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Message-ID: <20231204190044.450107-5-dima@arista.com>
Date: Mon, 4 Dec 2023 19:00:43 +0000
From: Dmitry Safonov <dima@...sta.com>
To: David Ahern <dsahern@...nel.org>,
Eric Dumazet <edumazet@...gle.com>,
Paolo Abeni <pabeni@...hat.com>,
Jakub Kicinski <kuba@...nel.org>,
"David S. Miller" <davem@...emloft.net>
Cc: linux-kernel@...r.kernel.org,
Dmitry Safonov <dima@...sta.com>,
Dmitry Safonov <0x7f454c46@...il.com>,
Francesco Ruggeri <fruggeri05@...il.com>,
Salam Noureddine <noureddine@...sta.com>,
Simon Horman <horms@...nel.org>,
netdev@...r.kernel.org
Subject: [PATCH v5 4/5] net/tcp: Don't add key with non-matching VRF on connected sockets
If the connection was established, don't allow adding TCP-AO keys that
don't match the peer. Currently, there are checks for ip-address
matching, but L3 index check is missing. Add it to restrict userspace
shooting itself somewhere.
Yet, nothing restricts the CAP_NET_RAW user from trying to shoot
themselves by performing setsockopt(SO_BINDTODEVICE) or
setsockopt(SO_BINDTOIFINDEX) over an established TCP-AO connection.
So, this is just "minimum effort" to potentially save someone's
debugging time, rather than a full restriction on doing weird things.
Fixes: 248411b8cb89 ("net/tcp: Wire up l3index to TCP-AO")
Signed-off-by: Dmitry Safonov <dima@...sta.com>
Reviewed-by: Eric Dumazet <edumazet@...gle.com>
---
net/ipv4/tcp_ao.c | 9 +++++++++
1 file changed, 9 insertions(+)
diff --git a/net/ipv4/tcp_ao.c b/net/ipv4/tcp_ao.c
index c8be1d526eac..18dacfef7a07 100644
--- a/net/ipv4/tcp_ao.c
+++ b/net/ipv4/tcp_ao.c
@@ -1608,6 +1608,15 @@ static int tcp_ao_add_cmd(struct sock *sk, unsigned short int family,
if (!dev || !l3index)
return -EINVAL;
+ if (!bound_dev_if || bound_dev_if != cmd.ifindex) {
+ /* tcp_ao_established_key() doesn't expect having
+ * non peer-matching key on an established TCP-AO
+ * connection.
+ */
+ if (!((1 << sk->sk_state) & (TCPF_LISTEN | TCPF_CLOSE)))
+ return -EINVAL;
+ }
+
/* It's still possible to bind after adding keys or even
* re-bind to a different dev (with CAP_NET_RAW).
* So, no reason to return error here, rather try to be
--
2.43.0
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