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.pdf
Signed-off-by: Alexey Dobriyan <adobriyan@gmail.com>
Cc: stable@vger.kernel.org
Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>
commit f9e2bca6c2
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: Alexey Dobriyan <adobriyan@gmail.com>
Cc: stable@vger.kernel.org
Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>
This patch replaces the 32-bit counters in sha512_generic with
64-bit counters. It also switches the bit count to the simpler
byte count.
Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>
This patch renames struct sha512_ctx and exports it as struct
sha512_state so that other sha512 implementations can use it
as the reference structure for exporting their state.
Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>
This patch changes sha512 and sha384 to the new shash interface.
Signed-off-by: Adrian-Ken Rueegsegger <ken@codelabs.ch>
Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>
The message schedule W (u64[80]) is too big for the stack. In order
for this algorithm to be used with shash it is moved to a static
percpu area.
Signed-off-by: Adrian-Ken Rueegsegger <ken@codelabs.ch>
Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>
On Thu, Mar 27, 2008 at 03:40:36PM +0100, Bodo Eggert wrote:
> Kamalesh Babulal <kamalesh@linux.vnet.ibm.com> wrote:
>
> > This patch cleanups the crypto code, replaces the init() and fini()
> > with the <algorithm name>_init/_fini
>
> This part ist OK.
>
> > or init/fini_<algorithm name> (if the
> > <algorithm name>_init/_fini exist)
>
> Having init_foo and foo_init won't be a good thing, will it? I'd start
> confusing them.
>
> What about foo_modinit instead?
Thanks for the suggestion, the init() is replaced with
<algorithm name>_mod_init ()
and fini () is replaced with <algorithm name>_mod_fini.
Signed-off-by: Kamalesh Babulal <kamalesh@linux.vnet.ibm.com>
Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>
Rename sha512 to sha512_generic and add a MODULE_ALIAS for sha512
so all sha512 implementations can be loaded automatically.
Keep the broken tabs so git recognizes this as a rename.
Signed-off-by: Jan Glauber <jang@linux.vnet.ibm.com>
Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>
