diff options
| author | Jenny Guanni Qu <qguanni@gmail.com> | 2026-03-12 17:59:49 +0300 |
|---|---|---|
| committer | Florian Westphal <fw@strlen.de> | 2026-03-13 17:31:15 +0300 |
| commit | 00050ec08cecfda447e1209b388086d76addda3a (patch) | |
| tree | b9bc282e9ba474aa209eab208c58b3e71e1680a0 | |
| parent | f62a218a946b19bb59abdd5361da85fa4606b96b (diff) | |
| download | linux-00050ec08cecfda447e1209b388086d76addda3a.tar.xz | |
netfilter: xt_time: use unsigned int for monthday bit shift
The monthday field can be up to 31, and shifting a signed integer 1
by 31 positions (1 << 31) is undefined behavior in C, as the result
overflows a 32-bit signed int. Use 1U to ensure well-defined behavior
for all valid monthday values.
Change the weekday shift to 1U as well for consistency.
Fixes: ee4411a1b1e0 ("[NETFILTER]: x_tables: add xt_time match")
Reported-by: Klaudia Kloc <klaudia@vidocsecurity.com>
Reported-by: Dawid Moczadło <dawid@vidocsecurity.com>
Tested-by: Jenny Guanni Qu <qguanni@gmail.com>
Signed-off-by: Jenny Guanni Qu <qguanni@gmail.com>
Signed-off-by: Florian Westphal <fw@strlen.de>
| -rw-r--r-- | net/netfilter/xt_time.c | 4 |
1 files changed, 2 insertions, 2 deletions
diff --git a/net/netfilter/xt_time.c b/net/netfilter/xt_time.c index 00319d2a54da..d9d74011bb64 100644 --- a/net/netfilter/xt_time.c +++ b/net/netfilter/xt_time.c @@ -223,13 +223,13 @@ time_mt(const struct sk_buff *skb, struct xt_action_param *par) localtime_2(¤t_time, stamp); - if (!(info->weekdays_match & (1 << current_time.weekday))) + if (!(info->weekdays_match & (1U << current_time.weekday))) return false; /* Do not spend time computing monthday if all days match anyway */ if (info->monthdays_match != XT_TIME_ALL_MONTHDAYS) { localtime_3(¤t_time, stamp); - if (!(info->monthdays_match & (1 << current_time.monthday))) + if (!(info->monthdays_match & (1U << current_time.monthday))) return false; } |