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# This file is dual licensed under the terms of the Apache License, Version
# 2.0, and the BSD License. See the LICENSE file in the root of this repository
# for complete details.
from __future__ import absolute_import, division, print_function
INCLUDES = """
#include <openssl/dh.h>
"""
TYPES = """
typedef ... DH;
const long DH_NOT_SUITABLE_GENERATOR;
"""
FUNCTIONS = """
DH *DH_new(void);
void DH_free(DH *);
int DH_size(const DH *);
int DH_generate_key(DH *);
int DH_compute_key(unsigned char *, const BIGNUM *, DH *);
DH *DHparams_dup(DH *);
/* added in 1.1.0 when the DH struct was opaqued */
void DH_get0_pqg(const DH *, const BIGNUM **, const BIGNUM **,
const BIGNUM **);
int DH_set0_pqg(DH *, BIGNUM *, BIGNUM *, BIGNUM *);
void DH_get0_key(const DH *, const BIGNUM **, const BIGNUM **);
int DH_set0_key(DH *, BIGNUM *, BIGNUM *);
int Cryptography_DH_check(const DH *, int *);
int DH_generate_parameters_ex(DH *, int, int, BN_GENCB *);
DH *d2i_DHparams_bio(BIO *, DH **);
int i2d_DHparams_bio(BIO *, DH *);
DH *Cryptography_d2i_DHxparams_bio(BIO *bp, DH **x);
int Cryptography_i2d_DHxparams_bio(BIO *bp, DH *x);
"""
CUSTOMIZATIONS = """
#if CRYPTOGRAPHY_IS_LIBRESSL
#ifndef DH_CHECK_Q_NOT_PRIME
#define DH_CHECK_Q_NOT_PRIME 0x10
#endif
#ifndef DH_CHECK_INVALID_Q_VALUE
#define DH_CHECK_INVALID_Q_VALUE 0x20
#endif
#ifndef DH_CHECK_INVALID_J_VALUE
#define DH_CHECK_INVALID_J_VALUE 0x40
#endif
/* DH_check implementation taken from OpenSSL 1.1.0pre6 */
/*-
* 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 Cryptography_DH_check(const DH *dh, int *ret)
{
int ok = 0, r;
BN_CTX *ctx = NULL;
BN_ULONG l;
BIGNUM *t1 = NULL, *t2 = NULL;
*ret = 0;
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)
*ret |= DH_NOT_SUITABLE_GENERATOR;
else if (BN_cmp(dh->g, dh->p) >= 0)
*ret |= DH_NOT_SUITABLE_GENERATOR;
else {
/* Check g^q == 1 mod p */
if (!BN_mod_exp(t1, dh->g, dh->q, dh->p, ctx))
goto err;
if (!BN_is_one(t1))
*ret |= DH_NOT_SUITABLE_GENERATOR;
}
r = BN_is_prime_ex(dh->q, BN_prime_checks, ctx, NULL);
if (r < 0)
goto err;
if (!r)
*ret |= 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))
*ret |= DH_CHECK_INVALID_Q_VALUE;
if (dh->j && BN_cmp(dh->j, t1))
*ret |= DH_CHECK_INVALID_J_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)
*ret |= DH_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))
*ret |= DH_NOT_SUITABLE_GENERATOR;
} else
*ret |= DH_UNABLE_TO_CHECK_GENERATOR;
r = BN_is_prime_ex(dh->p, BN_prime_checks, ctx, NULL);
if (r < 0)
goto err;
if (!r)
*ret |= 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, ctx, NULL);
if (r < 0)
goto err;
if (!r)
*ret |= DH_CHECK_P_NOT_SAFE_PRIME;
}
ok = 1;
err:
if (ctx != NULL) {
BN_CTX_end(ctx);
BN_CTX_free(ctx);
}
return (ok);
}
#else
int Cryptography_DH_check(const DH *dh, int *ret) {
return DH_check(dh, ret);
}
#endif
/* These functions were added in OpenSSL 1.1.0f commit d0c50e80a8 */
/* Define our own to simplify support across all versions. */
#if defined(EVP_PKEY_DHX) && EVP_PKEY_DHX != -1
DH *Cryptography_d2i_DHxparams_bio(BIO *bp, DH **x) {
return ASN1_d2i_bio_of(DH, DH_new, d2i_DHxparams, bp, x);
}
int Cryptography_i2d_DHxparams_bio(BIO *bp, DH *x) {
return ASN1_i2d_bio_of_const(DH, i2d_DHxparams, bp, x);
}
#else
DH *(*Cryptography_d2i_DHxparams_bio)(BIO *bp, DH **x) = NULL;
int (*Cryptography_i2d_DHxparams_bio)(BIO *bp, DH *x) = NULL;
#endif
"""
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