This allows a server to indicate a temporary problem on the server and
allows the server to indicate how to proceed (i.e. move to the next server,
retry the same server, wait a certain time,...)
This adds options_utils.c/h to be able to unit test the new function.
Patch v2: Improve documentation, format man page better, comment that
protocol-flags is not a user usable option.
---
doc/man-sections/script-options.rst | 36 ++++++++++
src/openvpn/Makefile.am | 1 +
src/openvpn/init.c | 9 ++-
src/openvpn/openvpn.vcxproj | 2 +
src/openvpn/openvpn.vcxproj.filters | 3 +
src/openvpn/options.h | 9 ++-
src/openvpn/options_util.c | 104 +++++++++++++++++++++++++++
src/openvpn/options_util.h | 33 +++++++++
src/openvpn/push.c | 11 ++-
src/openvpn/ssl.c | 13 ++--
src/openvpn/ssl.h | 3 +
tests/unit_tests/openvpn/Makefile.am | 1 +
tests/unit_tests/openvpn/test_misc.c | 49 +++++++++++++
13 files changed, 266 insertions(+), 8 deletions(-)
create mode 100644 src/openvpn/options_util.c
create mode 100644 src/openvpn/options_util.h
diff --git a/doc/man-sections/script-options.rst
b/doc/man-sections/script-options.rst
index 6be0686d7..8a58eaad0 100644
--- a/doc/man-sections/script-options.rst
+++ b/doc/man-sections/script-options.rst
@@ -97,6 +97,42 @@ SCRIPT HOOKS
the authentication, a :code:`1` or :code:`0` must be written to the
file specified by the :code:`auth_control_file`.
+ If the file specified by :code:`auth_failed_reason` exists and has non-empty
+ content, the content of this file will be used as AUTH_FAILED message. To
+ avoid race conditions, this file should be written before
+ :code:`auth_control_file`.
+
+ This auth fail reason can be something simple like "User has been permanently
+ disabled" but there are also some special auth failed messages.
+
+ The ``TEMP`` message indicates that the authentication
+ temporarily failed and that the client should continue to retry to connect.
+ The server can optionally give a user readable message and hint the client a
+ behavior how to proceed. The keywords of the ``AUTH_FAILED,TEMP`` message
+ are comma separated keys/values and provide a hint to the client how to
+ proceed. Currently defined keywords are:
+
+ ``backoff`` :code:`s`
+ instructs the client to wait at least :code:`s` seconds before the next
+ connection attempt. If the client already uses a higher delay for
+ reconnection attempt, the delay will not be shortened.
+
+ ``advance addr``
+ Instructs the client to reconnect to the next (IP) address of the
+ current server.
+
+ ``advance remote``
+ Instructs the client to skip the remaining IP addresses of the current
+ server and instead connect to the next server specified in the
+ configuration file.
+
+ ``advance no``
+ Instructs the client to retry connecting to the same server again.
+
+ For example, the message ``TEMP[backoff 42,advance no]: No free IP
addresses``
+ indicates that the VPN connection can currently not succeed and instructs
+ the client to retry in 42 seconds again.
+
When deferred authentication is in use, the script can also request
pending authentication by writing to the file specified by the
:code:`auth_pending_file`. The first line must be the timeout in
diff --git a/src/openvpn/Makefile.am b/src/openvpn/Makefile.am
index 577294804..a619aac38 100644
--- a/src/openvpn/Makefile.am
+++ b/src/openvpn/Makefile.am
@@ -95,6 +95,7 @@ openvpn_SOURCES = \
pkcs11_mbedtls.c \
openvpn.c openvpn.h \
options.c options.h \
+ options_util.c options_util.h \
otime.c otime.h \
packet_id.c packet_id.h \
perf.c perf.h \
diff --git a/src/openvpn/init.c b/src/openvpn/init.c
index b0c62a859..b2a1e92a5 100644
--- a/src/openvpn/init.c
+++ b/src/openvpn/init.c
@@ -483,13 +483,15 @@ next_connection_entry(struct context *c)
/* Check if there is another resolved address to try for
* the current connection */
if (c->c1.link_socket_addr.current_remote
- && c->c1.link_socket_addr.current_remote->ai_next)
+ && c->c1.link_socket_addr.current_remote->ai_next
+ && !c->options.advance_next_remote)
{
c->c1.link_socket_addr.current_remote =
c->c1.link_socket_addr.current_remote->ai_next;
}
else
{
+ c->options.advance_next_remote = false;
/* FIXME (schwabe) fix the persist-remote-ip option for real,
* this is broken probably ever since connection lists and
multiple
* remote existed
@@ -2357,6 +2359,11 @@ socket_restart_pause(struct context *c)
/* sec is less than 2^16; we can left shift it by up to 15 bits
without overflow */
sec = max_int(sec, 1) << min_int(backoff, 15);
}
+ if (c->options.server_backoff_time)
+ {
+ sec = max_int(sec, c->options.server_backoff_time);
+ c->options.server_backoff_time = 0;
+ }
if (sec > c->options.ce.connect_retry_seconds_max)
{
diff --git a/src/openvpn/openvpn.vcxproj b/src/openvpn/openvpn.vcxproj
index 860ef8926..e82be2698 100644
--- a/src/openvpn/openvpn.vcxproj
+++ b/src/openvpn/openvpn.vcxproj
@@ -306,6 +306,7 @@
<ClCompile Include="occ.c" />
<ClCompile Include="openvpn.c" />
<ClCompile Include="options.c" />
+ <ClCompile Include="options_util.c" />
<ClCompile Include="otime.c" />
<ClCompile Include="packet_id.c" />
<ClCompile Include="perf.c" />
@@ -395,6 +396,7 @@
<ClInclude Include="occ.h" />
<ClInclude Include="openvpn.h" />
<ClInclude Include="options.h" />
+ <ClInclude Include="options_util.h" />
<ClInclude Include="otime.h" />
<ClInclude Include="packet_id.h" />
<ClInclude Include="perf.h" />
diff --git a/src/openvpn/openvpn.vcxproj.filters
b/src/openvpn/openvpn.vcxproj.filters
index f76e59235..616b71ab2 100644
--- a/src/openvpn/openvpn.vcxproj.filters
+++ b/src/openvpn/openvpn.vcxproj.filters
@@ -395,6 +395,9 @@
<ClInclude Include="options.h">
<Filter>Header Files</Filter>
</ClInclude>
+ <ClInclude Include="options_util.h">
+ <Filter>Header Files</Filter>
+ </ClInclude>
<ClInclude Include="otime.h">
<Filter>Header Files</Filter>
</ClInclude>
diff --git a/src/openvpn/options.h b/src/openvpn/options.h
index c2937dc37..0c1a31389 100644
--- a/src/openvpn/options.h
+++ b/src/openvpn/options.h
@@ -272,10 +272,17 @@ struct options
struct connection_list *connection_list;
struct remote_list *remote_list;
- /* Do not advanced the connection or remote addr list*/
+ /* Do not advance the connection or remote addr list*/
bool no_advance;
+ /* Advance directly to the next remote, skipping remaining addresses of the
+ * current remote */
+ bool advance_next_remote;
/* Counts the number of unsuccessful connection attempts */
unsigned int unsuccessful_attempts;
+ /* the server can suggest a backoff time to the client, it
+ * will still be capped by the max timeout between connections
+ * (300s by default) */
+ int server_backoff_time;
#if ENABLE_MANAGEMENT
struct http_proxy_options *http_proxy_override;
diff --git a/src/openvpn/options_util.c b/src/openvpn/options_util.c
new file mode 100644
index 000000000..d8a7e2343
--- /dev/null
+++ b/src/openvpn/options_util.c
@@ -0,0 +1,104 @@
+/*
+ * OpenVPN -- An application to securely tunnel IP networks
+ * over a single TCP/UDP port, with support for SSL/TLS-based
+ * session authentication and key exchange,
+ * packet encryption, packet authentication, and
+ * packet compression.
+ *
+ * Copyright (C) 2002-2022 OpenVPN Inc <sa...@openvpn.net>
+ * Copyright (C) 2010-2021 Fox Crypto B.V. <open...@foxcrypto.com>
+ *
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License version 2
+ * as published by the Free Software Foundation.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
+ * GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License along
+ * with this program; if not, write to the Free Software Foundation, Inc.,
+ * 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA.
+ */
+
+#ifdef HAVE_CONFIG_H
+#include "config.h"
+#elif defined(_MSC_VER)
+#include "config-msvc.h"
+#endif
+
+#include "syshead.h"
+
+#include "options_util.h"
+
+const char *
+parse_auth_failed_temp(struct options *o, const struct buffer *buf)
+{
+ struct gc_arena gc = gc_new();
+ char *m = string_alloc(BSTR(buf), &gc);
+ /* skip TEMP */
+ m += strlen("TEMP");
+ const char *message = BSTR(buf) + 4;
+
+
+ /* Check if the message uses the TEMP[flags]: message format*/
+ char *endofflags = strstr(m, "]");
+
+ /* Temporary failure from the server */
+ if (m[0] == '[' && endofflags)
+ {
+ message = strstr(BSTR(buf), "]") + 1;
+ /* null terminate the substring to only looks for flags between [ and
] */
+ *endofflags = '\x00';
+ const char *token = strtok(m, "[,");
+ while (token)
+ {
+ if (!strncmp(token, "backoff ", strlen("backoff ")))
+ {
+ if (sscanf(token, "backoff %d", &o->server_backoff_time) != 1)
+ {
+ msg(D_PUSH, "invalid AUTH_FAIL,TEMP flag: %s", token);
+ o->server_backoff_time = 0;
+ }
+ }
+ else if (!strncmp(token, "advance ", strlen("advance ")))
+ {
+ token += strlen("advance ");
+ if (!strcmp(token, "no"))
+ {
+ o->no_advance = true;
+ }
+ else if (!strcmp(token, "remote"))
+ {
+ o->advance_next_remote = true;
+ o->no_advance = false;
+ }
+ else if (!strcmp(token, "addr"))
+ {
+ /* Go on to the next remote */
+ o->no_advance = false;
+ }
+ }
+ else
+ {
+ msg(D_PUSH_ERRORS, "WARNING: unknown AUTH_FAIL,TEMP flag: %s",
token);
+ }
+ token = strtok(NULL, "[,");
+ }
+ }
+
+ /* Look for the message in the original buffer to safely be
+ * able to return it */
+ if (!message || message[0] != ':')
+ {
+ message = "";
+ }
+ else
+ {
+ /* Skip the : at the beginning */
+ message += 1;
+ }
+ gc_free(&gc);
+ return message;
+}
\ No newline at end of file
diff --git a/src/openvpn/options_util.h b/src/openvpn/options_util.h
new file mode 100644
index 000000000..9785bb239
--- /dev/null
+++ b/src/openvpn/options_util.h
@@ -0,0 +1,33 @@
+/*
+ * OpenVPN -- An application to securely tunnel IP networks
+ * over a single TCP/UDP port, with support for SSL/TLS-based
+ * session authentication and key exchange,
+ * packet encryption, packet authentication, and
+ * packet compression.
+ *
+ * Copyright (C) 2002-2022 OpenVPN Inc <sa...@openvpn.net>
+ * Copyright (C) 2010-2021 Fox Crypto B.V. <open...@foxcrypto.com>
+ *
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License version 2
+ * as published by the Free Software Foundation.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
+ * GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License along
+ * with this program; if not, write to the Free Software Foundation, Inc.,
+ * 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA.
+ */
+
+#ifndef OPTIONS_UTIL_H_
+#define OPTIONS_UTIL_H_
+
+#include "options.h"
+
+const char *
+parse_auth_failed_temp(struct options *o, const struct buffer *buf);
+
+#endif
\ No newline at end of file
diff --git a/src/openvpn/push.c b/src/openvpn/push.c
index 1c4e637e4..3b3dce642 100644
--- a/src/openvpn/push.c
+++ b/src/openvpn/push.c
@@ -38,6 +38,7 @@
#include "memdbg.h"
#include "ssl_util.h"
+#include "options_util.h"
static char push_reply_cmd[] = "PUSH_REPLY";
@@ -51,7 +52,6 @@ void
receive_auth_failed(struct context *c, const struct buffer *buffer)
{
msg(M_VERB0, "AUTH: Received control message: %s", BSTR(buffer));
- c->options.no_advance = true;
if (!c->options.pull)
{
@@ -64,15 +64,22 @@ receive_auth_failed(struct context *c, const struct buffer
*buffer)
* contains further flags */
bool authfail_extended = buf_string_compare_advance(&buf, "AUTH_FAILED,");
+ if (authfail_extended && buf_string_match_head_str(&buf, "TEMP"))
+ {
+ parse_auth_failed_temp(&c->options, &buf);
+ c->sig->signal_received = SIGUSR1;
+ c->sig->signal_text = "auth-temp-failure (server temporary reject)";
+ }
/* Before checking how to react on AUTH_FAILED, first check if the
* failed auth might be the result of an expired auth-token.
* Note that a server restart will trigger a generic AUTH_FAILED
* instead an AUTH_FAILED,SESSION so handle all AUTH_FAILED message
* identical for this scenario */
- if (ssl_clean_auth_token())
+ else if (ssl_clean_auth_token())
{
c->sig->signal_received = SIGUSR1; /* SOFT-SIGUSR1 -- Auth failure
error */
c->sig->signal_text = "auth-failure (auth-token)";
+ c->options.no_advance = true;
}
else
{
diff --git a/src/openvpn/ssl.c b/src/openvpn/ssl.c
index 4506b7504..f11b3afb3 100644
--- a/src/openvpn/ssl.c
+++ b/src/openvpn/ssl.c
@@ -1943,14 +1943,19 @@ push_peer_info(struct buffer *buf, struct tls_session
*session)
/* support for exit notify via control channel */
iv_proto |= IV_PROTO_CC_EXIT_NOTIFY;
- /* support for receiving push_reply before sending
- * push request, also signal that the client wants
- * to get push-reply messages without without requiring a round
- * trip for a push request message*/
if (session->opt->pull)
{
+ /* support for receiving push_reply before sending
+ * push request, also signal that the client wants
+ * to get push-reply messages without requiring a round
+ * trip for a push request message*/
iv_proto |= IV_PROTO_REQUEST_PUSH;
+
+ /* Support keywords in the AUTH_PENDING control message */
iv_proto |= IV_PROTO_AUTH_PENDING_KW;
+
+ /* support for AUTH_FAIL,TEMP control message */
+ iv_proto |= IV_PROTO_AUTH_FAIL_TEMP;
}
/* support for Negotiable Crypto Parameters */
diff --git a/src/openvpn/ssl.h b/src/openvpn/ssl.h
index 1b8b736b9..981bb3403 100644
--- a/src/openvpn/ssl.h
+++ b/src/openvpn/ssl.h
@@ -93,6 +93,9 @@
* result. */
#define IV_PROTO_NCP_P2P (1<<5)
+/** Support for AUTH_FAIL,TEMP messages */
+#define IV_PROTO_AUTH_FAIL_TEMP (1<<6)
+
/** Support for explicit exit notify via control channel */
#define IV_PROTO_CC_EXIT_NOTIFY (1<<7)
diff --git a/tests/unit_tests/openvpn/Makefile.am
b/tests/unit_tests/openvpn/Makefile.am
index 63b53a6ac..65cf9549c 100644
--- a/tests/unit_tests/openvpn/Makefile.am
+++ b/tests/unit_tests/openvpn/Makefile.am
@@ -176,5 +176,6 @@ misc_testdriver_LDFLAGS = @TEST_LDFLAGS@
misc_testdriver_SOURCES = test_misc.c mock_msg.c \
mock_get_random.c \
$(openvpn_srcdir)/buffer.c \
+ $(openvpn_srcdir)/options_util.c \
$(openvpn_srcdir)/ssl_util.c \
$(openvpn_srcdir)/platform.c
diff --git a/tests/unit_tests/openvpn/test_misc.c
b/tests/unit_tests/openvpn/test_misc.c
index 636fc45d6..802307fb7 100644
--- a/tests/unit_tests/openvpn/test_misc.c
+++ b/tests/unit_tests/openvpn/test_misc.c
@@ -37,6 +37,7 @@
#include <cmocka.h>
#include "ssl_util.h"
+#include "options_util.h"
static void
test_compat_lzo_string(void **state)
@@ -72,8 +73,56 @@ test_compat_lzo_string(void **state)
gc_free(&gc);
}
+static void
+test_auth_fail_temp_no_flags(void **state)
+{
+ struct options o;
+
+ struct buffer buf;
+ const char *teststr = "TEMP:There are no flags here [really not]";
+
+ buf_set_read(&buf, (uint8_t *)teststr,strlen(teststr));
+
+ const char *msg = parse_auth_failed_temp(&o, &buf);
+ assert_string_equal(msg, "There are no flags here [really not]");
+}
+
+static void
+test_auth_fail_temp_flags(void **state)
+{
+ struct options o;
+
+ struct buffer buf;
+ const char *teststr = "TEMP[backoff 42,advance no]";
+
+ buf_set_read(&buf, (uint8_t *)teststr,strlen(teststr));
+
+ const char *msg = parse_auth_failed_temp(&o, &buf);
+ assert_string_equal(msg, "");
+ assert_int_equal(o.server_backoff_time, 42);
+ assert_int_equal(o.no_advance, true);
+}
+
+static void
+test_auth_fail_temp_flags_msg(void **state)
+{
+ struct options o;
+
+ struct buffer buf;
+ const char *teststr = "TEMP[advance remote,backoff 77]:go round and round";
+
+ buf_set_read(&buf, (uint8_t *)teststr,strlen(teststr));
+
+ const char *msg = parse_auth_failed_temp(&o, &buf);
+ assert_string_equal(msg, "go round and round");
+ assert_int_equal(o.server_backoff_time, 77);
+}
+
const struct CMUnitTest misc_tests[] = {
cmocka_unit_test(test_compat_lzo_string),
+ cmocka_unit_test(test_auth_fail_temp_no_flags),
+ cmocka_unit_test(test_auth_fail_temp_flags),
+ cmocka_unit_test(test_auth_fail_temp_flags_msg),
};
int
--
2.32.0 (Apple Git-132)
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