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author | Florian Westphal <fw@strlen.de> | 2013-09-20 20:32:55 (GMT) |
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committer | David S. Miller <davem@davemloft.net> | 2013-09-24 14:39:58 (GMT) |
commit | 8c27bd75f04fb9cb70c69c3cfe24f4e6d8e15906 (patch) | |
tree | 28156d5d01cd4393da57eb328db87d784bdd4260 /firmware | |
parent | 61f860c356c3d15b6cf48ef35beea664921dec1e (diff) | |
download | linux-fsl-qoriq-8c27bd75f04fb9cb70c69c3cfe24f4e6d8e15906.tar.xz |
tcp: syncookies: reduce cookie lifetime to 128 seconds
We currently accept cookies that were created less than 4 minutes ago
(ie, cookies with counter delta 0-3). Combined with the 8 mss table
values, this yields 32 possible values (out of 2**32) that will be valid.
Reducing the lifetime to < 2 minutes halves the guessing chance while
still providing a large enough period.
While at it, get rid of jiffies value -- they overflow too quickly on
32 bit platforms.
getnstimeofday is used to create a counter that increments every 64s.
perf shows getnstimeofday cost is negible compared to sha_transform;
normal tcp initial sequence number generation uses getnstimeofday, too.
Reported-by: Jakob Lell <jakob@jakoblell.com>
Signed-off-by: Florian Westphal <fw@strlen.de>
Signed-off-by: David S. Miller <davem@davemloft.net>
Diffstat (limited to 'firmware')
0 files changed, 0 insertions, 0 deletions