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, 8 insertions, 0 deletions

diff --git a/crypto/dh/dh.h b/crypto/dh/dh.h
index 05851f8429..cab9b1493d 100644
--- a/crypto/dh/dh.h
+++ b/crypto/dh/dh.h
@@ -165,8 +165,16 @@ int DH_get_ex_new_index(long argl, void *argp, CRYPTO_EX_new *new_func,
 	     CRYPTO_EX_dup *dup_func, CRYPTO_EX_free *free_func);
 int DH_set_ex_data(DH *d, int idx, void *arg);
 void *DH_get_ex_data(DH *d, int idx);
+
+/* Deprecated version */
+#ifndef OPENSSL_NO_DEPRECATED
 DH *	DH_generate_parameters(int prime_len,int generator,
 		void (*callback)(int,int,void *),void *cb_arg);
+#endif /* !defined(OPENSSL_NO_DEPRECATED) */
+
+/* New version */
+int	DH_generate_parameters_ex(DH *dh, int prime_len,int generator, BN_GENCB *cb);
+
 int	DH_check(const DH *dh,int *codes);
 int	DH_generate_key(DH *dh);
 int	DH_compute_key(unsigned char *key,const BIGNUM *pub_key,DH *dh);