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| author | Jozsef Kadlecsik <kadlec@mail.kfki.hu> | 2021-01-29 20:57:43 +0100 |
|---|---|---|
| committer | Pablo Neira Ayuso <pablo@netfilter.org> | 2021-02-04 00:33:08 +0100 |
| commit | b1bdde33b72366da20d10770ab7a49fe87b5e190 (patch) | |
| tree | 253dfd0837307728e702e1b832a33ad14c2069d9 | |
| parent | 44a674d6f79867d5652026f1cc11f7ba8a390183 (diff) | |
| download | linux-stable-b1bdde33b72366da20d10770ab7a49fe87b5e190.tar.gz linux-stable-b1bdde33b72366da20d10770ab7a49fe87b5e190.tar.bz2 linux-stable-b1bdde33b72366da20d10770ab7a49fe87b5e190.zip | |
netfilter: xt_recent: Fix attempt to update deleted entry
When both --reap and --update flag are specified, there's a code
path at which the entry to be updated is reaped beforehand,
which then leads to kernel crash. Reap only entries which won't be
updated.
Fixes kernel bugzilla #207773.
Link: https://bugzilla.kernel.org/show_bug.cgi?id=207773
Reported-by: Reindl Harald <h.reindl@thelounge.net>
Fixes: 0079c5aee348 ("netfilter: xt_recent: add an entry reaper")
Signed-off-by: Jozsef Kadlecsik <kadlec@netfilter.org>
Signed-off-by: Pablo Neira Ayuso <pablo@netfilter.org>
| -rw-r--r-- | net/netfilter/xt_recent.c | 12 |
1 files changed, 10 insertions, 2 deletions
diff --git a/net/netfilter/xt_recent.c b/net/netfilter/xt_recent.c index 606411869698..0446307516cd 100644 --- a/net/netfilter/xt_recent.c +++ b/net/netfilter/xt_recent.c @@ -152,7 +152,8 @@ static void recent_entry_remove(struct recent_table *t, struct recent_entry *e) /* * Drop entries with timestamps older then 'time'. */ -static void recent_entry_reap(struct recent_table *t, unsigned long time) +static void recent_entry_reap(struct recent_table *t, unsigned long time, + struct recent_entry *working, bool update) { struct recent_entry *e; @@ -162,6 +163,12 @@ static void recent_entry_reap(struct recent_table *t, unsigned long time) e = list_entry(t->lru_list.next, struct recent_entry, lru_list); /* + * Do not reap the entry which are going to be updated. + */ + if (e == working && update) + return; + + /* * The last time stamp is the most recent. */ if (time_after(time, e->stamps[e->index-1])) @@ -303,7 +310,8 @@ recent_mt(const struct sk_buff *skb, struct xt_action_param *par) /* info->seconds must be non-zero */ if (info->check_set & XT_RECENT_REAP) - recent_entry_reap(t, time); + recent_entry_reap(t, time, e, + info->check_set & XT_RECENT_UPDATE && ret); } if (info->check_set & XT_RECENT_SET || |