Re: [PATCH v3] crypto: AF_ALG - remove locking in async callback

On Fri, 24 Nov 2017 17:04:19 +0100
Stephan Mueller [off-list ref] wrote:

Am Freitag, 24. November 2017, 08:37:39 CET schrieb Herbert Xu:

Hi Herbert,

quoted

On Fri, Nov 10, 2017 at 01:20:55PM +0100, Stephan Müller wrote:  

quoted

The code paths protected by the socket-lock do not use or modify the
socket in a non-atomic fashion. The actions pertaining the socket do not
even need to be handled as an atomic operation. Thus, the socket-lock
can be safely ignored.

This fixes a bug regarding scheduling in atomic as the callback function
may be invoked in interrupt context.

In addition, the sock_hold is moved before the AIO encrypt/decrypt
operation to ensure that the socket is always present. This avoids a
tiny race window where the socket is unprotected and yet used by the AIO
operation.

Finally, the release of resources for a crypto operation is moved into a
common function of af_alg_free_resources.

Fixes: e870456d8e7c8 ("crypto: algif_skcipher - overhaul memory
management") Fixes: d887c52d6ae43 ("crypto: algif_aead - overhaul memory
management") Reported-by: Romain Izard [off-list ref]
Signed-off-by: Stephan Mueller <redacted>  

Patch applied.  Thanks.  

Thanks a lot.

Would it make sense to feed it to stable?

Ciao
Stephan

My view would be definitely.  Ran into this precise issue whilst testing
a new driver 4.14 today...

Jonathan