commit f9e2bca6c22d75a289a349f869701214d63b5060
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, hilarity ensures.
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).
I personally don't understand this changelog entry:
"The message schedule W (u64[80]) is too big for the stack."
Hash context is dynamically allocated.
W[80] stack usage can be trimmed like in SHA-1, this is for separate patch.
P. S.: If only one ping flood runs, XfrmInStateProtoError will also tick
but very slowly. I personally can't explain this.
With patch applied (on BOTH sides), XfrmInStateProtoError does not tick
with multiple bidirectional ping flood streams like it doesn't tick
with SHA-1.
Signed-off-by: Alexey Dobriyan <adobriyan@xxxxxxxxx>
---
crypto/sha512_generic.c | 6 +-----
1 file changed, 1 insertion(+), 5 deletions(-)
--- a/crypto/sha512_generic.c
+++ b/crypto/sha512_generic.c
@@ -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
--
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