Re: [PATCH v4 02/29] rxrpc: Avoid using stack memory in SG lists in rxkad
From: Herbert Xu
Date: Tue Jun 28 2016 - 03:37:56 EST
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>
Home Page: http://gondor.apana.org.au/~herbert/
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