Attention is currently required from: flichtenheld, plaisthos, reynir.
Hello flichtenheld, plaisthos,
I'd like you to reexamine a change. Please visit
http://gerrit.openvpn.net/c/openvpn/+/555?usp=email
to look at the new patch set (#3).
The following approvals got outdated and were removed:
Code-Review+2 by flichtenheld, Code-Review+2 by plaisthos
The change is no longer submittable: Code-Review and checks~ChecksSubmitRule
are unsatisfied now.
Change subject: Only schedule_exit() once
......................................................................
Only schedule_exit() once
If an exit has already been scheduled we should not schedule it again.
Otherwise, the exit signal is never emitted if the peer reschedules the
exit before the timeout occurs.
schedule_exit() now only takes the context as argument. The signal is
hard coded to SIGTERM, and the interval is read directly from the
context options.
Furthermore, schedule_exit() now returns a bool signifying whether an
exit was scheduled; false if exit is already scheduled. The call sites
are updated accordingly. A notable difference is that management is only
notified *once* when an exit is scheduled - we no longer notify
management on redundant exit.
This patch was assigned a CVE number after already reviewed and ACKed,
because it was discovered that a misbehaving client can use the (now
fixed) server behaviour to avoid being disconnected by means of a
managment interface "client-kill" command - the security issue here is
"client can circumvent security policy set by management interface".
This only affects previously authenticated clients, and only management
client-kill, so normal renegotion / AUTH_FAIL ("your session ends") is not
affected.
CVE: 2024-28882
Change-Id: I9457f005f4ba970502e6b667d9dc4299a588d661
Signed-off-by: Reynir Björnsson <rey...@reynir.dk>
---
M src/openvpn/forward.c
M src/openvpn/forward.h
M src/openvpn/push.c
3 files changed, 19 insertions(+), 10 deletions(-)
git pull ssh://gerrit.openvpn.net:29418/openvpn refs/changes/55/555/3
diff --git a/src/openvpn/forward.c b/src/openvpn/forward.c
index 8d10f25..01165b2 100644
--- a/src/openvpn/forward.c
+++ b/src/openvpn/forward.c
@@ -514,17 +514,24 @@
}
/*
- * Schedule a signal n_seconds from now.
+ * Schedule a SIGTERM signal c->options.scheduled_exit_interval seconds from
now.
*/
-void
-schedule_exit(struct context *c, const int n_seconds, const int signal)
+bool
+schedule_exit(struct context *c)
{
+ const int n_seconds = c->options.scheduled_exit_interval;
+ /* don't reschedule if already scheduled. */
+ if (event_timeout_defined(&c->c2.scheduled_exit))
+ {
+ return false;
+ }
tls_set_single_session(c->c2.tls_multi);
update_time();
reset_coarse_timers(c);
event_timeout_init(&c->c2.scheduled_exit, n_seconds, now);
- c->c2.scheduled_exit_signal = signal;
+ c->c2.scheduled_exit_signal = SIGTERM;
msg(D_SCHED_EXIT, "Delayed exit in %d seconds", n_seconds);
+ return true;
}
/*
diff --git a/src/openvpn/forward.h b/src/openvpn/forward.h
index 6fb5a18..422c591 100644
--- a/src/openvpn/forward.h
+++ b/src/openvpn/forward.h
@@ -303,7 +303,7 @@
void process_ip_header(struct context *c, unsigned int flags, struct buffer
*buf);
-void schedule_exit(struct context *c, const int n_seconds, const int signal);
+bool schedule_exit(struct context *c);
static inline struct link_socket_info *
get_link_socket_info(struct context *c)
diff --git a/src/openvpn/push.c b/src/openvpn/push.c
index 1b406b9..17e7e80 100644
--- a/src/openvpn/push.c
+++ b/src/openvpn/push.c
@@ -204,7 +204,11 @@
* */
if (c->options.mode == MODE_SERVER)
{
- schedule_exit(c, c->options.scheduled_exit_interval, SIGTERM);
+ if (!schedule_exit(c))
+ {
+ /* Return early when we don't need to notify management */
+ return;
+ }
}
else
{
@@ -391,7 +395,7 @@
void
send_auth_failed(struct context *c, const char *client_reason)
{
- if (event_timeout_defined(&c->c2.scheduled_exit))
+ if (!schedule_exit(c))
{
msg(D_TLS_DEBUG, "exit already scheduled for context");
return;
@@ -401,8 +405,6 @@
static const char auth_failed[] = "AUTH_FAILED";
size_t len;
- schedule_exit(c, c->options.scheduled_exit_interval, SIGTERM);
-
len = (client_reason ? strlen(client_reason)+1 : 0) + sizeof(auth_failed);
if (len > PUSH_BUNDLE_SIZE)
{
@@ -492,7 +494,7 @@
void
send_restart(struct context *c, const char *kill_msg)
{
- schedule_exit(c, c->options.scheduled_exit_interval, SIGTERM);
+ schedule_exit(c);
send_control_channel_string(c, kill_msg ? kill_msg : "RESTART", D_PUSH);
}
--
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Gerrit-Project: openvpn
Gerrit-Branch: master
Gerrit-Change-Id: I9457f005f4ba970502e6b667d9dc4299a588d661
Gerrit-Change-Number: 555
Gerrit-PatchSet: 3
Gerrit-Owner: reynir <rey...@reynir.dk>
Gerrit-Reviewer: flichtenheld <fr...@lichtenheld.com>
Gerrit-Reviewer: plaisthos <arne-open...@rfc2549.org>
Gerrit-Reviewer: reynir <rey...@reynir.dk>
Gerrit-CC: openvpn-devel <openvpn-devel@lists.sourceforge.net>
Gerrit-Attention: plaisthos <arne-open...@rfc2549.org>
Gerrit-Attention: flichtenheld <fr...@lichtenheld.com>
Gerrit-Attention: reynir <rey...@reynir.dk>
Gerrit-MessageType: newpatchset
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