From: Florian Westphal <fw@strlen.de>
To: netfilter-devel@vger.kernel.org
Cc: netdev@vger.kernel.org, syzkaller-bugs@googlegroups.com,
Florian Westphal <fw@strlen.de>,
syzbot+91bdd8eece0f6629ec8b@syzkaller.appspotmail.com
Subject: [PATCH nf] netfilter: arp_tables: init netns pointer in xt_tgdtor_param struct
Date: Sat, 11 Jan 2020 23:19:53 +0100 [thread overview]
Message-ID: <20200111221953.17759-1-fw@strlen.de> (raw)
In-Reply-To: <000000000000af1c5b059be111e5@google.com>
An earlier commit (1b789577f655060d98d20e,
"netfilter: arp_tables: init netns pointer in xt_tgchk_param struct"
fixed missing net initialization for arptables, but turns out it was
incomplete. We can get a very similar struct net NULL deref during
error unwinding:
general protection fault: 0000 [#1] PREEMPT SMP KASAN
RIP: 0010:xt_rateest_put+0xa1/0x440 net/netfilter/xt_RATEEST.c:77
xt_rateest_tg_destroy+0x72/0xa0 net/netfilter/xt_RATEEST.c:175
cleanup_entry net/ipv4/netfilter/arp_tables.c:509 [inline]
translate_table+0x11f4/0x1d80 net/ipv4/netfilter/arp_tables.c:587
do_replace net/ipv4/netfilter/arp_tables.c:981 [inline]
do_arpt_set_ctl+0x317/0x650 net/ipv4/netfilter/arp_tables.c:1461
Also init the netns pointer in xt_tgdtor_param struct.
Fixes: add67461240c1d ("netfilter: add struct net * to target parameters")
Reported-by: syzbot+91bdd8eece0f6629ec8b@syzkaller.appspotmail.com
Signed-off-by: Florian Westphal <fw@strlen.de>
---
net/ipv4/netfilter/arp_tables.c | 19 ++++++++++---------
1 file changed, 10 insertions(+), 9 deletions(-)
diff --git a/net/ipv4/netfilter/arp_tables.c b/net/ipv4/netfilter/arp_tables.c
index 069f72edb264..f1f78a742b36 100644
--- a/net/ipv4/netfilter/arp_tables.c
+++ b/net/ipv4/netfilter/arp_tables.c
@@ -496,12 +496,13 @@ static inline int check_entry_size_and_hooks(struct arpt_entry *e,
return 0;
}
-static inline void cleanup_entry(struct arpt_entry *e)
+static void cleanup_entry(struct arpt_entry *e, struct net *net)
{
struct xt_tgdtor_param par;
struct xt_entry_target *t;
t = arpt_get_target(e);
+ par.net = net;
par.target = t->u.kernel.target;
par.targinfo = t->data;
par.family = NFPROTO_ARP;
@@ -584,7 +585,7 @@ static int translate_table(struct net *net,
xt_entry_foreach(iter, entry0, newinfo->size) {
if (i-- == 0)
break;
- cleanup_entry(iter);
+ cleanup_entry(iter, net);
}
return ret;
}
@@ -927,7 +928,7 @@ static int __do_replace(struct net *net, const char *name,
/* Decrease module usage counts and free resource */
loc_cpu_old_entry = oldinfo->entries;
xt_entry_foreach(iter, loc_cpu_old_entry, oldinfo->size)
- cleanup_entry(iter);
+ cleanup_entry(iter, net);
xt_free_table_info(oldinfo);
if (copy_to_user(counters_ptr, counters,
@@ -990,7 +991,7 @@ static int do_replace(struct net *net, const void __user *user,
free_newinfo_untrans:
xt_entry_foreach(iter, loc_cpu_entry, newinfo->size)
- cleanup_entry(iter);
+ cleanup_entry(iter, net);
free_newinfo:
xt_free_table_info(newinfo);
return ret;
@@ -1287,7 +1288,7 @@ static int compat_do_replace(struct net *net, void __user *user,
free_newinfo_untrans:
xt_entry_foreach(iter, loc_cpu_entry, newinfo->size)
- cleanup_entry(iter);
+ cleanup_entry(iter, net);
free_newinfo:
xt_free_table_info(newinfo);
return ret;
@@ -1514,7 +1515,7 @@ static int do_arpt_get_ctl(struct sock *sk, int cmd, void __user *user, int *len
return ret;
}
-static void __arpt_unregister_table(struct xt_table *table)
+static void __arpt_unregister_table(struct net *net, struct xt_table *table)
{
struct xt_table_info *private;
void *loc_cpu_entry;
@@ -1526,7 +1527,7 @@ static void __arpt_unregister_table(struct xt_table *table)
/* Decrease module usage counts and free resources */
loc_cpu_entry = private->entries;
xt_entry_foreach(iter, loc_cpu_entry, private->size)
- cleanup_entry(iter);
+ cleanup_entry(iter, net);
if (private->number > private->initial_entries)
module_put(table_owner);
xt_free_table_info(private);
@@ -1566,7 +1567,7 @@ int arpt_register_table(struct net *net,
ret = nf_register_net_hooks(net, ops, hweight32(table->valid_hooks));
if (ret != 0) {
- __arpt_unregister_table(new_table);
+ __arpt_unregister_table(net, new_table);
*res = NULL;
}
@@ -1581,7 +1582,7 @@ void arpt_unregister_table(struct net *net, struct xt_table *table,
const struct nf_hook_ops *ops)
{
nf_unregister_net_hooks(net, ops, hweight32(table->valid_hooks));
- __arpt_unregister_table(table);
+ __arpt_unregister_table(net, table);
}
/* The built-in targets: standard (NULL) and error. */
--
2.24.1
next prev parent reply other threads:[~2020-01-11 22:35 UTC|newest]
Thread overview: 7+ messages / expand[flat|nested] mbox.gz Atom feed top
2020-01-11 18:04 general protection fault in xt_rateest_put syzbot
2020-01-11 20:05 ` Cong Wang
2020-01-11 21:13 ` Florian Westphal
2020-01-11 21:34 ` Cong Wang
2020-01-11 22:19 ` Florian Westphal [this message]
2020-01-13 17:51 ` [PATCH nf] netfilter: arp_tables: init netns pointer in xt_tgdtor_param struct Pablo Neira Ayuso
2020-01-12 20:13 ` general protection fault in xt_rateest_put syzbot
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