diff options
Diffstat (limited to 'crypto/dh/dh_key.c')
| -rw-r--r-- | crypto/dh/dh_key.c | 45 |
1 files changed, 26 insertions, 19 deletions
diff --git a/crypto/dh/dh_key.c b/crypto/dh/dh_key.c index 3617e61e23..33ac134c51 100644 --- a/crypto/dh/dh_key.c +++ b/crypto/dh/dh_key.c @@ -33,15 +33,16 @@ static int dh_bn_mod_exp(const DH *dh, BIGNUM *r, static int dh_init(DH *dh); static int dh_finish(DH *dh); -static int compute_key(unsigned char *key, const BIGNUM *pub_key, DH *dh) +/* + * See SP800-56Ar3 Section 5.7.1.1 + * Finite Field Cryptography Diffie-Hellman (FFC DH) Primitive + */ +int ossl_dh_compute_key(unsigned char *key, const BIGNUM *pub_key, DH *dh) { BN_CTX *ctx = NULL; BN_MONT_CTX *mont = NULL; - BIGNUM *tmp; + BIGNUM *z = NULL, *pminus1; int ret = -1; -#ifndef FIPS_MODULE - int check_result; -#endif if (BN_num_bits(dh->params.p) > OPENSSL_DH_MAX_MODULUS_BITS) { ERR_raise(ERR_LIB_DH, DH_R_MODULUS_TOO_LARGE); @@ -57,8 +58,9 @@ static int compute_key(unsigned char *key, const BIGNUM *pub_key, DH *dh) if (ctx == NULL) goto err; BN_CTX_start(ctx); - tmp = BN_CTX_get(ctx); - if (tmp == NULL) + pminus1 = BN_CTX_get(ctx); + z = BN_CTX_get(ctx); + if (z == NULL) goto err; if (dh->priv_key == NULL) { @@ -73,22 +75,27 @@ static int compute_key(unsigned char *key, const BIGNUM *pub_key, DH *dh) if (!mont) goto err; } -/* TODO(3.0) : Solve in a PR related to Key validation for DH */ -#ifndef FIPS_MODULE - if (!DH_check_pub_key(dh, pub_key, &check_result) || check_result) { - ERR_raise(ERR_LIB_DH, DH_R_INVALID_PUBKEY); - goto err; - } -#endif - if (!dh->meth->bn_mod_exp(dh, tmp, pub_key, dh->priv_key, dh->params.p, ctx, + + /* (Step 1) Z = pub_key^priv_key mod p */ + if (!dh->meth->bn_mod_exp(dh, z, pub_key, dh->priv_key, dh->params.p, ctx, mont)) { ERR_raise(ERR_LIB_DH, ERR_R_BN_LIB); goto err; } + /* (Step 2) Error if z <= 1 or z = p - 1 */ + if (BN_copy(pminus1, dh->params.p) == NULL + || !BN_sub_word(pminus1, 1) + || BN_cmp(z, BN_value_one()) <= 0 + || BN_cmp(z, pminus1) == 0) { + ERR_raise(ERR_LIB_DH, DH_R_INVALID_SECRET); + goto err; + } + /* return the padded key, i.e. same number of bytes as the modulus */ - ret = BN_bn2binpad(tmp, key, BN_num_bytes(dh->params.p)); + ret = BN_bn2binpad(z, key, BN_num_bytes(dh->params.p)); err: + BN_clear(z); /* (Step 2) destroy intermediate values */ BN_CTX_end(ctx); BN_CTX_free(ctx); return ret; @@ -105,7 +112,7 @@ int DH_compute_key(unsigned char *key, const BIGNUM *pub_key, DH *dh) /* compute the key; ret is constant unless compute_key is external */ #ifdef FIPS_MODULE - ret = compute_key(key, pub_key, dh); + ret = ossl_dh_compute_key(key, pub_key, dh); #else ret = dh->meth->compute_key(key, pub_key, dh); #endif @@ -134,7 +141,7 @@ int DH_compute_key_padded(unsigned char *key, const BIGNUM *pub_key, DH *dh) /* rv is constant unless compute_key is external */ #ifdef FIPS_MODULE - rv = compute_key(key, pub_key, dh); + rv = ossl_dh_compute_key(key, pub_key, dh); #else rv = dh->meth->compute_key(key, pub_key, dh); #endif @@ -152,7 +159,7 @@ int DH_compute_key_padded(unsigned char *key, const BIGNUM *pub_key, DH *dh) static DH_METHOD dh_ossl = { "OpenSSL DH Method", generate_key, - compute_key, + ossl_dh_compute_key, dh_bn_mod_exp, dh_init, dh_finish, |