Re: [PATCH v4 02/29] rxrpc: Avoid using stack memory in SG lists in rxkad

[Herbert Xu]

On Tue, Jun 28, 2016 at 08:32:46AM +0100, David Howells wrote:
> Andy Lutomirski <luto@xxxxxxxxxx> wrote:
> 
> > @@ -277,6 +277,7 @@ struct rxrpc_connection {
> >  	struct key		*key;		/* security for this connection (client) */
> >  	struct key		*server_key;	/* security for this service */
> >  	struct crypto_skcipher	*cipher;	/* encryption handle */
> > +	struct rxrpc_crypt	csum_iv_head;	/* leading block for csum_iv */
> >  	struct rxrpc_crypt	csum_iv;	/* packet checksum base */
> >  	unsigned long		events;
> >  #define RXRPC_CONN_CHALLENGE	0		/* send challenge packet */
> 
> NAK.  This won't work.  csum_iv_head is per packet being processed, but you've
> put it in rxrpc_connection which is shared amongst several creators/digestors
> of packets.  Putting it in rxrpc_call won't work either since it's also needed
> for connection level packets.

Huh? If you can't write to csum_iv_head without clobbering others
then by the same reasoning you can't write to csum_iv either.  So
unless you're saying the existing code is already broken then there
is nothing wrong with the patch.
-- 
Email: Herbert Xu <herbert@xxxxxxxxxxxxxxxxxxx>
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