[rtmpdump] librtmp/dh.h MDH_free(vp) using uninitialized pointer

[Reijo Tomperi]

Hi,

In file librtmp/dh.h, in function DHInit() there is this code:
failed:
   if (dh)
     MDH_free(dh);

In the same file there is also (this is on a single line):
#define MDH_free(vp)    {MDH *dh = vp; dhm_free(&dh->ctx); 
MP_free(dh->p); MP_free(dh->g); MP_free(dh->pub_key); 
MP_free(dh->priv_key); free(dh);}

When this macro is written open, it will generate code that looks like this:
MDH *dh = dh;

As you can see from the example program from below, this will result dh 
being uninitialized pointer.


-------------- code start -------------------
#include <stdio.h>

#define MDH_free(vp)    {int *aa = vp; printf("%d\n", *aa );  }
#define MDH_free2(vp)    {int *ab = vp; printf("%d\n", *ab );  }

int main()
{
     int a = 6;
     int *aa = &a;
     printf("%d\n", *aa );
     MDH_free(aa)
     MDH_free2(aa)
     return 0;
}

-------------- code end -------------------

Program output:

     6
     -1991643855
     6

-- 
Reijo