Attention is currently required from: plaisthos.
Hello plaisthos,
I'd like you to reexamine a change. Please visit
http://gerrit.openvpn.net/c/openvpn/+/1759?usp=email
to look at the new patch set (#18).
Change subject: oob: Send tls-crypt-v2 SERVER_PROBE from the client
......................................................................
oob: Send tls-crypt-v2 SERVER_PROBE from the client
When tls-crypt-v2 is configured, send the probe as P_CONTROL_OOB_WKC_V1
with the wrapped client key (WKc) appended, so the server can recover
the per-client key and unwrap it. Without tls-crypt-v2 the probe stays a
plain P_CONTROL_OOB_V1, unchanged.
- drop the "skip probing under tls-crypt-v2" bail-out
- make the WKc available on the probe's wrap context (mirroring
init_instance()), so tls_wrap_control() appends it
- choose the opcode (P_CONTROL_OOB_WKC_V1 vs P_CONTROL_OOB_V1) and
report "tls-crypt-v2" in the wrapping log line
Change-Id: I5cc100dd7dc810d7d1e6f29bb57584905fbcf4a0
Signed-off-by: Lev Stipakov <[email protected]>
---
M doc/man-sections/client-options.rst
M src/openvpn/oob_client.c
2 files changed, 28 insertions(+), 30 deletions(-)
git pull ssh://gerrit.openvpn.net:29418/openvpn refs/changes/59/1759/18
diff --git a/doc/man-sections/client-options.rst
b/doc/man-sections/client-options.rst
index 3958ef9..8b80dbd1 100644
--- a/doc/man-sections/client-options.rst
+++ b/doc/man-sections/client-options.rst
@@ -618,9 +618,8 @@
group is treated as best.
The probe carries the same control-channel wrapping as a normal
- connection (``--tls-auth`` or ``--tls-crypt``, when configured). With
- ``--tls-crypt-v2`` the remotes are left in their configured order,
- because the server cannot unwrap an out-of-band probe yet.
+ connection (``--tls-auth``, ``--tls-crypt`` or ``--tls-crypt-v2``,
+ when configured).
Only UDP remotes are probed, and only when there are at least two
remotes; remotes reached through a SOCKS proxy are not probed. All
diff --git a/src/openvpn/oob_client.c b/src/openvpn/oob_client.c
index 286b08e..fb59104 100644
--- a/src/openvpn/oob_client.c
+++ b/src/openvpn/oob_client.c
@@ -80,9 +80,7 @@
* the tls_auth_standalone the server uses to answer it. With neither tls-auth
* nor tls-crypt configured the context stays in TLS_WRAP_NONE and the probe is
* sent in plaintext, exactly as before; with either configured the probe is
- * authenticated/encrypted like any other control packet. Returns NULL (and
- * logs) for configurations the probe cannot wrap yet, in which case the caller
- * skips probing and keeps the configured remote order. */
+ * authenticated/encrypted like any other control packet. */
static struct tls_auth_standalone *
oob_probe_init_tls_auth_standalone(struct context *c, struct gc_arena *gc)
{
@@ -95,19 +93,9 @@
* supported; the first entry's wrapping is used for all.) */
const struct connection_entry *ce = c->options.connection_list->array[0];
- /* tls-crypt-v2 wraps with a per-client key the server only learns from the
- * wrapped client key (WKc) carried in the TLS handshake. An out-of-band
- * probe carries no WKc, so the server cannot unwrap it; skip probing
rather
- * than send something unverifiable. */
- if (ce->tls_crypt_v2_file)
- {
- msg(D_LOW, "server-probe: not supported with tls-crypt-v2; using
configured order");
- return NULL;
- }
-
- /* Load the tls-auth/tls-crypt key material into c->c1.ks (a no-op if
neither
- * is configured). This is run again per-connection later; calling it early
- * here is harmless. */
+ /* Load the tls-auth/tls-crypt(-v2) key material into c->c1.ks (a no-op if
+ * none is configured). This is run again per-connection later; calling it
+ * early here is harmless. */
do_init_tls_wrap_key(c, ce);
struct tls_options to;
@@ -116,6 +104,15 @@
to.replay_window = c->options.replay_window;
to.replay_time = c->options.replay_time;
+ /* tls-crypt-v2 wraps with a per-client key the server learns from the
+ * wrapped client key (WKc). init_tls_wrap_ctx() loaded the per-client key
+ * into the wrap context; make the WKc available too so the probe can
append
+ * it (as a P_CONTROL_OOB_WKC_V1 message), mirroring do_init_crypto_tls().
*/
+ if (ce->tls_crypt_v2_file)
+ {
+ to.tls_wrap.tls_crypt_v2_wkc = &c->c1.ks.tls_crypt_v2_wkc;
+ }
+
struct tls_auth_standalone *tas = tls_auth_standalone_init(&to, gc);
/* Control-channel frame and work buffers, mirroring do_init_frame_tls().
*/
@@ -567,14 +564,8 @@
struct gc_arena gc = gc_new();
/* Wrapping context for the probe (tls-auth/tls-crypt, or plaintext if
- * neither). NULL means this configuration cannot be probed; keep the
- * configured order. */
+ * neither). */
struct tls_auth_standalone *tas = oob_probe_init_tls_auth_standalone(c,
&gc);
- if (!tas)
- {
- gc_free(&gc);
- return;
- }
/* A single random session id identifies all of our probes; servers echo it
* back in the reply's peer_session_id, letting us reject spoofed replies.
*/
@@ -633,8 +624,15 @@
return;
}
+ /* With tls-crypt-v2 the probe must carry the wrapped client key so the
+ * server can recover the per-client key; that is a P_CONTROL_OOB_WKC_V1
+ * message. Otherwise (tls-crypt v1, tls-auth, or plaintext) it is a plain
+ * P_CONTROL_OOB_V1. */
+ const bool is_v2 = (tas->tls_wrap.tls_crypt_v2_wkc != NULL);
+ const int probe_opcode = is_v2 ? P_CONTROL_OOB_WKC_V1 : P_CONTROL_OOB_V1;
+
struct buffer probe =
- tls_wrap_oob_standalone(&tas->tls_wrap, tas, &client_sid, &payload,
P_CONTROL_OOB_V1);
+ tls_wrap_oob_standalone(&tas->tls_wrap, tas, &client_sid, &payload,
probe_opcode);
if (!BLEN(&probe))
{
msg(D_LOW, "server-probe: could not wrap probe packet; using
configured order");
@@ -644,9 +642,10 @@
return;
}
- const char *wrap_name = (tas->tls_wrap.mode == TLS_WRAP_CRYPT) ?
"tls-crypt"
- : (tas->tls_wrap.mode == TLS_WRAP_AUTH) ?
"tls-auth"
- : "none
(plaintext)";
+ const char *wrap_name = is_v2 ?
"tls-crypt-v2"
+ : (tas->tls_wrap.mode == TLS_WRAP_CRYPT) ?
"tls-crypt"
+ : (tas->tls_wrap.mode == TLS_WRAP_AUTH) ?
"tls-auth"
+ : "none
(plaintext)";
msg(D_LOW, "server-probe: probing %d remote(s) with a %d ms window,
control-channel wrapping: %s",
l->len, OOB_PROBE_WINDOW_MS, wrap_name);
--
To view, visit http://gerrit.openvpn.net/c/openvpn/+/1759?usp=email
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Gerrit-MessageType: newpatchset
Gerrit-Project: openvpn
Gerrit-Branch: master
Gerrit-Change-Id: I5cc100dd7dc810d7d1e6f29bb57584905fbcf4a0
Gerrit-Change-Number: 1759
Gerrit-PatchSet: 18
Gerrit-Owner: stipa <[email protected]>
Gerrit-Reviewer: plaisthos <[email protected]>
Gerrit-CC: openvpn-devel <[email protected]>
Gerrit-Attention: plaisthos <[email protected]>
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