length of secret exponent is needed only when we create one

[openssl.git] / crypto / dh / dh_key.c

diff --git a/crypto/dh/dh_key.c b/crypto/dh/dh_key.c
index 0c7eeaf260b359e8a017cf7249f53bab239f80f0..670727798e8c6b18dd4979f10f2769405366286a 100644 (file)
--- a/crypto/dh/dh_key.c
+++ b/crypto/dh/dh_key.c
@@ -61,10 +61,12 @@
 #include <openssl/bn.h>
 #include <openssl/rand.h>
 #include <openssl/dh.h>
+#include <openssl/engine.h>
 
 static int generate_key(DH *dh);
-static int compute_key(unsigned char *key, BIGNUM *pub_key, DH *dh);
-static int dh_bn_mod_exp(DH *dh, BIGNUM *r, BIGNUM *a, const BIGNUM *p,
+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);
@@ -72,12 +74,12 @@ static int dh_finish(DH *dh);
 
 int DH_generate_key(DH *dh)
        {
-       return dh->meth->generate_key(dh);
+       return ENGINE_get_DH(dh->engine)->generate_key(dh);
        }
 
-int DH_compute_key(unsigned char *key, BIGNUM *pub_key, DH *dh)
+int DH_compute_key(unsigned char *key, const BIGNUM *pub_key, DH *dh)
        {
-       return dh->meth->compute_key(key, pub_key, dh);
+       return ENGINE_get_DH(dh->engine)->compute_key(key, pub_key, dh);
        }
 
 static DH_METHOD dh_ossl = {
@@ -91,7 +93,7 @@ dh_finish,
 NULL
 };
 
-DH_METHOD *DH_OpenSSL(void)
+const DH_METHOD *DH_OpenSSL(void)
 {
        return &dh_ossl;
 }
@@ -99,24 +101,20 @@ DH_METHOD *DH_OpenSSL(void)
 static int generate_key(DH *dh)
        {
        int ok=0;
-       unsigned int i;
-       BN_CTX ctx;
+       int generate_new_key=0;
+       unsigned l;
+       BN_CTX *ctx;
        BN_MONT_CTX *mont;
        BIGNUM *pub_key=NULL,*priv_key=NULL;
 
-       BN_CTX_init(&ctx);
+       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;
+               generate_new_key=1;
                }
        else
                priv_key=dh->priv_key;
@@ -133,12 +131,17 @@ static int generate_key(DH *dh)
                {
                if ((dh->method_mont_p=(char *)BN_MONT_CTX_new()) != NULL)
                        if (!BN_MONT_CTX_set((BN_MONT_CTX *)dh->method_mont_p,
-                               dh->p,&ctx)) goto err;
+                               dh->p,ctx)) goto err;
                }
        mont=(BN_MONT_CTX *)dh->method_mont_p;
 
-       if (!dh->meth->bn_mod_exp(dh, pub_key,dh->g,priv_key,dh->p,&ctx,mont))
-                                                               goto err;
+       if (generate_new_key)
+               {
+               l = dh->length ? dh->length : BN_num_bits(dh->p)-1; /* secret exponent length */
+               if (!BN_rand(priv_key, l, 0, 0)) goto err;
+               }
+       if (!ENGINE_get_DH(dh->engine)->bn_mod_exp(dh, pub_key, dh->g,
+               priv_key,dh->p,ctx,mont)) goto err;
                
        dh->pub_key=pub_key;
        dh->priv_key=priv_key;
@@ -149,20 +152,21 @@ err:
 
        if ((pub_key != NULL)  && (dh->pub_key == NULL))  BN_free(pub_key);
        if ((priv_key != NULL) && (dh->priv_key == NULL)) BN_free(priv_key);
-       BN_CTX_free(&ctx);
+       BN_CTX_free(ctx);
        return(ok);
        }
 
-static int compute_key(unsigned char *key, BIGNUM *pub_key, DH *dh)
+static int compute_key(unsigned char *key, const BIGNUM *pub_key, DH *dh)
        {
-       BN_CTX ctx;
+       BN_CTX *ctx;
        BN_MONT_CTX *mont;
        BIGNUM *tmp;
        int ret= -1;
 
-       BN_CTX_init(&ctx);
-       BN_CTX_start(&ctx);
-       tmp = BN_CTX_get(&ctx);
+       ctx = BN_CTX_new();
+       if (ctx == NULL) goto err;
+       BN_CTX_start(ctx);
+       tmp = BN_CTX_get(ctx);
        
        if (dh->priv_key == NULL)
                {
@@ -173,11 +177,12 @@ static int compute_key(unsigned char *key, BIGNUM *pub_key, DH *dh)
                {
                if ((dh->method_mont_p=(char *)BN_MONT_CTX_new()) != NULL)
                        if (!BN_MONT_CTX_set((BN_MONT_CTX *)dh->method_mont_p,
-                               dh->p,&ctx)) goto err;
+                               dh->p,ctx)) goto err;
                }
 
        mont=(BN_MONT_CTX *)dh->method_mont_p;
-       if (!dh->meth->bn_mod_exp(dh, tmp,pub_key,dh->priv_key,dh->p,&ctx,mont))
+       if (!ENGINE_get_DH(dh->engine)->bn_mod_exp(dh, tmp, pub_key,
+                               dh->priv_key,dh->p,ctx,mont))
                {
                DHerr(DH_F_DH_COMPUTE_KEY,ERR_R_BN_LIB);
                goto err;
@@ -185,27 +190,35 @@ static int compute_key(unsigned char *key, BIGNUM *pub_key, DH *dh)
 
        ret=BN_bn2bin(tmp,key);
 err:
-       BN_CTX_end(&ctx);
-       BN_CTX_free(&ctx);
+       BN_CTX_end(ctx);
+       BN_CTX_free(ctx);
        return(ret);
        }
 
-static int dh_bn_mod_exp(DH *dh, BIGNUM *r, BIGNUM *a, const BIGNUM *p,
+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)
-{
-       return BN_mod_exp_mont(r, a, p, m, ctx, m_ctx);
-}
+       {
+       if (a->top == 1)
+               {
+               BN_ULONG A = a->d[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)
-{
+       {
        if(dh->method_mont_p)
                BN_MONT_CTX_free((BN_MONT_CTX *)dh->method_mont_p);
        return(1);
-}
+       }