GIT: unionfs2-2.6.27.y: b44 WOL setup: one-bit-off stack corruption kernel panic fix

[Erez Zadok]

commit 68cd8670ee25e0d6b0a7472672dcd3843f70a1c6
Author: Stanislav Brabec <sbrabec at suse.cz>
Date:   Tue Dec 8 21:00:22 2009 -0800

    b44 WOL setup: one-bit-off stack corruption kernel panic fix
    
    commit e0188829cb724e7d12a2d4e343b368ff1d6e1471 upstream.
    
    About 50% of shutdowns of b44 Ethernet adapter ends by kernel panic
    with kernels compiled with stack-protector.
    
    Checking b44_magic_pattern() return values, one call of
    b44_magic_pattern() returns 127. It means, that set_bit(128, pmask)
    was called on line 1509. It means that bit 0 of 17th byte of pmask was
    overwritten. But pmask has only 16 bytes. Stack corruption happens.
    
    It seems that set_bit() on line 1509 always writes one bit off.
    
    The fix does not only solve the stack corruption, but also makes Wake
    On LAN working on my onboard B44 on Asus A7V-333X mainboard.
    
    It seems that this problem affects all kernel versions since commit
    725ad800 ([PATCH] b44: add wol for old nic) on 2006-06-20.
    
    Signed-off-by: Stanislav Brabec <sbrabec at suse.cz>
    Signed-off-by: David S. Miller <davem at davemloft.net>
    Signed-off-by: Greg Kroah-Hartman <gregkh at suse.de>

diff --git a/drivers/net/b44.c b/drivers/net/b44.c
index f1521c6..012614e 100644
--- a/drivers/net/b44.c
+++ b/drivers/net/b44.c
@@ -1502,8 +1502,7 @@ static int b44_magic_pattern(u8 *macaddr, u8 *ppattern, u8 *pmask, int offset)
 		for (k = 0; k< ethaddr_bytes; k++) {
 			ppattern[offset + magicsync +
 				(j * ETH_ALEN) + k] = macaddr[k];
-			len++;
-			set_bit(len, (unsigned long *) pmask);
+			set_bit(len++, (unsigned long *) pmask);
 		}
 	}
 	return len - 1;