This is a first-cut at improving the callback mechanisms used in

key-generation and prime-checking functions. Rather than explicitly passing
callback functions and caller-defined context data for the callbacks, a new
structure BN_GENCB is defined that encapsulates this; a pointer to the
structure is passed to all such functions instead.

This wrapper structure allows the encapsulation of "old" and "new" style
callbacks - "new" callbacks return a boolean result on the understanding
that returning FALSE should terminate keygen/primality processing.  The
BN_GENCB abstraction will allow future callback modifications without
needing to break binary compatibility nor change the API function
prototypes. The new API functions have been given names ending in "_ex" and
the old functions are implemented as wrappers to the new ones.  The
OPENSSL_NO_DEPRECATED symbol has been introduced so that, if defined,
declaration of the older functions will be skipped. NB: Some
openssl-internal code will stick with the older callbacks for now, so
appropriate "#undef" logic will be put in place - this is in case the user
is *building* openssl (rather than *including* its headers) with this
symbol defined.

There is another change in the new _ex functions; the key-generation
functions do not return key structures but operate on structures passed by
the caller, the return value is a boolean. This will allow for a smoother
transition to having key-generation as "virtual function" in the various
***_METHOD tables.

1 files changed, 14 insertions, 17 deletions

diff --git a/crypto/dh/dh_gen.c b/crypto/dh/dh_gen.c
index 06f78b35ab..a929a0f064 100644
--- a/crypto/dh/dh_gen.c
+++ b/crypto/dh/dh_gen.c
@@ -56,6 +56,11 @@
  * [including the GNU Public Licence.]
  */
 
+/* NB: These functions have been upgraded - the previous prototypes are in
+ * dh_depr.c as wrappers to these ones.
+ *  - Geoff
+ */
+
 #include <stdio.h>
 #include "cryptlib.h"
 #include <openssl/bn.h>
@@ -86,22 +91,22 @@
  * It's just as OK (and in some sense better) to use a generator of the
  * order-q subgroup.
  */
-DH *DH_generate_parameters(int prime_len, int generator,
-	     void (*callback)(int,int,void *), void *cb_arg)
+int DH_generate_parameters_ex(DH *ret, int prime_len, int generator, BN_GENCB *cb)
 	{
-	BIGNUM *p=NULL,*t1,*t2;
-	DH *ret=NULL;
+	BIGNUM *t1,*t2;
 	int g,ok= -1;
 	BN_CTX *ctx=NULL;
 
-	ret=DH_new();
-	if (ret == NULL) goto err;
 	ctx=BN_CTX_new();
 	if (ctx == NULL) goto err;
 	BN_CTX_start(ctx);
 	t1 = BN_CTX_get(ctx);
 	t2 = BN_CTX_get(ctx);
 	if (t1 == NULL || t2 == NULL) goto err;
+
+	/* Make sure 'ret' has the necessary elements */
+	if(!ret->p && ((ret->p = BN_new()) == NULL)) goto err;
+	if(!ret->g && ((ret->g = BN_new()) == NULL)) goto err;
 	
 	if (generator <= 1)
 		{
@@ -141,11 +146,8 @@ DH *DH_generate_parameters(int prime_len, int generator,
 		g=generator;
 		}
 	
-	p=BN_generate_prime(NULL,prime_len,1,t1,t2,callback,cb_arg);
-	if (p == NULL) goto err;
-	if (callback != NULL) callback(3,0,cb_arg);
-	ret->p=p;
-	ret->g=BN_new();
+	if(!BN_generate_prime_ex(ret->p,prime_len,1,t1,t2,cb)) goto err;
+	if(!BN_GENCB_call(cb, 3, 0)) goto err;
 	if (!BN_set_word(ret->g,g)) goto err;
 	ok=1;
 err:
@@ -160,10 +162,5 @@ err:
 		BN_CTX_end(ctx);
 		BN_CTX_free(ctx);
 		}
-	if (!ok && (ret != NULL))
-		{
-		DH_free(ret);
-		ret=NULL;
-		}
-	return(ret);
+	return ok;
 	}