1 /*
2 * Copyright 2020-2024 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 #include "internal/deprecated.h"
11
12 #include <openssl/rsa.h>
13 #include <openssl/dsa.h>
14 #include <openssl/dh.h>
15 #include <openssl/ec.h>
16 #include <openssl/evp.h>
17 #include <openssl/err.h>
18 #include <openssl/proverr.h>
19 #include <openssl/core_names.h>
20 #include <openssl/obj_mac.h>
21 #include "prov/securitycheck.h"
22
23 #define OSSL_FIPS_MIN_SECURITY_STRENGTH_BITS 112
24
ossl_rsa_key_op_get_protect(const RSA * rsa,int operation,int * outprotect)25 int ossl_rsa_key_op_get_protect(const RSA *rsa, int operation, int *outprotect)
26 {
27 int protect = 0;
28
29 switch (operation) {
30 case EVP_PKEY_OP_SIGN:
31 case EVP_PKEY_OP_SIGNMSG:
32 protect = 1;
33 /* fallthrough */
34 case EVP_PKEY_OP_VERIFY:
35 case EVP_PKEY_OP_VERIFYMSG:
36 break;
37 case EVP_PKEY_OP_ENCAPSULATE:
38 case EVP_PKEY_OP_ENCRYPT:
39 protect = 1;
40 /* fallthrough */
41 case EVP_PKEY_OP_VERIFYRECOVER:
42 case EVP_PKEY_OP_DECAPSULATE:
43 case EVP_PKEY_OP_DECRYPT:
44 if (RSA_test_flags(rsa,
45 RSA_FLAG_TYPE_MASK) == RSA_FLAG_TYPE_RSASSAPSS) {
46 ERR_raise_data(ERR_LIB_PROV,
47 PROV_R_OPERATION_NOT_SUPPORTED_FOR_THIS_KEYTYPE,
48 "operation: %d", operation);
49 return 0;
50 }
51 break;
52 default:
53 ERR_raise_data(ERR_LIB_PROV, ERR_R_INTERNAL_ERROR,
54 "invalid operation: %d", operation);
55 return 0;
56 }
57 *outprotect = protect;
58 return 1;
59 }
60
61 /*
62 * FIPS requires a minimum security strength of 112 bits (for encryption or
63 * signing), and for legacy purposes 80 bits (for decryption or verifying).
64 * Set protect = 1 for encryption or signing operations, or 0 otherwise. See
65 * https://nvlpubs.nist.gov/nistpubs/SpecialPublications/NIST.SP.800-131Ar2.pdf.
66 */
ossl_rsa_check_key_size(const RSA * rsa,int protect)67 int ossl_rsa_check_key_size(const RSA *rsa, int protect)
68 {
69 int sz = RSA_bits(rsa);
70
71 if (protect ? (sz < 2048) : (sz < 1024))
72 return 0;
73 return 1;
74 }
75
76 /*
77 * FIPS requires a minimum security strength of 112 bits for key-derivation key.
78 * https://nvlpubs.nist.gov/nistpubs/SpecialPublications/NIST.SP.800-131Ar2.pdf.
79 */
ossl_kdf_check_key_size(size_t keylen)80 int ossl_kdf_check_key_size(size_t keylen)
81 {
82 return (keylen * 8) >= OSSL_FIPS_MIN_SECURITY_STRENGTH_BITS;
83 }
84
ossl_mac_check_key_size(size_t keylen)85 int ossl_mac_check_key_size(size_t keylen)
86 {
87 return ossl_kdf_check_key_size(keylen);
88 }
89
90 #ifndef OPENSSL_NO_EC
91
ossl_ec_check_curve_allowed(const EC_GROUP * group)92 int ossl_ec_check_curve_allowed(const EC_GROUP *group)
93 {
94 const char *curve_name;
95 int nid = EC_GROUP_get_curve_name(group);
96
97 /* Explicit curves are not FIPS approved */
98 if (nid == NID_undef)
99 return 0;
100 /* Only NIST curves are FIPS approved */
101 curve_name = EC_curve_nid2nist(nid);
102 if (curve_name == NULL)
103 return 0;
104 return 1;
105 }
106
107 /*
108 * In FIPS mode:
109 * protect should be 1 for any operations that need 112 bits of security
110 * strength (such as signing, and key exchange), or 0 for operations that allow
111 * a lower security strength (such as verify).
112 *
113 * For ECDH key agreement refer to SP800-56A
114 * https://nvlpubs.nist.gov/nistpubs/SpecialPublications/NIST.SP.800-56Ar3.pdf
115 * "Appendix D"
116 *
117 * For ECDSA signatures refer to
118 * https://nvlpubs.nist.gov/nistpubs/SpecialPublications/NIST.SP.800-131Ar2.pdf
119 * "Table 2"
120 */
ossl_ec_check_security_strength(const EC_GROUP * group,int protect)121 int ossl_ec_check_security_strength(const EC_GROUP *group, int protect)
122 {
123 /*
124 * For EC the security strength is the (order_bits / 2)
125 * e.g. P-224 is 112 bits.
126 */
127 int strength = EC_GROUP_order_bits(group) / 2;
128 /* The min security strength allowed for legacy verification is 80 bits */
129 if (strength < 80)
130 return 0;
131 /*
132 * For signing or key agreement only allow curves with at least 112 bits of
133 * security strength
134 */
135 if (protect && strength < OSSL_FIPS_MIN_SECURITY_STRENGTH_BITS)
136 return 0;
137 return 1;
138 }
139
140 #endif /* OPENSSL_NO_EC */
141
142 #ifndef OPENSSL_NO_DSA
143 /*
144 * Check for valid key sizes if fips mode. Refer to
145 * https://nvlpubs.nist.gov/nistpubs/SpecialPublications/NIST.SP.800-131Ar2.pdf
146 * "Table 2"
147 */
ossl_dsa_check_key(const DSA * dsa,int sign)148 int ossl_dsa_check_key(const DSA *dsa, int sign)
149 {
150 size_t L, N;
151 const BIGNUM *p, *q;
152
153 if (dsa == NULL)
154 return 0;
155
156 p = DSA_get0_p(dsa);
157 q = DSA_get0_q(dsa);
158 if (p == NULL || q == NULL)
159 return 0;
160
161 L = BN_num_bits(p);
162 N = BN_num_bits(q);
163
164 /*
165 * For Digital signature verification DSA keys with < 112 bits of
166 * security strength, are still allowed for legacy
167 * use. The bounds given in SP 800-131Ar2 - Table 2 are
168 * (512 <= L < 2048 or 160 <= N < 224).
169 *
170 * We are a little stricter and insist that both minimums are met.
171 * For example a L = 256, N = 160 key *would* be allowed by SP 800-131Ar2
172 * but we don't.
173 */
174 if (!sign) {
175 if (L < 512 || N < 160)
176 return 0;
177 if (L < 2048 || N < 224)
178 return 1;
179 }
180
181 /* Valid sizes for both sign and verify */
182 if (L == 2048 && (N == 224 || N == 256)) /* 112 bits */
183 return 1;
184 return (L == 3072 && N == 256); /* 128 bits */
185 }
186 #endif /* OPENSSL_NO_DSA */
187
188 #ifndef OPENSSL_NO_DH
189 /*
190 * For DH key agreement refer to SP800-56A
191 * https://nvlpubs.nist.gov/nistpubs/SpecialPublications/NIST.SP.800-56Ar3.pdf
192 * "Section 5.5.1.1FFC Domain Parameter Selection/Generation" and
193 * "Appendix D" FFC Safe-prime Groups
194 */
ossl_dh_check_key(const DH * dh)195 int ossl_dh_check_key(const DH *dh)
196 {
197 size_t L, N;
198 const BIGNUM *p, *q;
199
200 if (dh == NULL)
201 return 0;
202
203 p = DH_get0_p(dh);
204 q = DH_get0_q(dh);
205 if (p == NULL || q == NULL)
206 return 0;
207
208 L = BN_num_bits(p);
209 if (L < 2048)
210 return 0;
211
212 /* If it is a safe prime group then it is ok */
213 if (DH_get_nid(dh))
214 return 1;
215
216 /* If not then it must be FFC, which only allows certain sizes. */
217 N = BN_num_bits(q);
218
219 return (L == 2048 && (N == 224 || N == 256));
220 }
221 #endif /* OPENSSL_NO_DH */
222