Hi Pablo,
Please review the next patch and consider applying it in the nf branch:
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.
Reported by Reindl Harald.
Signed-off-by: Jozsef Kadlecsik <kadlec@xxxxxxxxxxxxx>
---
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 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;
@@ -161,6 +162,12 @@ 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.
*/
@@ -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 ||
--
2.20.1
Best regards,
Jozsef
-
E-mail : kadlec@xxxxxxxxxxxxxxxxx, kadlecsik.jozsef@xxxxxxxxx
PGP key : https://wigner.hu/~kadlec/pgp_public_key.txt
Address : Wigner Research Centre for Physics
H-1525 Budapest 114, POB. 49, Hungary
