Thread (19 messages) 19 messages, 3 authors, 2018-07-19

Re: [dm-devel] [PATCH v5 05/11] crypto: ahash: Remove VLA usage

From: Kees Cook <hidden>
Date: 2018-07-19 03:14:12
Also in: dm-devel, lkml

On Tue, Jul 17, 2018 at 4:12 PM, Eric Biggers [off-list ref] wrote:
I just don't see why ahash algorithms would need such a huge maximum digest
size.  Don't the 'ahash' algorithms all have 'shash' equivalents too?  Is there
actually any hash algorithm, either shash or ahash, in the Linux kernel that has
a digest size greater than 64 bytes (512 bits)?  Note that for a real
cryptographic hash there isn't really any need for a digest size larger than
that, since that already gives you 256-bit collision resistance; that's why
SHA-2 and SHA-3 max out at that size.
Yup, it certainly looks that way on investigation. I'll adjust both
ahash and shash to use the same #define.

-Kees

-- 
Kees Cook
Pixel Security
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