5.4-stable review patch. If anyone has any objections, please let me know.
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From: Eric Dumazet edumazet@google.com
[ Upstream commit becbd5850c03ed33b232083dd66c6e38c0c0e569 ]
__neigh_notify() can be called without RTNL or RCU protection.
Use RCU protection to avoid potential UAF.
Fixes: 426b5303eb43 ("[NETNS]: Modify the neighbour table code so it handles multiple network namespaces") Signed-off-by: Eric Dumazet edumazet@google.com Reviewed-by: David Ahern dsahern@kernel.org Reviewed-by: Kuniyuki Iwashima kuniyu@amazon.com Link: https://patch.msgid.link/20250207135841.1948589-4-edumazet@google.com Signed-off-by: Jakub Kicinski kuba@kernel.org Signed-off-by: Sasha Levin sashal@kernel.org --- net/core/neighbour.c | 8 ++++++-- 1 file changed, 6 insertions(+), 2 deletions(-)
diff --git a/net/core/neighbour.c b/net/core/neighbour.c index 3e007cbadb707..7ef3630ea20d7 100644 --- a/net/core/neighbour.c +++ b/net/core/neighbour.c @@ -3364,10 +3364,12 @@ static const struct seq_operations neigh_stat_seq_ops = { static void __neigh_notify(struct neighbour *n, int type, int flags, u32 pid) { - struct net *net = dev_net(n->dev); struct sk_buff *skb; int err = -ENOBUFS; + struct net *net;
+ rcu_read_lock(); + net = dev_net_rcu(n->dev); skb = nlmsg_new(neigh_nlmsg_size(), GFP_ATOMIC); if (skb == NULL) goto errout; @@ -3380,9 +3382,11 @@ static void __neigh_notify(struct neighbour *n, int type, int flags, goto errout; } rtnl_notify(skb, net, 0, RTNLGRP_NEIGH, NULL, GFP_ATOMIC); - return; + goto out; errout: rtnl_set_sk_err(net, RTNLGRP_NEIGH, err); +out: + rcu_read_unlock(); }
void neigh_app_ns(struct neighbour *n)