From 99ba2b5aba24e022683a7db63204f9e306fe7ab9 Mon Sep 17 00:00:00 2001 From: John Fastabend Date: Thu, 5 Jul 2018 08:50:04 -0700 Subject: bpf: sockhash, disallow bpf_tcp_close and update in parallel After latest lock updates there is no longer anything preventing a close and recvmsg call running in parallel. Additionally, we can race update with close if we close a socket and simultaneously update if via the BPF userspace API (note the cgroup ops are already run with sock_lock held). To resolve this take sock_lock in close and update paths. Reported-by: syzbot+b680e42077a0d7c9a0c4@syzkaller.appspotmail.com Fixes: e9db4ef6bf4c ("bpf: sockhash fix omitted bucket lock in sock_close") Signed-off-by: John Fastabend Signed-off-by: Alexei Starovoitov --- kernel/bpf/sockmap.c | 15 +++++++++++++++ kernel/bpf/syscall.c | 4 +++- 2 files changed, 18 insertions(+), 1 deletion(-) (limited to 'kernel/bpf') diff --git a/kernel/bpf/sockmap.c b/kernel/bpf/sockmap.c index 00fb2e328d1b..9c67e96fe336 100644 --- a/kernel/bpf/sockmap.c +++ b/kernel/bpf/sockmap.c @@ -312,10 +312,12 @@ static void bpf_tcp_close(struct sock *sk, long timeout) struct smap_psock *psock; struct sock *osk; + lock_sock(sk); rcu_read_lock(); psock = smap_psock_sk(sk); if (unlikely(!psock)) { rcu_read_unlock(); + release_sock(sk); return sk->sk_prot->close(sk, timeout); } @@ -371,6 +373,7 @@ static void bpf_tcp_close(struct sock *sk, long timeout) e = psock_map_pop(sk, psock); } rcu_read_unlock(); + release_sock(sk); close_fun(sk, timeout); } @@ -2069,7 +2072,13 @@ static int sock_map_update_elem(struct bpf_map *map, return -EOPNOTSUPP; } + lock_sock(skops.sk); + preempt_disable(); + rcu_read_lock(); err = sock_map_ctx_update_elem(&skops, map, key, flags); + rcu_read_unlock(); + preempt_enable(); + release_sock(skops.sk); fput(socket->file); return err; } @@ -2410,7 +2419,13 @@ static int sock_hash_update_elem(struct bpf_map *map, return -EINVAL; } + lock_sock(skops.sk); + preempt_disable(); + rcu_read_lock(); err = sock_hash_ctx_update_elem(&skops, map, key, flags); + rcu_read_unlock(); + preempt_enable(); + release_sock(skops.sk); fput(socket->file); return err; } diff --git a/kernel/bpf/syscall.c b/kernel/bpf/syscall.c index d10ecd78105f..a31a1ba0f8ea 100644 --- a/kernel/bpf/syscall.c +++ b/kernel/bpf/syscall.c @@ -735,7 +735,9 @@ static int map_update_elem(union bpf_attr *attr) if (bpf_map_is_dev_bound(map)) { err = bpf_map_offload_update_elem(map, key, value, attr->flags); goto out; - } else if (map->map_type == BPF_MAP_TYPE_CPUMAP) { + } else if (map->map_type == BPF_MAP_TYPE_CPUMAP || + map->map_type == BPF_MAP_TYPE_SOCKHASH || + map->map_type == BPF_MAP_TYPE_SOCKMAP) { err = map->ops->map_update_elem(map, key, value, attr->flags); goto out; } -- cgit v1.2.3-59-g8ed1b