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    Subject[10/65] crypto: sha512 - make it work, undo percpu message schedule
    3.0-stable review patch.  If anyone has any objections, please let me know.

    ------------------

    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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