[PATCH 4.18 36/53] bpf: sockmap only allow ESTABLISHED sock state

Greg Kroah-Hartman
2018-10-19T02:00:06Z

From: John Fastabend <john.fastabend@gmail.com>

[ Upstream commit 5607fff303636d48b88414c6be353d9fed700af2 ]

After this patch we only allow socks that are in ESTABLISHED state or
are being added via a sock_ops event that is transitioning into an
ESTABLISHED state. By allowing sock_ops events we allow users to
manage sockmaps directly from sock ops programs. The two supported
sock_ops ops are BPF_SOCK_OPS_PASSIVE_ESTABLISHED_CB and
BPF_SOCK_OPS_ACTIVE_ESTABLISHED_CB.

Similar to TLS ULP this ensures sk_user_data is correct.

Reported-by: Eric Dumazet <edumazet@google.com>
Fixes: 1aa12bdf1bfb ("bpf: sockmap, add sock close() hook to remove socks")
Signed-off-by: John Fastabend <john.fastabend@gmail.com>
Acked-by: Yonghong Song <yhs@fb.com>
Signed-off-by: Daniel Borkmann <daniel@iogearbox.net>
Signed-off-by: Sasha Levin <alexander.levin@microsoft.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
---
kernel/bpf/sockmap.c | 31 ++++++++++++++++++++++++++++++-
1 file changed, 30 insertions(+), 1 deletion(-)

--- a/kernel/bpf/sockmap.c
+++ b/kernel/bpf/sockmap.c
@@ -2100,8 +2100,12 @@ static int sock_map_update_elem(struct b
return -EINVAL;
}

+ /* ULPs are currently supported only for TCP sockets in ESTABLISHED
+ * state.
+ */
if (skops.sk->sk_type != SOCK_STREAM ||
- skops.sk->sk_protocol != IPPROTO_TCP) {
+ skops.sk->sk_protocol != IPPROTO_TCP ||
+ skops.sk->sk_state != TCP_ESTABLISHED) {
fput(socket->file);
return -EOPNOTSUPP;
}
@@ -2456,6 +2460,16 @@ static int sock_hash_update_elem(struct
return -EINVAL;
}

+ /* ULPs are currently supported only for TCP sockets in ESTABLISHED
+ * state.
+ */
+ if (skops.sk->sk_type != SOCK_STREAM ||
+ skops.sk->sk_protocol != IPPROTO_TCP ||
+ skops.sk->sk_state != TCP_ESTABLISHED) {
+ fput(socket->file);
+ return -EOPNOTSUPP;
+ }
+
lock_sock(skops.sk);
preempt_disable();
rcu_read_lock();
@@ -2544,10 +2558,22 @@ const struct bpf_map_ops sock_hash_ops =
.map_release_uref = sock_map_release,
};

+static bool bpf_is_valid_sock_op(struct bpf_sock_ops_kern *ops)
+{
+ return ops->op == BPF_SOCK_OPS_PASSIVE_ESTABLISHED_CB ||
+ ops->op == BPF_SOCK_OPS_ACTIVE_ESTABLISHED_CB;
+}
BPF_CALL_4(bpf_sock_map_update, struct bpf_sock_ops_kern *, bpf_sock,
struct bpf_map *, map, void *, key, u64, flags)
{
WARN_ON_ONCE(!rcu_read_lock_held());
+
+ /* ULPs are currently supported only for TCP sockets in ESTABLISHED
+ * state. This checks that the sock ops triggering the update is
+ * one indicating we are (or will be soon) in an ESTABLISHED state.
+ */
+ if (!bpf_is_valid_sock_op(bpf_sock))
+ return -EOPNOTSUPP;
return sock_map_ctx_update_elem(bpf_sock, map, key, flags);
}

@@ -2566,6 +2592,9 @@ BPF_CALL_4(bpf_sock_hash_update, struct
struct bpf_map *, map, void *, key, u64, flags)
{
WARN_ON_ONCE(!rcu_read_lock_held());
+
+ if (!bpf_is_valid_sock_op(bpf_sock))
+ return -EOPNOTSUPP;
return sock_hash_ctx_update_elem(bpf_sock, map, key, flags);
}