Re: module ref count

[Stephan Mueller <smueller@chronox.de>]

Am Dienstag, 21. April 2015, 14:35:47 schrieb Stephan Mueller:

Hi Stephan,

> Hi Herbert,
> 
> I am currently working on the template for SP800-38F key wrapping. The
> module is operational and calculates what I want.
> 
> However, I have one problem I am having difficulties to track down and I am
> wondering whether you could point me to the right direction.
> 
> When a caller calls
> 
> 	crypto_alloc_aead("kw(aes)", 0, 0);
> 
> somehow the refcount of the kernel module implementing the keywrapping is
> not increased. Once can see that in lsmod where the "Used by" value remains
> 0.
> 
> Then when the caller deallocates the cipher handle, the refcount is -1
> according to lsmod. With that, a second invocation of crypto_alloc_aead will
> fail and I even cannot remove the module from the kernel.
> 
> Who increases the refcount on the kernel crypto API side?

I think I hit an even bigger problem: while playing with other AEAD ciphers, I 
see the same thing now:

$ lsmod 
Module                  Size  Used by
ansi_cprng             12989  0 
drbg                   30255  0 
algif_rng              12753  0 
seqiv                  13003  -1 
ccm                    17731  -1 
gcm                    23371  -1

Allocation of these ciphers fail.


> 
> Thanks a lot


-- 
Ciao
Stephan