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[NETFILTER]: xt_time: fix failure to match on Sundays

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From: Andrew Schulman <andrex@alumni.utexas.net>

xt_time_match() in net/netfilter/xt_time.c in kernel 2.6.24 never
matches on Sundays. On my host I have a rule like

    iptables -A OUTPUT -m time --weekdays Sun -j REJECT

and it never matches. The problem is in localtime_2(), which uses

    r->weekday = (4 + r->dse) % 7;

to map the epoch day onto a weekday in {0,...,6}. In particular this
gives 0 for Sundays. But 0 has to be wrong; a weekday of 0 can never
match. xt_time_match() has

    if (!(info->weekdays_match & (1 << current_time.weekday)))
        return false;

and when current_time.weekday = 0, the result of the & is always
zero, even when info->weekdays_match = XT_TIME_ALL_WEEKDAYS = 0xFE.

Signed-off-by: Jan Engelhardt <jengelh@computergmbh.de>
Signed-off-by: Patrick McHardy <kaber@trash.net>
Signed-off-by: David S. Miller <davem@davemloft.net>
This commit is contained in:
Jan Engelhardt 2008-03-10 16:42:40 -07:00 committed by David S. Miller
parent 7000d38d61
commit 4f4c9430cf
1 changed files with 5 additions and 2 deletions
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7
net/netfilter/xt_time.c
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@ -95,8 +95,11 @@ static inline void localtime_2(struct xtm *r, time_t time)
*/
r->dse = time / 86400;
/* 1970-01-01 (w=0) was a Thursday (4). */
r->weekday = (4 + r->dse) % 7;
/*
* 1970-01-01 (w=0) was a Thursday (4).
* -1 and +1 map Sunday properly onto 7.
*/
r->weekday = (4 + r->dse - 1) % 7 + 1;
}
static void localtime_3(struct xtm *r, time_t time)