Attention is currently required from: plaisthos.
Hello plaisthos,
I'd like you to do a code review.
Please visit
http://gerrit.openvpn.net/c/openvpn/+/1759?usp=email
to review the following change.
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
---
M src/openvpn/oob_client.c
1 file changed, 24 insertions(+), 17 deletions(-)
git pull ssh://gerrit.openvpn.net:29418/openvpn refs/changes/59/1759/1
diff --git a/src/openvpn/oob_client.c b/src/openvpn/oob_client.c
index 2b1b732..7e26392 100644
--- a/src/openvpn/oob_client.c
+++ b/src/openvpn/oob_client.c
@@ -84,19 +84,9 @@
* 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;
@@ -105,6 +95,15 @@
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 init_instance(). */
+ 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().
*/
@@ -467,8 +466,15 @@
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");
@@ -478,9 +484,10 @@
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);
--
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Gerrit-MessageType: newchange
Gerrit-Project: openvpn
Gerrit-Branch: master
Gerrit-Change-Id: I5cc100dd7dc810d7d1e6f29bb57584905fbcf4a0
Gerrit-Change-Number: 1759
Gerrit-PatchSet: 1
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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