X-Git-Url: https://git.openssl.org/?p=openssl.git;a=blobdiff_plain;f=crypto%2Fdh%2Fdh_key.c;h=b6c30389767a97a57419cecc223e3614cbb36af4;hp=7576772bcd52635b7fb205a68e82ab00c6ddb15b;hb=74924dcb3802640d7e2ae2e80ca6515d0a53de7a;hpb=78414a6a897db42c9bcf06aa21c705811ab33921 diff --git a/crypto/dh/dh_key.c b/crypto/dh/dh_key.c index 7576772bcd..b6c3038976 100644 --- a/crypto/dh/dh_key.c +++ b/crypto/dh/dh_key.c @@ -5,21 +5,21 @@ * This package is an SSL implementation written * by Eric Young (eay@cryptsoft.com). * The implementation was written so as to conform with Netscapes SSL. - * + * * This library is free for commercial and non-commercial use as long as * the following conditions are aheared to. The following conditions * apply to all code found in this distribution, be it the RC4, RSA, * lhash, DES, etc., code; not just the SSL code. The SSL documentation * included with this distribution is covered by the same copyright terms * except that the holder is Tim Hudson (tjh@cryptsoft.com). - * + * * Copyright remains Eric Young's, and as such any Copyright notices in * the code are not to be removed. * If this package is used in a product, Eric Young should be given attribution * as the author of the parts of the library used. * This can be in the form of a textual message at program startup or * in documentation (online or textual) provided with the package. - * + * * Redistribution and use in source and binary forms, with or without * modification, are permitted provided that the following conditions * are met: @@ -34,10 +34,10 @@ * Eric Young (eay@cryptsoft.com)" * The word 'cryptographic' can be left out if the rouines from the library * being used are not cryptographic related :-). - * 4. If you include any Windows specific code (or a derivative thereof) from + * 4. If you include any Windows specific code (or a derivative thereof) from * the apps directory (application code) you must include an acknowledgement: * "This product includes software written by Tim Hudson (tjh@cryptsoft.com)" - * + * * THIS SOFTWARE IS PROVIDED BY ERIC YOUNG ``AS IS'' AND * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE @@ -49,7 +49,7 @@ * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF * SUCH DAMAGE. - * + * * The licence and distribution terms for any publically available version or * derivative of this code cannot be changed. i.e. this code cannot simply be * copied and put under another distribution licence @@ -57,86 +57,220 @@ */ #include -#include "cryptlib.h" -#include "bn.h" -#include "rand.h" -#include "dh.h" - -int DH_generate_key(dh) -DH *dh; - { - int ok=0; - unsigned int i; - BN_CTX *ctx=NULL; - BIGNUM *pub_key=NULL,*priv_key=NULL; - - ctx=BN_CTX_new(); - if (ctx == NULL) goto err; - - if (dh->priv_key == NULL) - { - i=dh->length; - if (i == 0) - { - /* Make the number p-1 bits long */ - i=BN_num_bits(dh->p)-1; - } - priv_key=BN_new(); - if (priv_key == NULL) goto err; - if (!BN_rand(priv_key,i,0,0)) goto err; - } - else - priv_key=dh->priv_key; - - if (dh->pub_key == NULL) - { - pub_key=BN_new(); - if (pub_key == NULL) goto err; - } - else - pub_key=dh->pub_key; - - if (!BN_mod_exp(pub_key,dh->g,priv_key,dh->p,ctx)) goto err; - - dh->pub_key=pub_key; - dh->priv_key=priv_key; - ok=1; -err: - if (ok != 1) - DHerr(DH_F_DH_GENERATE_KEY,ERR_R_BN_LIB); - - if ((pub_key != NULL) && (dh->pub_key == NULL)) BN_free(pub_key); - if ((priv_key != NULL) && (dh->priv_key == NULL)) BN_free(priv_key); - if (ctx != NULL) BN_CTX_free(ctx); - return(ok); - } - -int DH_compute_key(key,pub_key,dh) -unsigned char *key; -BIGNUM *pub_key; -DH *dh; - { - BN_CTX *ctx; - BIGNUM *tmp; - int ret= -1; - - ctx=BN_CTX_new(); - if (ctx == NULL) goto err; - tmp=ctx->bn[ctx->tos++]; - - if (dh->priv_key == NULL) - { - DHerr(DH_F_DH_COMPUTE_KEY,DH_R_NO_PRIVATE_VALUE); - goto err; - } - if (!BN_mod_exp(tmp,pub_key,dh->priv_key,dh->p,ctx)) - { - DHerr(DH_F_DH_COMPUTE_KEY,ERR_R_BN_LIB); - goto err; - } - - ret=BN_bn2bin(tmp,key); -err: - if (ctx != NULL) BN_CTX_free(ctx); - return(ret); - } +#include "internal/cryptlib.h" +#include +#include +#include "internal/bn_int.h" + +static int generate_key(DH *dh); +static int compute_key(unsigned char *key, const BIGNUM *pub_key, DH *dh); +static int dh_bn_mod_exp(const DH *dh, BIGNUM *r, + const BIGNUM *a, const BIGNUM *p, + const BIGNUM *m, BN_CTX *ctx, BN_MONT_CTX *m_ctx); +static int dh_init(DH *dh); +static int dh_finish(DH *dh); + +int DH_generate_key(DH *dh) +{ + return dh->meth->generate_key(dh); +} + +int DH_compute_key(unsigned char *key, const BIGNUM *pub_key, DH *dh) +{ + return dh->meth->compute_key(key, pub_key, dh); +} + +int DH_compute_key_padded(unsigned char *key, const BIGNUM *pub_key, DH *dh) +{ + int rv, pad; + rv = dh->meth->compute_key(key, pub_key, dh); + if (rv <= 0) + return rv; + pad = BN_num_bytes(dh->p) - rv; + if (pad > 0) { + memmove(key + pad, key, rv); + memset(key, 0, pad); + } + return rv + pad; +} + +static DH_METHOD dh_ossl = { + "OpenSSL DH Method", + generate_key, + compute_key, + dh_bn_mod_exp, + dh_init, + dh_finish, + DH_FLAG_FIPS_METHOD, + NULL, + NULL +}; + +const DH_METHOD *DH_OpenSSL(void) +{ + return &dh_ossl; +} + +static int generate_key(DH *dh) +{ + int ok = 0; + int generate_new_key = 0; + unsigned l; + BN_CTX *ctx; + BN_MONT_CTX *mont = NULL; + BIGNUM *pub_key = NULL, *priv_key = NULL; + + ctx = BN_CTX_new(); + if (ctx == NULL) + goto err; + + if (dh->priv_key == NULL) { + priv_key = BN_secure_new(); + if (priv_key == NULL) + goto err; + generate_new_key = 1; + } else + priv_key = dh->priv_key; + + if (dh->pub_key == NULL) { + pub_key = BN_new(); + if (pub_key == NULL) + goto err; + } else + pub_key = dh->pub_key; + + if (dh->flags & DH_FLAG_CACHE_MONT_P) { + mont = BN_MONT_CTX_set_locked(&dh->method_mont_p, + CRYPTO_LOCK_DH, dh->p, ctx); + if (!mont) + goto err; + } + + if (generate_new_key) { + if (dh->q) { + do { + if (!BN_rand_range(priv_key, dh->q)) + goto err; + } + while (BN_is_zero(priv_key) || BN_is_one(priv_key)); + } else { + /* secret exponent length */ + l = dh->length ? dh->length : BN_num_bits(dh->p) - 1; + if (!BN_rand(priv_key, l, 0, 0)) + goto err; + } + } + + { + BIGNUM *local_prk = NULL; + BIGNUM *prk; + + if ((dh->flags & DH_FLAG_NO_EXP_CONSTTIME) == 0) { + local_prk = prk = BN_new(); + BN_with_flags(prk, priv_key, BN_FLG_CONSTTIME); + } else + prk = priv_key; + + if (!dh->meth->bn_mod_exp(dh, pub_key, dh->g, prk, dh->p, ctx, mont)) { + BN_free(local_prk); + goto err; + } + BN_free(local_prk); + } + + dh->pub_key = pub_key; + dh->priv_key = priv_key; + ok = 1; + err: + if (ok != 1) + DHerr(DH_F_GENERATE_KEY, ERR_R_BN_LIB); + + if (pub_key != dh->pub_key) + BN_free(pub_key); + if (priv_key != dh->priv_key) + BN_free(priv_key); + BN_CTX_free(ctx); + return (ok); +} + +static int compute_key(unsigned char *key, const BIGNUM *pub_key, DH *dh) +{ + BN_CTX *ctx = NULL; + BN_MONT_CTX *mont = NULL; + BIGNUM *tmp; + int ret = -1; + int check_result; + + if (BN_num_bits(dh->p) > OPENSSL_DH_MAX_MODULUS_BITS) { + DHerr(DH_F_COMPUTE_KEY, DH_R_MODULUS_TOO_LARGE); + goto err; + } + + ctx = BN_CTX_new(); + if (ctx == NULL) + goto err; + BN_CTX_start(ctx); + tmp = BN_CTX_get(ctx); + + if (dh->priv_key == NULL) { + DHerr(DH_F_COMPUTE_KEY, DH_R_NO_PRIVATE_VALUE); + goto err; + } + + if (dh->flags & DH_FLAG_CACHE_MONT_P) { + mont = BN_MONT_CTX_set_locked(&dh->method_mont_p, + CRYPTO_LOCK_DH, dh->p, ctx); + if ((dh->flags & DH_FLAG_NO_EXP_CONSTTIME) == 0) { + /* XXX */ + BN_set_flags(dh->priv_key, BN_FLG_CONSTTIME); + } + if (!mont) + goto err; + } + + if (!DH_check_pub_key(dh, pub_key, &check_result) || check_result) { + DHerr(DH_F_COMPUTE_KEY, DH_R_INVALID_PUBKEY); + goto err; + } + + if (!dh-> + meth->bn_mod_exp(dh, tmp, pub_key, dh->priv_key, dh->p, ctx, mont)) { + DHerr(DH_F_COMPUTE_KEY, ERR_R_BN_LIB); + goto err; + } + + ret = BN_bn2bin(tmp, key); + err: + if (ctx != NULL) { + BN_CTX_end(ctx); + BN_CTX_free(ctx); + } + return (ret); +} + +static int dh_bn_mod_exp(const DH *dh, BIGNUM *r, + const BIGNUM *a, const BIGNUM *p, + const BIGNUM *m, BN_CTX *ctx, BN_MONT_CTX *m_ctx) +{ + /* + * If a is only one word long and constant time is false, use the faster + * exponenentiation function. + */ + if (bn_get_top(a) == 1 && ((dh->flags & DH_FLAG_NO_EXP_CONSTTIME) != 0)) { + BN_ULONG A = bn_get_words(a)[0]; + return BN_mod_exp_mont_word(r, A, p, m, ctx, m_ctx); + } else + return BN_mod_exp_mont(r, a, p, m, ctx, m_ctx); +} + +static int dh_init(DH *dh) +{ + dh->flags |= DH_FLAG_CACHE_MONT_P; + return (1); +} + +static int dh_finish(DH *dh) +{ + BN_MONT_CTX_free(dh->method_mont_p); + return (1); +}