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Commit | Line | Data |
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aa6bb135 | 1 | /* |
a38c878c | 2 | * Copyright 1995-2019 The OpenSSL Project Authors. All Rights Reserved. |
d02b48c6 | 3 | * |
e38873f5 | 4 | * Licensed under the Apache License 2.0 (the "License"). You may not use |
aa6bb135 RS |
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 | |
d02b48c6 RE |
8 | */ |
9 | ||
10 | #include <stdio.h> | |
b39fc560 | 11 | #include "internal/cryptlib.h" |
ec577822 | 12 | #include <openssl/bn.h> |
0aeddcfa | 13 | #include "dh_locl.h" |
d02b48c6 | 14 | |
2500c093 JM |
15 | # define DH_NUMBER_ITERATIONS_FOR_PRIME 64 |
16 | ||
26505153 RL |
17 | /*- |
18 | * Check that p and g are suitable enough | |
19 | * | |
20 | * p is odd | |
21 | * 1 < g < p - 1 | |
22 | */ | |
b0004708 PY |
23 | int DH_check_params_ex(const DH *dh) |
24 | { | |
25 | int errflags = 0; | |
26 | ||
a38c878c BE |
27 | if (!DH_check_params(dh, &errflags)) |
28 | return 0; | |
b0004708 PY |
29 | |
30 | if ((errflags & DH_CHECK_P_NOT_PRIME) != 0) | |
31 | DHerr(DH_F_DH_CHECK_PARAMS_EX, DH_R_CHECK_P_NOT_PRIME); | |
32 | if ((errflags & DH_NOT_SUITABLE_GENERATOR) != 0) | |
33 | DHerr(DH_F_DH_CHECK_PARAMS_EX, DH_R_NOT_SUITABLE_GENERATOR); | |
34 | ||
35 | return errflags == 0; | |
36 | } | |
26505153 RL |
37 | |
38 | int DH_check_params(const DH *dh, int *ret) | |
39 | { | |
40 | int ok = 0; | |
41 | BIGNUM *tmp = NULL; | |
42 | BN_CTX *ctx = NULL; | |
43 | ||
44 | *ret = 0; | |
45 | ctx = BN_CTX_new(); | |
46 | if (ctx == NULL) | |
47 | goto err; | |
48 | BN_CTX_start(ctx); | |
49 | tmp = BN_CTX_get(ctx); | |
50 | if (tmp == NULL) | |
51 | goto err; | |
52 | ||
53 | if (!BN_is_odd(dh->p)) | |
54 | *ret |= DH_CHECK_P_NOT_PRIME; | |
55 | if (BN_is_negative(dh->g) || BN_is_zero(dh->g) || BN_is_one(dh->g)) | |
56 | *ret |= DH_NOT_SUITABLE_GENERATOR; | |
57 | if (BN_copy(tmp, dh->p) == NULL || !BN_sub_word(tmp, 1)) | |
58 | goto err; | |
59 | if (BN_cmp(dh->g, tmp) >= 0) | |
60 | *ret |= DH_NOT_SUITABLE_GENERATOR; | |
61 | ||
62 | ok = 1; | |
63 | err: | |
ce1415ed SL |
64 | BN_CTX_end(ctx); |
65 | BN_CTX_free(ctx); | |
26a7d938 | 66 | return ok; |
26505153 RL |
67 | } |
68 | ||
1d97c843 TH |
69 | /*- |
70 | * Check that p is a safe prime and | |
a38c878c | 71 | * g is a suitable generator. |
d02b48c6 | 72 | */ |
b0004708 PY |
73 | int DH_check_ex(const DH *dh) |
74 | { | |
75 | int errflags = 0; | |
76 | ||
a38c878c BE |
77 | if (!DH_check(dh, &errflags)) |
78 | return 0; | |
b0004708 PY |
79 | |
80 | if ((errflags & DH_NOT_SUITABLE_GENERATOR) != 0) | |
81 | DHerr(DH_F_DH_CHECK_EX, DH_R_NOT_SUITABLE_GENERATOR); | |
82 | if ((errflags & DH_CHECK_Q_NOT_PRIME) != 0) | |
83 | DHerr(DH_F_DH_CHECK_EX, DH_R_CHECK_Q_NOT_PRIME); | |
84 | if ((errflags & DH_CHECK_INVALID_Q_VALUE) != 0) | |
85 | DHerr(DH_F_DH_CHECK_EX, DH_R_CHECK_INVALID_Q_VALUE); | |
86 | if ((errflags & DH_CHECK_INVALID_J_VALUE) != 0) | |
87 | DHerr(DH_F_DH_CHECK_EX, DH_R_CHECK_INVALID_J_VALUE); | |
88 | if ((errflags & DH_UNABLE_TO_CHECK_GENERATOR) != 0) | |
89 | DHerr(DH_F_DH_CHECK_EX, DH_R_UNABLE_TO_CHECK_GENERATOR); | |
90 | if ((errflags & DH_CHECK_P_NOT_PRIME) != 0) | |
91 | DHerr(DH_F_DH_CHECK_EX, DH_R_CHECK_P_NOT_PRIME); | |
92 | if ((errflags & DH_CHECK_P_NOT_SAFE_PRIME) != 0) | |
93 | DHerr(DH_F_DH_CHECK_EX, DH_R_CHECK_P_NOT_SAFE_PRIME); | |
94 | ||
95 | return errflags == 0; | |
96 | } | |
d02b48c6 | 97 | |
f971ccb2 | 98 | int DH_check(const DH *dh, int *ret) |
0f113f3e | 99 | { |
748e8530 | 100 | int ok = 0, r; |
0f113f3e | 101 | BN_CTX *ctx = NULL; |
0f113f3e MC |
102 | BIGNUM *t1 = NULL, *t2 = NULL; |
103 | ||
a38c878c BE |
104 | if (!DH_check_params(dh, ret)) |
105 | return 0; | |
106 | ||
0f113f3e MC |
107 | ctx = BN_CTX_new(); |
108 | if (ctx == NULL) | |
109 | goto err; | |
110 | BN_CTX_start(ctx); | |
111 | t1 = BN_CTX_get(ctx); | |
0f113f3e MC |
112 | t2 = BN_CTX_get(ctx); |
113 | if (t2 == NULL) | |
114 | goto err; | |
d02b48c6 | 115 | |
0f113f3e MC |
116 | if (dh->q) { |
117 | if (BN_cmp(dh->g, BN_value_one()) <= 0) | |
118 | *ret |= DH_NOT_SUITABLE_GENERATOR; | |
119 | else if (BN_cmp(dh->g, dh->p) >= 0) | |
120 | *ret |= DH_NOT_SUITABLE_GENERATOR; | |
121 | else { | |
122 | /* Check g^q == 1 mod p */ | |
123 | if (!BN_mod_exp(t1, dh->g, dh->q, dh->p, ctx)) | |
124 | goto err; | |
125 | if (!BN_is_one(t1)) | |
126 | *ret |= DH_NOT_SUITABLE_GENERATOR; | |
127 | } | |
2500c093 | 128 | r = BN_is_prime_ex(dh->q, DH_NUMBER_ITERATIONS_FOR_PRIME, ctx, NULL); |
748e8530 DB |
129 | if (r < 0) |
130 | goto err; | |
131 | if (!r) | |
0f113f3e MC |
132 | *ret |= DH_CHECK_Q_NOT_PRIME; |
133 | /* Check p == 1 mod q i.e. q divides p - 1 */ | |
134 | if (!BN_div(t1, t2, dh->p, dh->q, ctx)) | |
135 | goto err; | |
136 | if (!BN_is_one(t2)) | |
137 | *ret |= DH_CHECK_INVALID_Q_VALUE; | |
138 | if (dh->j && BN_cmp(dh->j, t1)) | |
139 | *ret |= DH_CHECK_INVALID_J_VALUE; | |
a38c878c | 140 | } |
d02b48c6 | 141 | |
2500c093 | 142 | r = BN_is_prime_ex(dh->p, DH_NUMBER_ITERATIONS_FOR_PRIME, ctx, NULL); |
748e8530 DB |
143 | if (r < 0) |
144 | goto err; | |
145 | if (!r) | |
0f113f3e MC |
146 | *ret |= DH_CHECK_P_NOT_PRIME; |
147 | else if (!dh->q) { | |
148 | if (!BN_rshift1(t1, dh->p)) | |
149 | goto err; | |
2500c093 | 150 | r = BN_is_prime_ex(t1, DH_NUMBER_ITERATIONS_FOR_PRIME, ctx, NULL); |
748e8530 DB |
151 | if (r < 0) |
152 | goto err; | |
e705fcf1 | 153 | if (!r) |
0f113f3e MC |
154 | *ret |= DH_CHECK_P_NOT_SAFE_PRIME; |
155 | } | |
156 | ok = 1; | |
157 | err: | |
ce1415ed SL |
158 | BN_CTX_end(ctx); |
159 | BN_CTX_free(ctx); | |
26a7d938 | 160 | return ok; |
0f113f3e | 161 | } |
bf3d6c0c | 162 | |
b0004708 PY |
163 | int DH_check_pub_key_ex(const DH *dh, const BIGNUM *pub_key) |
164 | { | |
165 | int errflags = 0; | |
166 | ||
167 | (void)DH_check(dh, &errflags); | |
168 | ||
169 | if ((errflags & DH_CHECK_PUBKEY_TOO_SMALL) != 0) | |
170 | DHerr(DH_F_DH_CHECK_PUB_KEY_EX, DH_R_CHECK_PUBKEY_TOO_SMALL); | |
171 | if ((errflags & DH_CHECK_PUBKEY_TOO_LARGE) != 0) | |
172 | DHerr(DH_F_DH_CHECK_PUB_KEY_EX, DH_R_CHECK_PUBKEY_TOO_LARGE); | |
173 | if ((errflags & DH_CHECK_PUBKEY_INVALID) != 0) | |
174 | DHerr(DH_F_DH_CHECK_PUB_KEY_EX, DH_R_CHECK_PUBKEY_INVALID); | |
175 | ||
176 | return errflags == 0; | |
177 | } | |
178 | ||
bf3d6c0c | 179 | int DH_check_pub_key(const DH *dh, const BIGNUM *pub_key, int *ret) |
0f113f3e MC |
180 | { |
181 | int ok = 0; | |
b128abc3 MC |
182 | BIGNUM *tmp = NULL; |
183 | BN_CTX *ctx = NULL; | |
bf3d6c0c | 184 | |
0f113f3e | 185 | *ret = 0; |
b128abc3 MC |
186 | ctx = BN_CTX_new(); |
187 | if (ctx == NULL) | |
0f113f3e | 188 | goto err; |
b128abc3 MC |
189 | BN_CTX_start(ctx); |
190 | tmp = BN_CTX_get(ctx); | |
f5a12207 | 191 | if (tmp == NULL || !BN_set_word(tmp, 1)) |
b128abc3 | 192 | goto err; |
b128abc3 | 193 | if (BN_cmp(pub_key, tmp) <= 0) |
0f113f3e | 194 | *ret |= DH_CHECK_PUBKEY_TOO_SMALL; |
f5a12207 MC |
195 | if (BN_copy(tmp, dh->p) == NULL || !BN_sub_word(tmp, 1)) |
196 | goto err; | |
b128abc3 | 197 | if (BN_cmp(pub_key, tmp) >= 0) |
0f113f3e | 198 | *ret |= DH_CHECK_PUBKEY_TOO_LARGE; |
bf3d6c0c | 199 | |
b128abc3 MC |
200 | if (dh->q != NULL) { |
201 | /* Check pub_key^q == 1 mod p */ | |
202 | if (!BN_mod_exp(tmp, pub_key, dh->q, dh->p, ctx)) | |
203 | goto err; | |
204 | if (!BN_is_one(tmp)) | |
205 | *ret |= DH_CHECK_PUBKEY_INVALID; | |
206 | } | |
207 | ||
0f113f3e MC |
208 | ok = 1; |
209 | err: | |
ce1415ed SL |
210 | BN_CTX_end(ctx); |
211 | BN_CTX_free(ctx); | |
26a7d938 | 212 | return ok; |
0f113f3e | 213 | } |