {
      *out_flags |= DH_CHECK_P_NOT_SAFE_PRIME;
    }
  }
  ok = 1;

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

Coverage Report

Created: 2024-11-21 07:03

Line	Count	Source (jump to first uncovered line)
1		/* Copyright (C) 1995-1998 Eric Young (eay@cryptsoft.com)
2		* All rights reserved.
3		*
4		* This package is an SSL implementation written
5		* by Eric Young (eay@cryptsoft.com).
6		* The implementation was written so as to conform with Netscapes SSL.
7		*
8		* This library is free for commercial and non-commercial use as long as
9		* the following conditions are aheared to. The following conditions
10		* apply to all code found in this distribution, be it the RC4, RSA,
11		* lhash, DES, etc., code; not just the SSL code. The SSL documentation
12		* included with this distribution is covered by the same copyright terms
13		* except that the holder is Tim Hudson (tjh@cryptsoft.com).
14		*
15		* Copyright remains Eric Young's, and as such any Copyright notices in
16		* the code are not to be removed.
17		* If this package is used in a product, Eric Young should be given attribution
18		* as the author of the parts of the library used.
19		* This can be in the form of a textual message at program startup or
20		* in documentation (online or textual) provided with the package.
21		*
22		* Redistribution and use in source and binary forms, with or without
23		* modification, are permitted provided that the following conditions
24		* are met:
25		* 1. Redistributions of source code must retain the copyright
26		* notice, this list of conditions and the following disclaimer.
27		* 2. Redistributions in binary form must reproduce the above copyright
28		* notice, this list of conditions and the following disclaimer in the
29		* documentation and/or other materials provided with the distribution.
30		* 3. All advertising materials mentioning features or use of this software
31		* must display the following acknowledgement:
32		* "This product includes cryptographic software written by
33		* Eric Young (eay@cryptsoft.com)"
34		* The word 'cryptographic' can be left out if the rouines from the library
35		* being used are not cryptographic related :-).
36		* 4. If you include any Windows specific code (or a derivative thereof) from
37		* the apps directory (application code) you must include an acknowledgement:
38		* "This product includes software written by Tim Hudson (tjh@cryptsoft.com)"
39		*
40		* THIS SOFTWARE IS PROVIDED BY ERIC YOUNG ``AS IS'' AND
41		* ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
42		* IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
43		* ARE DISCLAIMED. IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE
44		* FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
45		* DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
46		* OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
47		* HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
48		* LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
49		* OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
50		* SUCH DAMAGE.
51		*
52		* The licence and distribution terms for any publically available version or
53		* derivative of this code cannot be changed. i.e. this code cannot simply be
54		* copied and put under another distribution licence
55		* [including the GNU Public Licence.] */
56
57		#include <openssl/dh.h>
58
59		#include <openssl/bn.h>
60		#include <openssl/err.h>
61
62		#include "internal.h"
63
64
65	151	int dh_check_params_fast(const DH *dh) {
66		// Most operations scale with p and q.
67	151	if (BN_is_negative(dh->p) \|\| !BN_is_odd(dh->p) \|\|
68	151	BN_num_bits(dh->p) > OPENSSL_DH_MAX_MODULUS_BITS) {
69	20	OPENSSL_PUT_ERROR(DH, DH_R_INVALID_PARAMETERS);
70	20	return 0;
71	20	}
72
73		// q must be bounded by p.
74	131	if (dh->q != NULL && (BN_is_negative(dh->q) \|\| BN_ucmp(dh->q, dh->p) > 0)) {
75	0	OPENSSL_PUT_ERROR(DH, DH_R_INVALID_PARAMETERS);
76	0	return 0;
77	0	}
78
79		// g must be an element of p's multiplicative group.
80	131	if (BN_is_negative(dh->g) \|\| BN_is_zero(dh->g) \|\|
81	131	BN_ucmp(dh->g, dh->p) >= 0) {
82	18	OPENSSL_PUT_ERROR(DH, DH_R_INVALID_PARAMETERS);
83	18	return 0;
84	18	}
85
86	113	return 1;
87	131	}
88
89	37	int DH_check_pub_key(const DH dh, const BIGNUM pub_key, int *out_flags) {
90	37	*out_flags = 0;
91	37	if (!dh_check_params_fast(dh)) {
92	0	return 0;
93	0	}
94
95	37	BN_CTX *ctx = BN_CTX_new();
96	37	if (ctx == NULL) {
97	0	return 0;
98	0	}
99	37	BN_CTX_start(ctx);
100
101	37	int ok = 0;
102
103		// Check \|pub_key\| is greater than 1.
104	37	if (BN_cmp(pub_key, BN_value_one()) <= 0) {
105	5	*out_flags \|= DH_CHECK_PUBKEY_TOO_SMALL;
106	5	}
107
108		// Check \|pub_key\| is less than \|dh->p\| - 1.
109	37	BIGNUM *tmp = BN_CTX_get(ctx);
110	37	if (tmp == NULL \|\|
111	37	!BN_copy(tmp, dh->p) \|\|
112	37	!BN_sub_word(tmp, 1)) {
113	0	goto err;
114	0	}
115	37	if (BN_cmp(pub_key, tmp) >= 0) {
116	12	*out_flags \|= DH_CHECK_PUBKEY_TOO_LARGE;
117	12	}
118
119	37	if (dh->q != NULL) {
120		// Check \|pub_key\|^\|dh->q\| is 1 mod \|dh->p\|. This is necessary for RFC 5114
121		// groups which are not safe primes but pick a generator on a prime-order
122		// subgroup of size \|dh->q\|.
123	0	if (!BN_mod_exp_mont(tmp, pub_key, dh->q, dh->p, ctx, NULL)) {
124	0	goto err;
125	0	}
126	0	if (!BN_is_one(tmp)) {
127	0	*out_flags \|= DH_CHECK_PUBKEY_INVALID;
128	0	}
129	0	}
130
131	37	ok = 1;
132
133	37	err:
134	37	BN_CTX_end(ctx);
135	37	BN_CTX_free(ctx);
136	37	return ok;
137	37	}
138
139
140	0	int DH_check(const DH dh, int out_flags) {
141	0	*out_flags = 0;
142	0	if (!dh_check_params_fast(dh)) {
143	0	return 0;
144	0	}
145
146		// Check that p is a safe prime and if g is 2, 3 or 5, check that it is a
147		// suitable generator where:
148		// for 2, p mod 24 == 11
149		// for 3, p mod 12 == 5
150		// for 5, p mod 10 == 3 or 7
151		// should hold.
152	0	int ok = 0, r;
153	0	BN_CTX *ctx = NULL;
154	0	BN_ULONG l;
155	0	BIGNUM t1 = NULL, t2 = NULL;
156
157	0	ctx = BN_CTX_new();
158	0	if (ctx == NULL) {
159	0	goto err;
160	0	}
161	0	BN_CTX_start(ctx);
162	0	t1 = BN_CTX_get(ctx);
163	0	if (t1 == NULL) {
164	0	goto err;
165	0	}
166	0	t2 = BN_CTX_get(ctx);
167	0	if (t2 == NULL) {
168	0	goto err;
169	0	}
170
171	0	if (dh->q) {
172	0	if (BN_cmp(dh->g, BN_value_one()) <= 0) {
173	0	*out_flags \|= DH_CHECK_NOT_SUITABLE_GENERATOR;
174	0	} else if (BN_cmp(dh->g, dh->p) >= 0) {
175	0	*out_flags \|= DH_CHECK_NOT_SUITABLE_GENERATOR;
176	0	} else {
177		// Check g^q == 1 mod p
178	0	if (!BN_mod_exp_mont(t1, dh->g, dh->q, dh->p, ctx, NULL)) {
179	0	goto err;
180	0	}
181	0	if (!BN_is_one(t1)) {
182	0	*out_flags \|= DH_CHECK_NOT_SUITABLE_GENERATOR;
183	0	}
184	0	}
185	0	r = BN_is_prime_ex(dh->q, BN_prime_checks_for_validation, ctx, NULL);
186	0	if (r < 0) {
187	0	goto err;
188	0	}
189	0	if (!r) {
190	0	*out_flags \|= DH_CHECK_Q_NOT_PRIME;
191	0	}
192		// Check p == 1 mod q i.e. q divides p - 1
193	0	if (!BN_div(t1, t2, dh->p, dh->q, ctx)) {
194	0	goto err;
195	0	}
196	0	if (!BN_is_one(t2)) {
197	0	*out_flags \|= DH_CHECK_INVALID_Q_VALUE;
198	0	}
199	0	} else if (BN_is_word(dh->g, DH_GENERATOR_2)) {
200	0	l = BN_mod_word(dh->p, 24);
201	0	if (l == (BN_ULONG)-1) {
202	0	goto err;
203	0	}
204	0	if (l != 11) {
205	0	*out_flags \|= DH_CHECK_NOT_SUITABLE_GENERATOR;
206	0	}
207	0	} else if (BN_is_word(dh->g, DH_GENERATOR_5)) {
208	0	l = BN_mod_word(dh->p, 10);
209	0	if (l == (BN_ULONG)-1) {
210	0	goto err;
211	0	}
212	0	if (l != 3 && l != 7) {
213	0	*out_flags \|= DH_CHECK_NOT_SUITABLE_GENERATOR;
214	0	}
215	0	} else {
216	0	*out_flags \|= DH_CHECK_UNABLE_TO_CHECK_GENERATOR;
217	0	}
218
219	0	r = BN_is_prime_ex(dh->p, BN_prime_checks_for_validation, ctx, NULL);
220	0	if (r < 0) {
221	0	goto err;
222	0	}
223	0	if (!r) {
224	0	*out_flags \|= DH_CHECK_P_NOT_PRIME;
225	0	} else if (!dh->q) {
226	0	if (!BN_rshift1(t1, dh->p)) {
227	0	goto err;
228	0	}
229	0	r = BN_is_prime_ex(t1, BN_prime_checks_for_validation, ctx, NULL);
230	0	if (r < 0) {
231	0	goto err;
232	0	}
233	0	if (!r) {
234	0	*out_flags \|= DH_CHECK_P_NOT_SAFE_PRIME;
235	0	}
236	0	}
237	0	ok = 1;
238
239	0	err:
240	0	if (ctx != NULL) {
241	0	BN_CTX_end(ctx);
242	0	BN_CTX_free(ctx);
243	0	}
244	0	return ok;
245	0	}