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

[Date Prev][Date Next][Thread Prev][Thread Next][Date Index][Thread Index]

 



On Tue, Jun 28, 2016 at 08:52:20AM +0100, David Howells wrote:
> Andy Lutomirski <luto@xxxxxxxxxx> wrote:
> 
> > -	skcipher_request_set_crypt(req, &sg[1], &sg[0], sizeof(tmpbuf), iv.x);
> > +	skcipher_request_set_crypt(req, &sg, &sg, sizeof(tmpbuf), iv.x);
> 
> Don't the sg's have to be different?  Aren't they both altered by the process
> of reading/writing from them?

No they don't have to be different.

> > 	struct rxrpc_skb_priv *sp;
> > ...
> > +	swap(tmpbuf.xl, *(__be64 *)sp);
> > +
> > +	sg_init_one(&sg, sp, sizeof(tmpbuf));
> 
> ????  I assume you're assuming that the rxrpc_skb_priv struct contents can
> arbitrarily replaced temporarily...

Of course you can, it's per-skb state.

> And using an XCHG-equivalent instruction?  This won't work on a 32-bit arch
> (apart from one that sports CMPXCHG8 or similar).

No this is not using an atomic xchg, whatever gave you that idea?
-- 
Email: Herbert Xu <herbert@xxxxxxxxxxxxxxxxxxx>
Home Page: http://gondor.apana.org.au/~herbert/
PGP Key: http://gondor.apana.org.au/~herbert/pubkey.txt
--
To unsubscribe from this list: send the line "unsubscribe linux-arch" in
the body of a message to majordomo@xxxxxxxxxxxxxxx
More majordomo info at  http://vger.kernel.org/majordomo-info.html



[Index of Archives]     [Linux Kernel]     [Kernel Newbies]     [x86 Platform Driver]     [Netdev]     [Linux Wireless]     [Netfilter]     [Bugtraq]     [Linux Filesystems]     [Yosemite Discussion]     [MIPS Linux]     [ARM Linux]     [Linux Security]     [Linux RAID]     [Samba]     [Device Mapper]

  Powered by Linux