Messages in this thread Patch in this message | | | Date | Wed, 01 Feb 2012 12:55:50 -0800 | From | Greg KH <> | Subject | [10/65] crypto: sha512 - make it work, undo percpu message schedule |
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3.0-stable review patch. If anyone has any objections, please let me know.
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From: Alexey Dobriyan <adobriyan@gmail.com>
commit 84e31fdb7c797a7303e0cc295cb9bc8b73fb872d upstream.
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, 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> Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
--- 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 *i 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 *i /* 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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