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Subject[patch 66/76] NETFILTER: xt_time: fix failure to match on Sundays
-stable review patch.  If anyone has any objections, please let us know.
---------------------

From: Jan Engelhardt <jengelh@computergmbh.de>

Upstream commit 4f4c9430:

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: Chris Wright <chrisw@sous-sol.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
---

net/netfilter/xt_time.c | 7 +++++--
1 file changed, 5 insertions(+), 2 deletions(-)

--- a/net/netfilter/xt_time.c
+++ b/net/netfilter/xt_time.c
@@ -95,8 +95,11 @@ static inline void localtime_2(struct xt
*/
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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