From: Jozsef Kadlecsik kadlec@mail.kfki.hu
[ Upstream commit b1bdde33b72366da20d10770ab7a49fe87b5e190 ]
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 Signed-off-by: Sasha Levin sashal@kernel.org --- net/netfilter/xt_recent.c | 12 ++++++++++-- 1 file changed, 10 insertions(+), 2 deletions(-)
diff --git a/net/netfilter/xt_recent.c b/net/netfilter/xt_recent.c index 79d7ad621a80f..03c8bd854e56a 100644 --- a/net/netfilter/xt_recent.c +++ b/net/netfilter/xt_recent.c @@ -155,7 +155,8 @@ 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;
@@ -164,6 +165,12 @@ 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. */ @@ -306,7 +313,8 @@ 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 ||