Re: [PATCH] mac80211: aes_ccm: move struct aead_req off the stack

2016-10-14 Thread Ard Biesheuvel
> On 14 Oct 2016, at 14:46, Johannes Berg wrote: > > >> >> Is the aad[] actually reused? I would assume it only affects the mac >> on encryption, and the verification on decryption but I don't think >> we actually need it back from the crypto routines. > > I don't

Re: [PATCH] mac80211: aes_ccm: move struct aead_req off the stack

2016-10-14 Thread Johannes Berg
> > Is the aad[] actually reused? I would assume it only affects the mac > on encryption, and the verification on decryption but I don't think > we actually need it back from the crypto routines. I don't think it's reused. > Exactly what you said above :-) My patch only touches CCM but as you

Re: [PATCH] mac80211: aes_ccm: move struct aead_req off the stack

2016-10-14 Thread Johannes Berg
On Fri, 2016-10-14 at 14:13 +0100, Ard Biesheuvel wrote: >  > > But if we allocate things anyway, is it worth expending per-CPU > > buffers on these? > > Ehmm, maybe not. I could spin a v2 that allocates a bigger buffer, > and copies aad[] into it as well Copies in/out, I guess. Also there's

Re: [PATCH] mac80211: aes_ccm: move struct aead_req off the stack

2016-10-14 Thread Ard Biesheuvel
On 14 October 2016 at 14:15, Johannes Berg wrote: > On Fri, 2016-10-14 at 14:13 +0100, Ard Biesheuvel wrote: >> >> > But if we allocate things anyway, is it worth expending per-CPU >> > buffers on these? >> >> Ehmm, maybe not. I could spin a v2 that allocates a bigger

Re: [PATCH] mac80211: aes_ccm: move struct aead_req off the stack

2016-10-14 Thread Ard Biesheuvel
On 14 October 2016 at 14:10, Johannes Berg wrote: > >> So use kzalloc > > Do we really need kzalloc()? We have things on the stack right now, and > don't initialize, so surely we don't really need to zero things? > >> This only addresses one half of the problem. The

Re: [PATCH] mac80211: aes_ccm: move struct aead_req off the stack

2016-10-14 Thread Johannes Berg
On Fri, 2016-10-14 at 15:10 +0200, Johannes Berg wrote: > > > > So use kzalloc > > Do we really need kzalloc()? We have things on the stack right now, > and don't initialize, so surely we don't really need to zero things?  Err, never mind, I'm an idiot - we *do* initialize to 0, of course.

Re: [PATCH] mac80211: aes_ccm: move struct aead_req off the stack

2016-10-14 Thread Johannes Berg
> So use kzalloc Do we really need kzalloc()? We have things on the stack right now, and don't initialize, so surely we don't really need to zero things? > This only addresses one half of the problem. The other problem, i.e., > the fact that the aad[] array lives on the stack of the caller, is