From: David Howells dhowells@redhat.com
[ Upstream commit 9ebeddef58c41bd700419cdcece24cf64ce32276 ]
The rxrpc_peer record needs to hold a reference on the rxrpc_local record it points as the peer is used as a base to access information in the rxrpc_local record.
This can cause problems in __rxrpc_put_peer(), where we need the network namespace pointer, and in rxrpc_send_keepalive(), where we need to access the UDP socket, leading to symptoms like:
BUG: KASAN: use-after-free in __rxrpc_put_peer net/rxrpc/peer_object.c:411 [inline] BUG: KASAN: use-after-free in rxrpc_put_peer+0x685/0x6a0 net/rxrpc/peer_object.c:435 Read of size 8 at addr ffff888097ec0058 by task syz-executor823/24216
Fix this by taking a ref on the local record for the peer record.
Fixes: ace45bec6d77 ("rxrpc: Fix firewall route keepalive") Fixes: 2baec2c3f854 ("rxrpc: Support network namespacing") Reported-by: syzbot+b9be979c55f2bea8ed30@syzkaller.appspotmail.com Signed-off-by: David Howells dhowells@redhat.com Signed-off-by: Sasha Levin sashal@kernel.org --- net/rxrpc/peer_object.c | 5 +++-- 1 file changed, 3 insertions(+), 2 deletions(-)
diff --git a/net/rxrpc/peer_object.c b/net/rxrpc/peer_object.c index b700b7ecaa3d8..64830d8c1fdb5 100644 --- a/net/rxrpc/peer_object.c +++ b/net/rxrpc/peer_object.c @@ -216,7 +216,7 @@ struct rxrpc_peer *rxrpc_alloc_peer(struct rxrpc_local *local, gfp_t gfp) peer = kzalloc(sizeof(struct rxrpc_peer), gfp); if (peer) { atomic_set(&peer->usage, 1); - peer->local = local; + peer->local = rxrpc_get_local(local); INIT_HLIST_HEAD(&peer->error_targets); peer->service_conns = RB_ROOT; seqlock_init(&peer->service_conn_lock); @@ -307,7 +307,6 @@ void rxrpc_new_incoming_peer(struct rxrpc_sock *rx, struct rxrpc_local *local, unsigned long hash_key;
hash_key = rxrpc_peer_hash_key(local, &peer->srx); - peer->local = local; rxrpc_init_peer(rx, peer, hash_key);
spin_lock(&rxnet->peer_hash_lock); @@ -417,6 +416,7 @@ static void __rxrpc_put_peer(struct rxrpc_peer *peer) list_del_init(&peer->keepalive_link); spin_unlock_bh(&rxnet->peer_hash_lock);
+ rxrpc_put_local(peer->local); kfree_rcu(peer, rcu); }
@@ -453,6 +453,7 @@ void rxrpc_put_peer_locked(struct rxrpc_peer *peer) if (n == 0) { hash_del_rcu(&peer->hash_link); list_del_init(&peer->keepalive_link); + rxrpc_put_local(peer->local); kfree_rcu(peer, rcu); } }