Make waiting on auth an explicit state in the context state machine
Previously we relied on checking tls_authentication_status to check
wether to determine if the context auth state is actually valid or not.
This patch eliminates that check by introducing waiting on the
authentication as extra state in the context auth, state machine.
The simplification and reorganization of the state machine in this
and the previous patches also eliminates a number of corner cases,
including the specific one that lead to CVE-2020-15078.
Patch v3: Fix ccd config from management being ignored
Patch v4: Fix race condition, we need to accept the config from
management if we are in CAS_WAITING_AUTH or earlier states
and not just in CAS_WAITING_AUTH state
CVE: 2020-15078
Signed-off-by: Arne Schwabe <arne@rfc2549.org>
Acked-by: Antonio Quartulli <antonio@openvpn.net>
Message-Id: <20210604143938.779193-1-arne@rfc2549.org>
URL: https://www.mail-archive.com/openvpn-devel@lists.sourceforge.net/msg22491.html
Signed-off-by: Gert Doering <gert@greenie.muc.de>
Arne Schwabe authored on 2021/06/04 23:39:38Showing 3 changed files
| ... | ... |
@@ -2596,11 +2596,6 @@ static const multi_client_connect_handler client_connect_handlers[] = {
|
| 2596 | 2596 |
static void |
| 2597 | 2597 |
multi_connection_established(struct multi_context *m, struct multi_instance *mi) |
| 2598 | 2598 |
{
|
| 2599 |
- if (tls_authentication_status(mi->context.c2.tls_multi) != TLS_AUTHENTICATION_SUCCEEDED) |
|
| 2600 |
- {
|
|
| 2601 |
- return; |
|
| 2602 |
- } |
|
| 2603 |
- |
|
| 2604 | 2599 |
/* We are only called for the CAS_PENDING_x states, so we |
| 2605 | 2600 |
* can ignore other states here */ |
| 2606 | 2601 |
bool from_deferred = (mi->context.c2.tls_multi->multi_state != CAS_PENDING); |
| ... | ... |
@@ -3970,7 +3965,7 @@ management_client_auth(void *arg, |
| 3970 | 3970 |
{
|
| 3971 | 3971 |
if (auth) |
| 3972 | 3972 |
{
|
| 3973 |
- if (is_cas_pending(mi->context.c2.tls_multi->multi_state)) |
|
| 3973 |
+ if (mi->context.c2.tls_multi->multi_state <= CAS_WAITING_AUTH) |
|
| 3974 | 3974 |
{
|
| 3975 | 3975 |
set_cc_config(mi, cc_config); |
| 3976 | 3976 |
cc_config_owned = false; |
| ... | ... |
@@ -2810,7 +2810,7 @@ tls_process(struct tls_multi *multi, |
| 2810 | 2810 |
if (session->opt->mode == MODE_SERVER) |
| 2811 | 2811 |
{
|
| 2812 | 2812 |
/* On a server we continue with running connect scripts next */ |
| 2813 |
- multi->multi_state = CAS_PENDING; |
|
| 2813 |
+ multi->multi_state = CAS_WAITING_AUTH; |
|
| 2814 | 2814 |
} |
| 2815 | 2815 |
else |
| 2816 | 2816 |
{
|
| ... | ... |
@@ -3136,6 +3136,13 @@ tls_multi_process(struct tls_multi *multi, |
| 3136 | 3136 |
|
| 3137 | 3137 |
enum tls_auth_status tas = tls_authentication_status(multi); |
| 3138 | 3138 |
|
| 3139 |
+ /* If we have successfully authenticated and are still waiting for the authentication to finish |
|
| 3140 |
+ * move the state machine for the multi context forward */ |
|
| 3141 |
+ if (multi->multi_state == CAS_WAITING_AUTH && tas == TLS_AUTHENTICATION_SUCCEEDED) |
|
| 3142 |
+ {
|
|
| 3143 |
+ multi->multi_state = CAS_PENDING; |
|
| 3144 |
+ } |
|
| 3145 |
+ |
|
| 3139 | 3146 |
/* |
| 3140 | 3147 |
* If lame duck session expires, kill it. |
| 3141 | 3148 |
*/ |
| ... | ... |
@@ -511,6 +511,7 @@ struct tls_session |
| 511 | 511 |
* connect scripts/plugins */ |
| 512 | 512 |
enum multi_status {
|
| 513 | 513 |
CAS_NOT_CONNECTED, |
| 514 |
+ CAS_WAITING_AUTH, /**< TLS connection established but deferred auth not finished */ |
|
| 514 | 515 |
CAS_PENDING, |
| 515 | 516 |
CAS_PENDING_DEFERRED, |
| 516 | 517 |
CAS_PENDING_DEFERRED_PARTIAL, /**< at least handler succeeded, no result yet*/ |