Commit 4f4c9430 authored Mar 10, 2008 by Jan Engelhardt Committed by David S. Miller Mar 10, 2008

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



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>

parent 7000d38d

net/netfilter/xt_time.c

+5 −2

Original line number	Diff line number	Diff line
		@@ -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)

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