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crypto: sha512 - make it work, undo percpu message schedule

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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 commit is contained in:
Alexey Dobriyan 2012-01-14 21:27:37 +03:00 committed by Herbert Xu
parent 08c70fc3a2
commit 84e31fdb7c
1 changed files with 1 additions and 5 deletions
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6
crypto/sha512_generic.c
View file

@ -21,8 +21,6 @@
#include <linux/percpu.h>
#include <asm/byteorder.h>
static DEFINE_PER_CPU(u64[80], msg_schedule);
static inline u64 Ch(u64 x, u64 y, u64 z)
{
return z ^ (x & (y ^ z));
@ -89,7 +87,7 @@ sha512_transform(u64 *state, const u8 *input)
u64 a, b, c, d, e, f, g, h, t1, t2;
int i;
u64 *W = get_cpu_var(msg_schedule);
u64 W[80];
/* load the input */
for (i = 0; i < 16; i++)
@ -128,8 +126,6 @@ sha512_transform(u64 *state, const u8 *input)
/* erase our data */
a = b = c = d = e = f = g = h = t1 = t2 = 0;
memset(W, 0, sizeof(__get_cpu_var(msg_schedule)));
put_cpu_var(msg_schedule);
}
static int