Bug report: _gcry_fast_random_poll() sets local variable to NULL (maybe we shouldn't)

[Lew Palm]

Hi gcrypt folks,

I observed our libgcrypt-based 64-bit application crashing on Windows 7
with segfaults. We use a current libgcrypt version from the git repo
(40a7bdf50e19faaf106470897fed72af623adc50).

I hunted down the problem to md_open() in md.c, line 369:
*h = hd;

h is a NULL pointer in that situation. But why?

_gcry_fast_random_poll() (md.c, line 358) is the evildoer! Before the
_gcry_fast_random_poll() call, h points to something reasonable, but
after this call it points to NULL.

_gcry_fast_random_poll() seems to do something nasty with the stack.

Regards,
  Lew

-- 
Dipl.-Inf. Lew Palm
Softwareentwicklung

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