On Wed, Aug 24, 2022 at 11:37:23AM +0200, Arne Schwabe wrote:
> With delayed data key generation now with deferred auth, NCP and similar
> mechanism the "TLS Error: local/remote TLS keys are out of sync" is shown
> much too frequent and confuses a lot of people.
>
> This also removes the dead code of printing multi not ready keys and
> replace it with an assert.
>
> Factor out printing of error messages into an extra function to make
> the code easier to understand and also to only call into that function
> in the case that a key is not found and avoid the overhead.
Okay, I have to say that this patch confuses me. Might be my limited
understanding of the involved structures, though.
> diff --git a/src/openvpn/ssl.c b/src/openvpn/ssl.c
> index 33e145b3f..6a3473944 100644
> --- a/src/openvpn/ssl.c
> +++ b/src/openvpn/ssl.c
> @@ -3202,11 +3202,61 @@ nohard:
> return (tas == TLS_AUTHENTICATION_FAILED) ? TLSMP_KILL : active;
> }
>
> -/*
> - * Pre and post-process the encryption & decryption buffers in order
> - * to implement a multiplexed TLS channel over the TCP/UDP port.
> +/**
> + * We have not found a matching key to decrypt data channel packet,
> + * try to generate a sensible error message and print it
> */
> +static void
> +print_key_id_not_found_reason(struct tls_multi *multi,
> + const struct link_socket_actual *from, int
> key_id)
> +{
> + struct gc_arena gc = gc_new();
> + const char *source = print_link_socket_actual(from, &gc);
> +
> +
> + for (int i = 0; i < KEY_SCAN_SIZE; ++i)
> + {
> + struct key_state *ks = get_key_scan(multi, i);
> + /*
> + * Our key state has been progressed far enough to be part of an
> valid
> + * session but has not generated keys. Since there can
> + * be multiple valid/semi valid key states with key id 0 (especially
> in
> + * p2p mode when a client reconnects), we still need
> + * to loop through all keys and only remember here that there is at
> + * least one key that is not ready yet*/
> + if (ks->state >= S_INITIAL && key_id < S_GENERATED_KEYS)
Why are you comparing key_id to a state value? Shouldn't you compare
ks->state to S_GENERATED_KEYS and ks->key_id to the key_id?
> + {
> + msg(D_MULTI_DROPPED,
> + "Key %s [%d] not initialized (yet), dropping packet.",
> + source, key_id);
> + gc_free(&gc);
> + return;
> + }
> + if (ks->state >= S_ACTIVE && ks->authenticated == KS_AUTH_FALSE)
While here we do check key_id at all?
> + {
> + msg(D_MULTI_DROPPED,
> + "Key %s [%d] no longer authorized (yet), dropping packet.",
> + source, key_id);
> + gc_free(&gc);
> + return;
> + }
> + }
Regards,
--
Frank Lichtenheld
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