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Manuel Kasper wrote:
| Hello Darren,
|
| thanks for the quick source port randomization patch!
|
| While trying to apply it to m0n0wall today, two things struck me as
odd with the following code:
|
|> ! port = ipf_random() % (ntohs(np->in_pmax) -
|> ! ntohs(np->in_pmin));
|
|
| 1. np->in_pmin isn't added to the generated random number, which means
that the result will be
| between 0 and (in_pmax - in_pmin - 1), rather than between in_pmin
and in_pmax (inclusive).
|
| 2. No htons() is done on the result, and thus the resulting port
numbers don't turn out as expected.
|
| A quick test with a map rule port range of 6000:7000 resulted in port
numbers like the following (as seen on the network):
| 26114, 65282, 48898, 12033, 51459, 32258, ...
| all of which, when byte-swapped, are < 1000.
|
| The fix seems to be as follows:
|
| port = htons((ipf_random() %
| (ntohs(np->in_pmax) - ntohs(np->in_pmin) + 1))
| + ntohs(np->in_pmin));
That's what happens when you don't get enough sleep.
Darren
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