[PATCH net v6 09/10] ip6mr: Lock RCU before ip6mr_get_table() call in ip6mr_rtm_getroute()
From: Stefan Wiehler
Date: Thu Oct 17 2024 - 13:45:10 EST
When IPV6_MROUTE_MULTIPLE_TABLES is enabled, multicast routing tables
must be read under RCU or RTNL lock.
Fixes: d1db275dd3f6 ("ipv6: ip6mr: support multiple tables")
Signed-off-by: Stefan Wiehler <stefan.wiehler@xxxxxxxxx>
---
net/ipv6/ip6mr.c | 10 +++++++---
1 file changed, 7 insertions(+), 3 deletions(-)
diff --git a/net/ipv6/ip6mr.c b/net/ipv6/ip6mr.c
index b169b27de7e1..39aac81a30f1 100644
--- a/net/ipv6/ip6mr.c
+++ b/net/ipv6/ip6mr.c
@@ -2633,27 +2633,31 @@ static int ip6mr_rtm_getroute(struct sk_buff *in_skb, struct nlmsghdr *nlh,
grp = nla_get_in6_addr(tb[RTA_DST]);
tableid = tb[RTA_TABLE] ? nla_get_u32(tb[RTA_TABLE]) : 0;
+ rcu_read_lock();
mrt = ip6mr_get_table(net, tableid ?: RT_TABLE_DEFAULT);
if (!mrt) {
+ rcu_read_unlock();
NL_SET_ERR_MSG_MOD(extack, "MR table does not exist");
return -ENOENT;
}
/* entries are added/deleted only under RTNL */
- rcu_read_lock();
cache = ip6mr_cache_find(mrt, &src, &grp);
- rcu_read_unlock();
if (!cache) {
+ rcu_read_unlock();
NL_SET_ERR_MSG_MOD(extack, "MR cache entry not found");
return -ENOENT;
}
skb = nlmsg_new(mr6_msgsize(false, mrt->maxvif), GFP_KERNEL);
- if (!skb)
+ if (!skb) {
+ rcu_read_unlock();
return -ENOBUFS;
+ }
err = ip6mr_fill_mroute(mrt, skb, NETLINK_CB(in_skb).portid,
nlh->nlmsg_seq, cache, RTM_NEWROUTE, 0);
+ rcu_read_unlock();
if (err < 0) {
kfree_skb(skb);
return err;
--
2.42.0