From: Lev Stipakov <lev.stipa...@f-secure.com>
v3:
* move assert outside of loop
* add max-clients value check to options
v2:
* Add round brackets for clarity
* Rephrase comment
Support for disabled peer-id
When peer-id value is 0xFFFFFF, server should ignore it and treat packet
in a same way as P_DATA_V1.
---
src/openvpn/mudp.c | 13 ++++++++++---
src/openvpn/multi.c | 3 ++-
src/openvpn/options.c | 5 +++++
3 files changed, 17 insertions(+), 4 deletions(-)
diff --git a/src/openvpn/mudp.c b/src/openvpn/mudp.c
index 21a7e97..59795eb 100644
--- a/src/openvpn/mudp.c
+++ b/src/openvpn/mudp.c
@@ -64,12 +64,16 @@ multi_get_create_instance_udp (struct multi_context *m,
bool *floated)
struct hash_bucket *bucket = hash_bucket (hash, hv);
uint8_t* ptr = BPTR(&m->top.c2.buf);
uint8_t op = ptr[0] >> P_OPCODE_SHIFT;
+ bool v2 = (op == P_DATA_V2) && (m->top.c2.buf.len >= (1 + 3));
+ bool peer_id_disabled = false;
/* make sure buffer has enough length to read opcode (1 byte) and
peer-id (3 bytes) */
- if (op == P_DATA_V2 && m->top.c2.buf.len >= (1 + 3))
+ if (v2)
{
uint32_t peer_id = ntohl(*(uint32_t*)ptr) & 0xFFFFFF;
- if ((peer_id < m->max_clients) && (m->instances[peer_id]))
+ peer_id_disabled = (peer_id == 0xFFFFFF);
+
+ if (!peer_id_disabled && (peer_id < m->max_clients) &&
(m->instances[peer_id]))
{
mi = m->instances[peer_id];
@@ -84,7 +88,7 @@ multi_get_create_instance_udp (struct multi_context *m, bool
*floated)
}
}
}
- else
+ if (!v2 || peer_id_disabled)
{
he = hash_lookup_fast (hash, bucket, &real, hv);
if (he)
@@ -107,6 +111,9 @@ multi_get_create_instance_udp (struct multi_context *m,
bool *floated)
hash_add_fast (hash, bucket, &mi->real, hv, mi);
mi->did_real_hash = true;
+ /* max_clients must be less then max peer-id value */
+ ASSERT(m->max_clients < 0xFFFFFF);
+
for (i = 0; i < m->max_clients; ++i)
{
if (!m->instances[i])
diff --git a/src/openvpn/multi.c b/src/openvpn/multi.c
index ba7f2c0..73b211e 100644
--- a/src/openvpn/multi.c
+++ b/src/openvpn/multi.c
@@ -605,7 +605,8 @@ multi_close_instance (struct multi_context *m,
}
#endif
- m->instances[mi->context.c2.tls_multi->peer_id] = NULL;
+ if (mi->context.c2.tls_multi->peer_id != 0xFFFFFF)
+ m->instances[mi->context.c2.tls_multi->peer_id] = NULL;
schedule_remove_entry (m->schedule, (struct schedule_entry *) mi);
diff --git a/src/openvpn/options.c b/src/openvpn/options.c
index c9688c3..493ffe6 100644
--- a/src/openvpn/options.c
+++ b/src/openvpn/options.c
@@ -5893,6 +5893,11 @@ add_option (struct options *options,
msg (msglevel, "--max-clients must be at least 1");
goto err;
}
+ if (max_clients >= 0xFFFFFF) /* max peer-id value */
+ {
+ msg (msglevel, "--max-clients must be less than 0xFFFFFF");
+ goto err;
+ }
options->max_clients = max_clients;
}
else if (streq (p[0], "max-routes-per-client") && p[1] && !p[2])
--
1.9.1
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