From: Pablo Neira Ayuso <pablo@netfilter.org>
To: netfilter-devel@vger.kernel.org
Cc: davem@davemloft.net, netdev@vger.kernel.org
Subject: [PATCH 1/6] netfilter: ipset: fix suspicious RCU usage in find_set_and_id
Date: Fri, 31 Jan 2020 20:24:23 +0100 [thread overview]
Message-ID: <20200131192428.167274-2-pablo@netfilter.org> (raw)
In-Reply-To: <20200131192428.167274-1-pablo@netfilter.org>
From: Kadlecsik József <kadlec@blackhole.kfki.hu>
find_set_and_id() is called when the NFNL_SUBSYS_IPSET mutex is held.
However, in the error path there can be a follow-up recvmsg() without
the mutex held. Use the start() function of struct netlink_dump_control
instead of dump() to verify and report if the specified set does not
exist.
Thanks to Pablo Neira Ayuso for helping me to understand the subleties
of the netlink protocol.
Reported-by: syzbot+fc69d7cb21258ab4ae4d@syzkaller.appspotmail.com
Signed-off-by: Jozsef Kadlecsik <kadlec@netfilter.org>
Signed-off-by: Pablo Neira Ayuso <pablo@netfilter.org>
---
net/netfilter/ipset/ip_set_core.c | 41 ++++++++++++++++++++-------------------
1 file changed, 21 insertions(+), 20 deletions(-)
diff --git a/net/netfilter/ipset/ip_set_core.c b/net/netfilter/ipset/ip_set_core.c
index cf895bc80871..69c107f9ba8d 100644
--- a/net/netfilter/ipset/ip_set_core.c
+++ b/net/netfilter/ipset/ip_set_core.c
@@ -1483,31 +1483,34 @@ ip_set_dump_policy[IPSET_ATTR_CMD_MAX + 1] = {
};
static int
-dump_init(struct netlink_callback *cb, struct ip_set_net *inst)
+ip_set_dump_start(struct netlink_callback *cb)
{
struct nlmsghdr *nlh = nlmsg_hdr(cb->skb);
int min_len = nlmsg_total_size(sizeof(struct nfgenmsg));
struct nlattr *cda[IPSET_ATTR_CMD_MAX + 1];
struct nlattr *attr = (void *)nlh + min_len;
+ struct sk_buff *skb = cb->skb;
+ struct ip_set_net *inst = ip_set_pernet(sock_net(skb->sk));
u32 dump_type;
- ip_set_id_t index;
int ret;
ret = nla_parse(cda, IPSET_ATTR_CMD_MAX, attr,
nlh->nlmsg_len - min_len,
ip_set_dump_policy, NULL);
if (ret)
- return ret;
+ goto error;
cb->args[IPSET_CB_PROTO] = nla_get_u8(cda[IPSET_ATTR_PROTOCOL]);
if (cda[IPSET_ATTR_SETNAME]) {
+ ip_set_id_t index;
struct ip_set *set;
set = find_set_and_id(inst, nla_data(cda[IPSET_ATTR_SETNAME]),
&index);
- if (!set)
- return -ENOENT;
-
+ if (!set) {
+ ret = -ENOENT;
+ goto error;
+ }
dump_type = DUMP_ONE;
cb->args[IPSET_CB_INDEX] = index;
} else {
@@ -1523,10 +1526,17 @@ dump_init(struct netlink_callback *cb, struct ip_set_net *inst)
cb->args[IPSET_CB_DUMP] = dump_type;
return 0;
+
+error:
+ /* We have to create and send the error message manually :-( */
+ if (nlh->nlmsg_flags & NLM_F_ACK) {
+ netlink_ack(cb->skb, nlh, ret, NULL);
+ }
+ return ret;
}
static int
-ip_set_dump_start(struct sk_buff *skb, struct netlink_callback *cb)
+ip_set_dump_do(struct sk_buff *skb, struct netlink_callback *cb)
{
ip_set_id_t index = IPSET_INVALID_ID, max;
struct ip_set *set = NULL;
@@ -1537,18 +1547,8 @@ ip_set_dump_start(struct sk_buff *skb, struct netlink_callback *cb)
bool is_destroyed;
int ret = 0;
- if (!cb->args[IPSET_CB_DUMP]) {
- ret = dump_init(cb, inst);
- if (ret < 0) {
- nlh = nlmsg_hdr(cb->skb);
- /* We have to create and send the error message
- * manually :-(
- */
- if (nlh->nlmsg_flags & NLM_F_ACK)
- netlink_ack(cb->skb, nlh, ret, NULL);
- return ret;
- }
- }
+ if (!cb->args[IPSET_CB_DUMP])
+ return -EINVAL;
if (cb->args[IPSET_CB_INDEX] >= inst->ip_set_max)
goto out;
@@ -1684,7 +1684,8 @@ static int ip_set_dump(struct net *net, struct sock *ctnl, struct sk_buff *skb,
{
struct netlink_dump_control c = {
- .dump = ip_set_dump_start,
+ .start = ip_set_dump_start,
+ .dump = ip_set_dump_do,
.done = ip_set_dump_done,
};
return netlink_dump_start(ctnl, skb, nlh, &c);
--
2.11.0
next prev parent reply other threads:[~2020-01-31 19:24 UTC|newest]
Thread overview: 12+ messages / expand[flat|nested] mbox.gz Atom feed top
2020-01-31 19:24 [PATCH 0/6] Netfilter fixes for net Pablo Neira Ayuso
2020-01-31 19:24 ` Pablo Neira Ayuso [this message]
2020-02-01 20:57 ` [PATCH 1/6] netfilter: ipset: fix suspicious RCU usage in find_set_and_id Jakub Kicinski
2020-02-01 21:05 ` Jakub Kicinski
2020-02-01 21:11 ` Jozsef Kadlecsik
2020-02-02 4:21 ` Jakub Kicinski
2020-01-31 19:24 ` [PATCH 2/6] netfilter: Use kvcalloc Pablo Neira Ayuso
2020-01-31 19:24 ` [PATCH 3/6] netfilter: flowtable: Fix hardware flush order on nf_flow_table_cleanup Pablo Neira Ayuso
2020-01-31 19:24 ` [PATCH 4/6] netfilter: flowtable: Fix missing flush hardware on table free Pablo Neira Ayuso
2020-01-31 19:24 ` [PATCH 5/6] netfilter: flowtable: Fix setting forgotten NF_FLOW_HW_DEAD flag Pablo Neira Ayuso
2020-01-31 19:24 ` [PATCH 6/6] netfilter: nf_flowtable: fix documentation Pablo Neira Ayuso
2020-02-01 20:59 ` [PATCH 0/6] Netfilter fixes for net Jakub Kicinski
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