Messages in this thread | | | Date | Sat, 4 Oct 2003 19:08:57 -0500 | From | Matt Mackall <> | Subject | Re: [PATCH CIFS] use CryptoAPI MD4/MD5 |
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On Sat, Oct 04, 2003 at 11:51:57AM -0700, dean gaudet wrote: > On Sat, 4 Oct 2003, Matt Mackall wrote: > > > On Sat, Oct 04, 2003 at 11:00:01AM -0700, dean gaudet wrote: > > > what about CryptoAPI is so expensive that you can't use a stack-based > > > context? > > > > The alloc functions hide a bunch of module lookup details and the size > > of the context structures vary from one alg to the next. They also > > tend to hide block-sized buffers to deal with fragments. So it's a > > little ugly but not insurmountable. > > by "block-sized" you mean like 64 bytes for MD5 and SHA1, 16 bytes for > AES, and so forth? if so that's no biggie, those are already present > in most simple library implementations of these algos. but if "block" > means 4096 bytes then, aiee.
Cipher-block-sized.
> if module lookup is expensive then perhaps a much better api would be one > which yields a module handle -- and the module handle can be used in a > much less expensive allocator to create contexts where they're required. > it seems that the module handle could be a read-only structure and > therefore shared without locking.
Indeed, I've proposed such an interface.
> this CIFS patch alone replaces 89 lines with 250 lines of code!
My experience is that aside from the context allocation/locking issues, the thing is otherwise pretty painless to work with.
-- Matt Mackall : http://www.selenic.com : of or relating to the moon - To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
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