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  1. 16 Feb, 2012 1 commit
  3. 05 Feb, 2012 1 commit
    • Herbert Xu's avatar
      crypto: sha512 - Avoid stack bloat on i386 · 3a92d687
      Herbert Xu authored 
      Unfortunately in reducing W from 80 to 16 we ended up unrolling
the loop twice.  As gcc has issues dealing with 64-bit ops on
i386 this means that we end up using even more stack space (>1K).

This patch solves the W reduction by moving LOAD_OP/BLEND_OP
into the loop itself, thus avoiding the need to duplicate it.

While the stack space still isn't great (>0.5K) it is at least
in the same ball park as the amount of stack used for our C sha1
implementation.

Note that this patch basically reverts to the original code so
the diff looks bigger than it really is.

Cc: stable@vger.kernel.org
Signed-off-by: default avatarHerbert Xu <herbert@gondor.apana.org.au>
      3a92d687
  5. 26 Jan, 2012 1 commit
  7. 15 Jan, 2012 2 commits
    • Alexey Dobriyan's avatar
      crypto: sha512 - reduce stack usage to safe number · 51fc6dc8
      Alexey Dobriyan authored 
      For rounds 16--79, W[i] only depends on W[i - 2], W[i - 7], W[i - 15] and W[i - 16].
Consequently, keeping all W[80] array on stack is unnecessary,
only 16 values are really needed.

Using W[16] instead of W[80] greatly reduces stack usage
(~750 bytes to ~340 bytes on x86_64).

Line by line explanation:
* BLEND_OP
  array is "circular" now, all indexes have to be modulo 16.
  Round number is positive, so remainder operation should be
  without surprises.

* initial full message scheduling is trimmed to first 16 values which
  come from data block, the rest is calculated before it's needed.

* original loop body is unrolled version of new SHA512_0_15 and
  SHA512_16_79 macros, unrolling was done to not do explicit variable
  renaming. Otherwise it's the very same code after preprocessing.
  See sha1_transform() code which does the same trick.

Patch survives in-tree crypto test and original bugreport test
(ping flood with hmac(sha512).

See FIPS 180-2 for SHA-512 definition
http://csrc.nist.gov/publications/fips/fips180-2/fips180-2withchangenotice.pdfSigned-off-by: default avatarAlexey Dobriyan <adobriyan@gmail.com>
Cc: stable@vger.kernel.org
Signed-off-by: default avatarHerbert Xu <herbert@gondor.apana.org.au>
      51fc6dc8
    • Alexey Dobriyan's avatar
      crypto: sha512 - make it work, undo percpu message schedule · 84e31fdb
      Alexey Dobriyan authored 
      commit f9e2bca6
aka "crypto: sha512 - Move message schedule W[80] to static percpu area"
created global message schedule area.

If sha512_update will ever be entered twice, hash will be silently
calculated incorrectly.

Probably the easiest way to notice incorrect hashes being calculated is
to run 2 ping floods over AH with hmac(sha512):

	#!/usr/sbin/setkey -f
	flush;
	spdflush;
	add IP1 IP2 ah 25 -A hmac-sha512 0x00000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000025;
	add IP2 IP1 ah 52 -A hmac-sha512 0x00000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000052;
	spdadd IP1 IP2 any -P out ipsec ah/transport//require;
	spdadd IP2 IP1 any -P in  ipsec ah/transport//require;

XfrmInStateProtoError will start ticking with -EBADMSG being returned
from ah_input(). This never happens with, say, hmac(sha1).

With patch applied (on BOTH sides), XfrmInStateProtoError does not tick
with multiple bidirectional ping flood streams like it doesn't tick
with SHA-1.

After this patch sha512_transform() will start using ~750 bytes of stack on x86_64.
This is OK for simple loads, for something more heavy, stack reduction will be done
separatedly.
Signed-off-by: default avatarAlexey Dobriyan <adobriyan@gmail.com>
Cc: stable@vger.kernel.org
Signed-off-by: default avatarHerbert Xu <herbert@gondor.apana.org.au>
      84e31fdb
  9. 20 Dec, 2011 15 commits
  11. 30 Nov, 2011 5 commits
  13. 21 Nov, 2011 10 commits
  15. 09 Nov, 2011 5 commits
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