st 7. 8. 2019 o 19:44 Milan Broz <gmazyland@xxxxxxxxx> napísal(a): > On 07/08/2019 17:13, Pascal Van Leeuwen wrote: > >>>> Seems there is no mistake in your code, it is some bug in aesni_intel implementation. > >>>> If I disable this module, it works as expected (with aes generic and aes_i586). > >>>> > >>> That's odd though, considering there is a dedicated xts-aes-ni implementation, > >>> i.e. I would not expect that to end up at the generic xts wrapper at all? > >> > >> Note it is 32bit system, AESNI XTS is under #ifdef CONFIG_X86_64 so it is not used. > >> > > Ok, so I guess no one bothered to make an optimized XTS version for i386. > > I quickly browsed through the code - took me a while to realise the assembly is > > "backwards" compared to the original Intel definition :-) - but I did not spot > > anything obvious :-( > > > >> I guess it only ECB part ... > > Mystery solved, the skcipher subreq must be te last member in the struct. > (Some comments in Adiantum code mentions it too, so I do not think it > just hides the corruption after the struct. Seems like another magic requirement > in crypto API :-) Oh, yes, this makes sense! I would have noticed this immediately if I had looked carefully at the struct definition :) The reason is that the skcipher_request struct is followed by a variable-length request context. So when you want to nest requests, you need to make the subrequest the last member and declare your request context size as: size of your request context struct + size of the sub-algorithm's request context. It is a bit confusing, but it is the only reasonable way to support variably sized context and at the same time keep the whole request in a single allocation. > > This chunk is enough to fix it for me: > > --- a/crypto/xts.c > +++ b/crypto/xts.c > @@ -33,8 +33,8 @@ struct xts_instance_ctx { > > struct rctx { > le128 t, tcur; > - struct skcipher_request subreq; > int rem_bytes, is_encrypt; > + struct skcipher_request subreq; > }; > > While at it, shouldn't be is_encrypt bool? > > Thanks, > Milan