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 #ifndef OPENSSL_HEADER_DH_H 58 #define OPENSSL_HEADER_DH_H 59 60 #include <openssl/base.h> 61 62 #include <openssl/ex_data.h> 63 #include <openssl/thread.h> 64 65 #if defined(__cplusplus) 66 extern "C" { 67 #endif 68 69 70 // DH contains functions for performing Diffie-Hellman key agreement in 71 // multiplicative groups. 72 73 74 // Allocation and destruction. 75 76 // DH_new returns a new, empty DH object or NULL on error. 77 OPENSSL_EXPORT DH *DH_new(void); 78 79 // DH_free decrements the reference count of |dh| and frees it if the reference 80 // count drops to zero. 81 OPENSSL_EXPORT void DH_free(DH *dh); 82 83 // DH_up_ref increments the reference count of |dh| and returns one. 84 OPENSSL_EXPORT int DH_up_ref(DH *dh); 85 86 87 // Properties. 88 89 // DH_get0_pub_key returns |dh|'s public key. 90 OPENSSL_EXPORT const BIGNUM *DH_get0_pub_key(const DH *dh); 91 92 // DH_get0_priv_key returns |dh|'s private key, or NULL if |dh| is a public key. 93 OPENSSL_EXPORT const BIGNUM *DH_get0_priv_key(const DH *dh); 94 95 // DH_get0_p returns |dh|'s group modulus. 96 OPENSSL_EXPORT const BIGNUM *DH_get0_p(const DH *dh); 97 98 // DH_get0_q returns the size of |dh|'s subgroup, or NULL if it is unset. 99 OPENSSL_EXPORT const BIGNUM *DH_get0_q(const DH *dh); 100 101 // DH_get0_g returns |dh|'s group generator. 102 OPENSSL_EXPORT const BIGNUM *DH_get0_g(const DH *dh); 103 104 // DH_get0_key sets |*out_pub_key| and |*out_priv_key|, if non-NULL, to |dh|'s 105 // public and private key, respectively. If |dh| is a public key, the private 106 // key will be set to NULL. 107 OPENSSL_EXPORT void DH_get0_key(const DH *dh, const BIGNUM **out_pub_key, 108 const BIGNUM **out_priv_key); 109 110 // DH_set0_key sets |dh|'s public and private key to the specified values. If 111 // NULL, the field is left unchanged. On success, it takes ownership of each 112 // argument and returns one. Otherwise, it returns zero. 113 OPENSSL_EXPORT int DH_set0_key(DH *dh, BIGNUM *pub_key, BIGNUM *priv_key); 114 115 // DH_get0_pqg sets |*out_p|, |*out_q|, and |*out_g|, if non-NULL, to |dh|'s p, 116 // q, and g parameters, respectively. 117 OPENSSL_EXPORT void DH_get0_pqg(const DH *dh, const BIGNUM **out_p, 118 const BIGNUM **out_q, const BIGNUM **out_g); 119 120 // DH_set0_pqg sets |dh|'s p, q, and g parameters to the specified values. If 121 // NULL, the field is left unchanged. On success, it takes ownership of each 122 // argument and returns one. Otherwise, it returns zero. |q| may be NULL, but 123 // |p| and |g| must either be specified or already configured on |dh|. 124 OPENSSL_EXPORT int DH_set0_pqg(DH *dh, BIGNUM *p, BIGNUM *q, BIGNUM *g); 125 126 // DH_set_length sets the number of bits to use for the secret exponent when 127 // calling |DH_generate_key| on |dh| and returns one. If unset, 128 // |DH_generate_key| will use the bit length of p. 129 OPENSSL_EXPORT int DH_set_length(DH *dh, unsigned priv_length); 130 131 132 // Standard parameters. 133 134 // BN_get_rfc3526_prime_1536 sets |*ret| to the 1536-bit MODP group from RFC 135 // 3526 and returns |ret|. If |ret| is NULL then a fresh |BIGNUM| is allocated 136 // and returned. It returns NULL on allocation failure. 137 OPENSSL_EXPORT BIGNUM *BN_get_rfc3526_prime_1536(BIGNUM *ret); 138 139 140 // Parameter generation. 141 142 #define DH_GENERATOR_2 2 143 #define DH_GENERATOR_5 5 144 145 // DH_generate_parameters_ex generates a suitable Diffie-Hellman group with a 146 // prime that is |prime_bits| long and stores it in |dh|. The generator of the 147 // group will be |generator|, which should be |DH_GENERATOR_2| unless there's a 148 // good reason to use a different value. The |cb| argument contains a callback 149 // function that will be called during the generation. See the documentation in 150 // |bn.h| about this. In addition to the callback invocations from |BN|, |cb| 151 // will also be called with |event| equal to three when the generation is 152 // complete. 153 OPENSSL_EXPORT int DH_generate_parameters_ex(DH *dh, int prime_bits, 154 int generator, BN_GENCB *cb); 155 156 157 // Diffie-Hellman operations. 158 159 // DH_generate_key generates a new, random, private key and stores it in 160 // |dh|. It returns one on success and zero on error. 161 OPENSSL_EXPORT int DH_generate_key(DH *dh); 162 163 // DH_compute_key calculates the shared key between |dh| and |peers_key| and 164 // writes it as a big-endian integer into |out|, which must have |DH_size| 165 // bytes of space. It returns the number of bytes written, or a negative number 166 // on error. 167 OPENSSL_EXPORT int DH_compute_key(uint8_t *out, const BIGNUM *peers_key, 168 DH *dh); 169 170 171 // Utility functions. 172 173 // DH_size returns the number of bytes in the DH group's prime. 174 OPENSSL_EXPORT int DH_size(const DH *dh); 175 176 // DH_num_bits returns the minimum number of bits needed to represent the 177 // absolute value of the DH group's prime. 178 OPENSSL_EXPORT unsigned DH_num_bits(const DH *dh); 179 180 #define DH_CHECK_P_NOT_PRIME 0x01 181 #define DH_CHECK_P_NOT_SAFE_PRIME 0x02 182 #define DH_CHECK_UNABLE_TO_CHECK_GENERATOR 0x04 183 #define DH_CHECK_NOT_SUITABLE_GENERATOR 0x08 184 #define DH_CHECK_Q_NOT_PRIME 0x10 185 #define DH_CHECK_INVALID_Q_VALUE 0x20 186 #define DH_CHECK_INVALID_J_VALUE 0x40 187 188 // These are compatibility defines. 189 #define DH_NOT_SUITABLE_GENERATOR DH_CHECK_NOT_SUITABLE_GENERATOR 190 #define DH_UNABLE_TO_CHECK_GENERATOR DH_CHECK_UNABLE_TO_CHECK_GENERATOR 191 192 // DH_check checks the suitability of |dh| as a Diffie-Hellman group. and sets 193 // |DH_CHECK_*| flags in |*out_flags| if it finds any errors. It returns one if 194 // |*out_flags| was successfully set and zero on error. 195 // 196 // Note: these checks may be quite computationally expensive. 197 OPENSSL_EXPORT int DH_check(const DH *dh, int *out_flags); 198 199 #define DH_CHECK_PUBKEY_TOO_SMALL 0x1 200 #define DH_CHECK_PUBKEY_TOO_LARGE 0x2 201 #define DH_CHECK_PUBKEY_INVALID 0x4 202 203 // DH_check_pub_key checks the suitability of |pub_key| as a public key for the 204 // DH group in |dh| and sets |DH_CHECK_PUBKEY_*| flags in |*out_flags| if it 205 // finds any errors. It returns one if |*out_flags| was successfully set and 206 // zero on error. 207 OPENSSL_EXPORT int DH_check_pub_key(const DH *dh, const BIGNUM *pub_key, 208 int *out_flags); 209 210 // DHparams_dup allocates a fresh |DH| and copies the parameters from |dh| into 211 // it. It returns the new |DH| or NULL on error. 212 OPENSSL_EXPORT DH *DHparams_dup(const DH *dh); 213 214 215 // ASN.1 functions. 216 217 // DH_parse_parameters decodes a DER-encoded DHParameter structure (PKCS #3) 218 // from |cbs| and advances |cbs|. It returns a newly-allocated |DH| or NULL on 219 // error. 220 OPENSSL_EXPORT DH *DH_parse_parameters(CBS *cbs); 221 222 // DH_marshal_parameters marshals |dh| as a DER-encoded DHParameter structure 223 // (PKCS #3) and appends the result to |cbb|. It returns one on success and zero 224 // on error. 225 OPENSSL_EXPORT int DH_marshal_parameters(CBB *cbb, const DH *dh); 226 227 228 // ex_data functions. 229 // 230 // See |ex_data.h| for details. 231 232 OPENSSL_EXPORT int DH_get_ex_new_index(long argl, void *argp, 233 CRYPTO_EX_unused *unused, 234 CRYPTO_EX_dup *dup_unused, 235 CRYPTO_EX_free *free_func); 236 OPENSSL_EXPORT int DH_set_ex_data(DH *d, int idx, void *arg); 237 OPENSSL_EXPORT void *DH_get_ex_data(DH *d, int idx); 238 239 240 // Deprecated functions. 241 242 // DH_generate_parameters behaves like |DH_generate_parameters_ex|, which is 243 // what you should use instead. It returns NULL on error, or a newly-allocated 244 // |DH| on success. This function is provided for compatibility only. 245 OPENSSL_EXPORT DH *DH_generate_parameters(int prime_len, int generator, 246 void (*callback)(int, int, void *), 247 void *cb_arg); 248 249 // d2i_DHparams parses an ASN.1, DER encoded Diffie-Hellman parameters structure 250 // from |len| bytes at |*inp|. If |ret| is not NULL then, on exit, a pointer to 251 // the result is in |*ret|. Note that, even if |*ret| is already non-NULL on 252 // entry, it will not be written to. Rather, a fresh |DH| is allocated and the 253 // previous one is freed. 254 // 255 // On successful exit, |*inp| is advanced past the DER structure. It 256 // returns the result or NULL on error. 257 // 258 // Use |DH_parse_parameters| instead. 259 OPENSSL_EXPORT DH *d2i_DHparams(DH **ret, const unsigned char **inp, long len); 260 261 // i2d_DHparams marshals |in| to an ASN.1, DER structure. If |outp| is not NULL 262 // then the result is written to |*outp| and |*outp| is advanced just past the 263 // output. It returns the number of bytes in the result, whether written or 264 // not, or a negative value on error. 265 // 266 // Use |DH_marshal_parameters| instead. 267 OPENSSL_EXPORT int i2d_DHparams(const DH *in, unsigned char **outp); 268 269 270 struct dh_st { 271 BIGNUM *p; 272 BIGNUM *g; 273 BIGNUM *pub_key; // g^x mod p 274 BIGNUM *priv_key; // x 275 276 // priv_length contains the length, in bits, of the private value. If zero, 277 // the private value will be the same length as |p|. 278 unsigned priv_length; 279 280 CRYPTO_MUTEX method_mont_p_lock; 281 BN_MONT_CTX *method_mont_p; 282 283 // Place holders if we want to do X9.42 DH 284 BIGNUM *q; 285 BIGNUM *j; 286 unsigned char *seed; 287 int seedlen; 288 BIGNUM *counter; 289 290 int flags; 291 CRYPTO_refcount_t references; 292 CRYPTO_EX_DATA ex_data; 293 }; 294 295 296 #if defined(__cplusplus) 297 } // extern C 298 299 extern "C++" { 300 301 BSSL_NAMESPACE_BEGIN 302 303 BORINGSSL_MAKE_DELETER(DH, DH_free) 304 BORINGSSL_MAKE_UP_REF(DH, DH_up_ref) 305 306 BSSL_NAMESPACE_END 307 308 } // extern C++ 309 310 #endif 311 312 #define DH_R_BAD_GENERATOR 100 313 #define DH_R_INVALID_PUBKEY 101 314 #define DH_R_MODULUS_TOO_LARGE 102 315 #define DH_R_NO_PRIVATE_VALUE 103 316 #define DH_R_DECODE_ERROR 104 317 #define DH_R_ENCODE_ERROR 105 318 319 #endif // OPENSSL_HEADER_DH_H 320