Bodo Moeller wrote:
>
>
> The clean way (and not just another "clever hack") would be
>
> void SSL_CTX_set_tmp_rsa_callback(SSL_CTX *ctx,RSA *(*cb)(SSL *ssl,
> int is_export,
> int keylength))
> {
> RSA *(**cb_ptr)(SSL *, int, int) = &cb; /* cb_ptr is a data pointer,
> * not a function pointer */
> SSL_CTX_ctrl(ctx,SSL_CTRL_SET_TMP_RSA_CB,0,cb_ptr); /* no cast necessary as
> * SSL_CTX_ctrl should
> * have "void *" in the
> * final argument */
> }
>
> and in ssl3_ctrl (which is what SSL_CTX_ctrl ends up calling):
>
> long ssl3_ctrl(SSL *s, int cmd, long larg, void *parg)
> {
> [...]
>
> switch (cmd)
> {
> [...]
>
> case SSL_CTRL_SET_TMP_RSA_CB:
> {
> RSA *(**cb_ptr)(SSL *, int, int) = parg;
>
> s->cert->rsa_tmp_cb = *cb_ptr;
> }
> break;
> [...]
> }
> [...]
> }
>
> Instead of directly passing function pointers in disguise, a pass
> pointers to data objects containing the actual function pointers.
>
Hmmm.... that will change the SSL_ctrl() behaviour but that shouldn't be
called directly anyway.
The BIOs are a little more awkward for example we've got
BIO_set_info_callback() currently defined as a macro casting the
callback to (char *). I'd suggest we use a similar technique and zap the
macro. The macros that do this kind of thing want replacing with real
functions anyway.
It will break binary compatibility but I can't think of any alternative.
It shouldn't matter too much anyway. So much has changed since 0.9.4
most application should be recompiled anyway.
I can't think of anywhere where we have a stack of function pointers.
The EX_DATA stuff has them wrapped up in a strucure. Hmm... I've just
had a look, its a plain STACK, not STACK_OF and has no prototypes on the
function pointers either. It needs fixing.
> (SSL_CTX_ctrl, ssl3_ctrl et al. still have a char * argument where
> they should have a void * -- it's certainly trivial to change that.)
Yes thats a legacy from the pre-ANSI days. It, and a few others, should
be changed and a few (char *) casts deleted as well.
Steve.
--
Dr Stephen N. Henson. http://www.drh-consultancy.demon.co.uk/
Personal Email: [EMAIL PROTECTED]
Senior crypto engineer, Celo Communications: http://www.celocom.com/
Core developer of the OpenSSL project: http://www.openssl.org/
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