On 14 October 2016 at 10:10, Johannes Berg <johannes@xxxxxxxxxxxxxxxx> wrote: > On Fri, 2016-10-14 at 10:05 +0100, Ard Biesheuvel wrote: >> >> Indeed. And the decrypt path does the same for auth_tag[]. > > Hadn't gotten that far, due to the BUG_ON() in CONFIG_DEBUG_SG in the > encrypt path :) > >> But that still means there are two separate problems here, one which >> affects the WPA code, and one that only affects the generic CCM >> chaining mode (but not the accelerated arm64 implementation) > > Yes. The generic CCM chaining still doesn't typically have a request on > the stack though. In fact, ESP (net/ipv4/esp4.c) for example will do > temporary allocations with kmalloc for every frame, it seems. > It is annotated with a TODO, though :-) 38320c70d282b (Herbert Xu 2008-01-28 19:35:05 -0800 41) * TODO: Use spare space in skb for this where possible. >> Unsurprisingly, I would strongly prefer those to be fixed properly >> rather than backing out my patch, but I'm happy to help out whichever >> solution we reach consensus on. > > Yeah, obviously, it would be good to use the accelerated versions after > all. > >> I will check whether this removes the issue when not using >> crypto/ccm.ko > > Ok. I think we can probably live with having those 48 bytes in per-CPU > buffers, but I suppose we don't really want to have ~500. > Agreed.
