Import Bruce Schneier's Skein hashing algorithm

[allanjude]

Summary

Connects it up to username (libmd, libcrypt, sbin/md5), and the kernel (crypto.ko).
Will be connected to ZFS in a separate commit.

Test Plan

Verified against the test files

[allanjude]

Don't link sbin/md5 against both libmd and libcrypt, this was just a test to make sure it didn't break

[allanjude]

My intention was for the copy of skein in sys/crypto to only show the differences from the unmodified import, but it didn't actually work that way.

[allanjude]

Remove some future changes to sbin/md5 that slipped in

[bcr]

Found a small nit in the man page.

lib/libmd/skein.3

95

Does this single "a" have to be on an line of its own?

[cem]

I don't think it's useful to drop the skein reference files in both sys/contrib and sys/crypto. Leave them in contrib and add sys/contrib/skein to $PATH in the sys/crypto Makefile.

Does anything in the kernel use Skein? Do you intend to add anything using Skein? Skein didn't win the SHA3 contest and I don't know how much real world use it gets or will get. If we don't need it for anything, I don't think we need to import it.

lib/libmd/Makefile

99–101

Does this need to be conditional on actually compiling assembly? Does it hurt to always add these to the assembler flags?

lib/libmd/skein.3

4–7

No he didn't. Correct the copyright header. :)

91–93

Not true for short inputs or inputs where a dictionary attack is feasible, e.g. 64-bit values, first names, etc. I would just drop that sentence.

94–97

I would drop this sentence too. It's not quite a magic bullet.

sys/contrib/skein/asm/skein_block_x64.asm

1 ↗

(On Diff #15781)

I thought this was supposed to go in machine/ per the Makefiles earlier.

sys/contrib/skein/asm/skein_block_x64.s

1 ↗

(On Diff #15781)

Is this identical to skein_block_x64.asm? Why have both?

sys/contrib/skein/asm/skein_block_xmm32.s

1 ↗

(On Diff #15781)

Identical to skein_block_xmm32.asm?

sys/crypto/skein/amd64/skein_block_asm.s

1–3

Another copy of this file?!

sys/crypto/skein/brg_endian.h

2–3

I really don't think we need a second copy of this file. We have endian defines already from sys/endian.h. For the non-contrib/ directory, IMO simplify to just what is needed for FreeBSD.

sys/crypto/skein/brg_types.h

2–4

Same comment as for brg_endian.

sys/crypto/skein/skein.h

103–105

I'd prefer array-style output, e.g.,

int Skein_256_Final(Skein_256_Ctxt_t *, u08b_t[static SKEIN256_DIGEST_LENGTH]);

sys/crypto/skein/skein_freebsd.h

29–31

Drop space between * and ctx.

33–35

Use static, drop excess space between * and ctx.

[allanjude]

I think the contrib stuff should probably go in the vendor tree instead, and then just have the one copy in sys/crypto

lib/libmd/Makefile

99–101

I am not sure, I just went with what was already there.

lib/libmd/skein.3

94–97

Should change these in the md5,sha* pages too then

sys/contrib/skein/asm/skein_block_xmm32.s

1 ↗

(On Diff #15781)

different assembly dialect. Probably don't need the unused ones I guess. This was just everything from the directories that made sense in the original distribution package.

sys/crypto/skein/brg_endian.h

2–3

ok

[allanjude]

Refactor the skein import via ^/vendor-sys/skein

Much cleaner, and easier to see my local changes

[allanjude]

Fix missing manual pages for skein{256,512,1024}(1)

bump HEX_DIGEST_LENGTH

[allanjude]

Fix a mismerge

[cem]

There are a bunch of seemingly arbitrary changes to vendor/contrib code in this revision, and I don't know why.

lib/libcrypt/Makefile

43–44

Is this just a rebase, or are you including this in the Skein commit? I'd keep them separate.

lib/libmd/Makefile

12–17

same

49–65

same

lib/libmd/skein.3

94–97

Yes.

sbin/md5/md5.c

305–306

Why'd you revert this?

[allanjude]

Reduce vendor diff

[allanjude]

lib/libcrypt/Makefile

43–44

it is a rebase, the sha512t256 commit went in earlier today, which had some merge conflicts with this patch since it adds to the same makefiles.

sbin/md5/Makefile

22–25

mismerge

sbin/md5/md5.c

305–306

I didn't know if it was a good idea to change the output of all of the hashing commands.
I guess this specific bit, the benchmark, likely isn't depended upon by many scripts.

Do you think it is ok to change it to the more readable format?

[cem]

sbin/md5/md5.c

305–306

I don't think anything should depend on it... but now's the time to "break" it anyway, before 11 freezes.

[allanjude]

restore md5(1) improvements

Improve the skein(3) man page

[cem]

lib/libmd/skein.3

110

This should be a dash, not a hyphen. Does troff have a good way to format dash? Paging @wblock :).

111

This one too.

112

This one is (correctly) a hyphen!

216

Should have a newline at end of file.

[allanjude]

Switch the skein(3) man page to use em-dashes

[allanjude]

lib/libmd/skein.3

110

switched to using the proper mandoc em-dash markup

[cem]

Flawless ;-).