From: Pablo Neira Ayuso <pablo@netfilter.org>
To: netfilter-devel@vger.kernel.org
Cc: davem@davemloft.net, netdev@vger.kernel.org
Subject: [PATCH 07/12] netfilter: ebtables: fix race condition in frame_filter_net_init()
Date: Mon, 9 Oct 2017 18:25:41 +0200 [thread overview]
Message-ID: <1507566346-32553-8-git-send-email-pablo@netfilter.org> (raw)
In-Reply-To: <1507566346-32553-1-git-send-email-pablo@netfilter.org>
From: Artem Savkov <asavkov@redhat.com>
It is possible for ebt_in_hook to be triggered before ebt_table is assigned
resulting in a NULL-pointer dereference. Make sure hooks are
registered as the last step.
Fixes: aee12a0a3727 ("ebtables: remove nf_hook_register usage")
Signed-off-by: Artem Savkov <asavkov@redhat.com>
Signed-off-by: Pablo Neira Ayuso <pablo@netfilter.org>
---
include/linux/netfilter_bridge/ebtables.h | 7 ++++---
net/bridge/netfilter/ebtable_broute.c | 4 ++--
net/bridge/netfilter/ebtable_filter.c | 4 ++--
net/bridge/netfilter/ebtable_nat.c | 4 ++--
net/bridge/netfilter/ebtables.c | 17 +++++++++--------
5 files changed, 19 insertions(+), 17 deletions(-)
diff --git a/include/linux/netfilter_bridge/ebtables.h b/include/linux/netfilter_bridge/ebtables.h
index 2c2a5514b0df..528b24c78308 100644
--- a/include/linux/netfilter_bridge/ebtables.h
+++ b/include/linux/netfilter_bridge/ebtables.h
@@ -108,9 +108,10 @@ struct ebt_table {
#define EBT_ALIGN(s) (((s) + (__alignof__(struct _xt_align)-1)) & \
~(__alignof__(struct _xt_align)-1))
-extern struct ebt_table *ebt_register_table(struct net *net,
- const struct ebt_table *table,
- const struct nf_hook_ops *);
+extern int ebt_register_table(struct net *net,
+ const struct ebt_table *table,
+ const struct nf_hook_ops *ops,
+ struct ebt_table **res);
extern void ebt_unregister_table(struct net *net, struct ebt_table *table,
const struct nf_hook_ops *);
extern unsigned int ebt_do_table(struct sk_buff *skb,
diff --git a/net/bridge/netfilter/ebtable_broute.c b/net/bridge/netfilter/ebtable_broute.c
index 2585b100ebbb..276b60262981 100644
--- a/net/bridge/netfilter/ebtable_broute.c
+++ b/net/bridge/netfilter/ebtable_broute.c
@@ -65,8 +65,8 @@ static int ebt_broute(struct sk_buff *skb)
static int __net_init broute_net_init(struct net *net)
{
- net->xt.broute_table = ebt_register_table(net, &broute_table, NULL);
- return PTR_ERR_OR_ZERO(net->xt.broute_table);
+ return ebt_register_table(net, &broute_table, NULL,
+ &net->xt.broute_table);
}
static void __net_exit broute_net_exit(struct net *net)
diff --git a/net/bridge/netfilter/ebtable_filter.c b/net/bridge/netfilter/ebtable_filter.c
index 45a00dbdbcad..c41da5fac84f 100644
--- a/net/bridge/netfilter/ebtable_filter.c
+++ b/net/bridge/netfilter/ebtable_filter.c
@@ -93,8 +93,8 @@ static const struct nf_hook_ops ebt_ops_filter[] = {
static int __net_init frame_filter_net_init(struct net *net)
{
- net->xt.frame_filter = ebt_register_table(net, &frame_filter, ebt_ops_filter);
- return PTR_ERR_OR_ZERO(net->xt.frame_filter);
+ return ebt_register_table(net, &frame_filter, ebt_ops_filter,
+ &net->xt.frame_filter);
}
static void __net_exit frame_filter_net_exit(struct net *net)
diff --git a/net/bridge/netfilter/ebtable_nat.c b/net/bridge/netfilter/ebtable_nat.c
index 57cd5bb154e7..08df7406ecb3 100644
--- a/net/bridge/netfilter/ebtable_nat.c
+++ b/net/bridge/netfilter/ebtable_nat.c
@@ -93,8 +93,8 @@ static const struct nf_hook_ops ebt_ops_nat[] = {
static int __net_init frame_nat_net_init(struct net *net)
{
- net->xt.frame_nat = ebt_register_table(net, &frame_nat, ebt_ops_nat);
- return PTR_ERR_OR_ZERO(net->xt.frame_nat);
+ return ebt_register_table(net, &frame_nat, ebt_ops_nat,
+ &net->xt.frame_nat);
}
static void __net_exit frame_nat_net_exit(struct net *net)
diff --git a/net/bridge/netfilter/ebtables.c b/net/bridge/netfilter/ebtables.c
index 83951f978445..3b3dcf719e07 100644
--- a/net/bridge/netfilter/ebtables.c
+++ b/net/bridge/netfilter/ebtables.c
@@ -1169,9 +1169,8 @@ static void __ebt_unregister_table(struct net *net, struct ebt_table *table)
kfree(table);
}
-struct ebt_table *
-ebt_register_table(struct net *net, const struct ebt_table *input_table,
- const struct nf_hook_ops *ops)
+int ebt_register_table(struct net *net, const struct ebt_table *input_table,
+ const struct nf_hook_ops *ops, struct ebt_table **res)
{
struct ebt_table_info *newinfo;
struct ebt_table *t, *table;
@@ -1183,7 +1182,7 @@ ebt_register_table(struct net *net, const struct ebt_table *input_table,
repl->entries == NULL || repl->entries_size == 0 ||
repl->counters != NULL || input_table->private != NULL) {
BUGPRINT("Bad table data for ebt_register_table!!!\n");
- return ERR_PTR(-EINVAL);
+ return -EINVAL;
}
/* Don't add one table to multiple lists. */
@@ -1252,16 +1251,18 @@ ebt_register_table(struct net *net, const struct ebt_table *input_table,
list_add(&table->list, &net->xt.tables[NFPROTO_BRIDGE]);
mutex_unlock(&ebt_mutex);
+ WRITE_ONCE(*res, table);
+
if (!ops)
- return table;
+ return 0;
ret = nf_register_net_hooks(net, ops, hweight32(table->valid_hooks));
if (ret) {
__ebt_unregister_table(net, table);
- return ERR_PTR(ret);
+ *res = NULL;
}
- return table;
+ return ret;
free_unlock:
mutex_unlock(&ebt_mutex);
free_chainstack:
@@ -1276,7 +1277,7 @@ ebt_register_table(struct net *net, const struct ebt_table *input_table,
free_table:
kfree(table);
out:
- return ERR_PTR(ret);
+ return ret;
}
void ebt_unregister_table(struct net *net, struct ebt_table *table,
--
2.1.4
next prev parent reply other threads:[~2017-10-09 16:25 UTC|newest]
Thread overview: 14+ messages / expand[flat|nested] mbox.gz Atom feed top
2017-10-09 16:25 [PATCH 00/12] Netfilter/IPVS fixes for net Pablo Neira Ayuso
2017-10-09 16:25 ` [PATCH 01/12] netfilter: ipvs: full-functionality option for ECN encapsulation in tunnel Pablo Neira Ayuso
2017-10-09 16:25 ` [PATCH 02/12] netfilter: xt_socket: Restore mark from full sockets only Pablo Neira Ayuso
2017-10-09 16:25 ` [PATCH 03/12] netfilter: ipset: Fix adding an IPv4 range containing more than 2^31 addresses Pablo Neira Ayuso
2017-10-09 16:25 ` [PATCH 04/12] netfilter: ipset: pernet ops must be unregistered last Pablo Neira Ayuso
2017-10-09 16:25 ` [PATCH 05/12] netfilter: ipset: Fix race between dump and swap Pablo Neira Ayuso
2017-10-09 16:25 ` [PATCH 06/12] netfilter: nf_tables: fix update chain error Pablo Neira Ayuso
2017-10-09 16:25 ` Pablo Neira Ayuso [this message]
2017-10-09 16:25 ` [PATCH 08/12] netfilter: nf_tables: Release memory obtained by kasprintf Pablo Neira Ayuso
2017-10-09 16:25 ` [PATCH 09/12] netfilter: nf_tables: do not dump chain counters if not enabled Pablo Neira Ayuso
2017-10-09 16:25 ` [PATCH 10/12] netfilter: x_tables: avoid stack-out-of-bounds read in xt_copy_counters_from_user Pablo Neira Ayuso
2017-10-09 16:25 ` [PATCH 11/12] netfilter: SYNPROXY: skip non-tcp packet in {ipv4, ipv6}_synproxy_hook Pablo Neira Ayuso
2017-10-09 16:25 ` [PATCH 12/12] netfilter: xt_bpf: Fix XT_BPF_MODE_FD_PINNED mode of 'xt_bpf_info_v1' Pablo Neira Ayuso
2017-10-09 17:40 ` [PATCH 00/12] Netfilter/IPVS fixes for net David Miller
Reply instructions:
You may reply publicly to this message via plain-text email
using any one of the following methods:
* Save the following mbox file, import it into your mail client,
and reply-to-all from there: mbox
Avoid top-posting and favor interleaved quoting:
https://en.wikipedia.org/wiki/Posting_style#Interleaved_style
* Reply using the --to, --cc, and --in-reply-to
switches of git-send-email(1):
git send-email \
--in-reply-to=1507566346-32553-8-git-send-email-pablo@netfilter.org \
--to=pablo@netfilter.org \
--cc=davem@davemloft.net \
--cc=netdev@vger.kernel.org \
--cc=netfilter-devel@vger.kernel.org \
/path/to/YOUR_REPLY
https://kernel.org/pub/software/scm/git/docs/git-send-email.html
* If your mail client supports setting the In-Reply-To header
via mailto: links, try the mailto: link
Be sure your reply has a Subject: header at the top and a blank line
before the message body.
This is a public inbox, see mirroring instructions
for how to clone and mirror all data and code used for this inbox;
as well as URLs for NNTP newsgroup(s).