Re: [PATCH net 1/4] netfilter: xt_recent: Fix attempt to update deleted entry
From: Reindl Harald <hidden>
Date: 2021-02-05 11:58:17
Also in:
netfilter-devel
thank you for adressing that issue - maybe GRO can be enabled and wasn't involved at all "Reap only entries which won't be updated" sounds for me like the could be some optimization: i mean when you first update and then check what can be reaped the recently updated entry would not match to begin with Am 05.02.21 um 01:17 schrieb Pablo Neira Ayuso:
quoted hunk ↗ jump to hunk
From: Jozsef Kadlecsik <redacted> 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 <redacted> Fixes: 0079c5aee348 ("netfilter: xt_recent: add an entry reaper") Signed-off-by: Jozsef Kadlecsik <redacted> Signed-off-by: Pablo Neira Ayuso <pablo@netfilter.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 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 ||