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 ad86048a368eec84c3e78b99b9ddec116b01cc11..670727798e8c6b18dd4979f10f2769405366286a 100644 (file)
--- a/crypto/dh/dh_key.c
+++ b/crypto/dh/dh_key.c
@@ -101,19 +101,20 @@ const DH_METHOD *DH_OpenSSL(void)
 static int generate_key(DH *dh)
        {
        int ok=0;
-       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)
                {
                priv_key=BN_new();
                if (priv_key == NULL) goto err;
-               do
-                       if (!BN_rand_range(priv_key, dh->p)) goto err;
-               while (BN_is_zero(priv_key));
+               generate_new_key=1;
                }
        else
                priv_key=dh->priv_key;
@@ -130,13 +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 (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;
+               priv_key,dh->p,ctx,mont)) goto err;
                
        dh->pub_key=pub_key;
        dh->priv_key=priv_key;
@@ -147,20 +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, 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)
                {
@@ -171,12 +177,12 @@ static int compute_key(unsigned char *key, const 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 (!ENGINE_get_DH(dh->engine)->bn_mod_exp(dh, tmp, pub_key,
-                               dh->priv_key,dh->p,&ctx,mont))
+                               dh->priv_key,dh->p,ctx,mont))
                {
                DHerr(DH_F_DH_COMPUTE_KEY,ERR_R_BN_LIB);
                goto err;
@@ -184,8 +190,8 @@ static int compute_key(unsigned char *key, const 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);
        }