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authorAlexander Chernavin <achernavin@netgate.com>2022-07-20 13:01:42 +0000
committerMatthew Smith <mgsmith@netgate.com>2022-08-09 15:42:43 +0000
commita6328e51e0c831ba3f0f4977f776491ac44eaec5 (patch)
tree2824c830f35554ed16887be32065d48f66809c34 /src/plugins/wireguard/wireguard_cookie.c
parentfd2417b2a42e34062e3d07875e5c4e11922513d5 (diff)
wireguard: add handshake rate limiting support
Type: feature With this change, if being under load a handshake message with both valid mac1 and mac2 is received, the peer will be rate limited. Cover this with tests. Signed-off-by: Alexander Chernavin <achernavin@netgate.com> Change-Id: Id8d58bb293a7975c3d922c48b4948fd25e20af4b
Diffstat (limited to 'src/plugins/wireguard/wireguard_cookie.c')
-rw-r--r--src/plugins/wireguard/wireguard_cookie.c147
1 files changed, 147 insertions, 0 deletions
diff --git a/src/plugins/wireguard/wireguard_cookie.c b/src/plugins/wireguard/wireguard_cookie.c
index 595b8770e56..4ebbfa0fa63 100644
--- a/src/plugins/wireguard/wireguard_cookie.c
+++ b/src/plugins/wireguard/wireguard_cookie.c
@@ -34,6 +34,11 @@ static void cookie_checker_make_cookie (vlib_main_t *vm, cookie_checker_t *,
uint8_t[COOKIE_COOKIE_SIZE],
ip46_address_t *ip, u16 udp_port);
+static void ratelimit_init (ratelimit_t *, ratelimit_entry_t *);
+static void ratelimit_deinit (ratelimit_t *);
+static void ratelimit_gc (ratelimit_t *, bool);
+static bool ratelimit_allow (ratelimit_t *, ip46_address_t *);
+
/* Public Functions */
void
cookie_maker_init (cookie_maker_t * cp, const uint8_t key[COOKIE_INPUT_SIZE])
@@ -44,6 +49,14 @@ cookie_maker_init (cookie_maker_t * cp, const uint8_t key[COOKIE_INPUT_SIZE])
}
void
+cookie_checker_init (cookie_checker_t *cc, ratelimit_entry_t *pool)
+{
+ clib_memset (cc, 0, sizeof (*cc));
+ ratelimit_init (&cc->cc_ratelimit_v4, pool);
+ ratelimit_init (&cc->cc_ratelimit_v6, pool);
+}
+
+void
cookie_checker_update (cookie_checker_t * cc, uint8_t key[COOKIE_INPUT_SIZE])
{
if (key)
@@ -59,6 +72,13 @@ cookie_checker_update (cookie_checker_t * cc, uint8_t key[COOKIE_INPUT_SIZE])
}
void
+cookie_checker_deinit (cookie_checker_t *cc)
+{
+ ratelimit_deinit (&cc->cc_ratelimit_v4);
+ ratelimit_deinit (&cc->cc_ratelimit_v6);
+}
+
+void
cookie_checker_create_payload (vlib_main_t *vm, cookie_checker_t *cc,
message_macs_t *cm,
uint8_t nonce[COOKIE_NONCE_SIZE],
@@ -146,6 +166,13 @@ cookie_checker_validate_macs (vlib_main_t *vm, cookie_checker_t *cc,
if (clib_memcmp (our_cm.mac2, cm->mac2, COOKIE_MAC_SIZE) != 0)
return VALID_MAC_BUT_NO_COOKIE;
+ /* If the mac2 is valid, we may want to rate limit the peer */
+ ratelimit_t *rl;
+ rl = ip46_address_is_ip4 (ip) ? &cc->cc_ratelimit_v4 : &cc->cc_ratelimit_v6;
+
+ if (!ratelimit_allow (rl, ip))
+ return VALID_MAC_WITH_COOKIE_BUT_RATELIMITED;
+
return VALID_MAC_WITH_COOKIE;
}
@@ -213,6 +240,126 @@ cookie_checker_make_cookie (vlib_main_t *vm, cookie_checker_t *cc,
blake2s_final (&state, cookie, COOKIE_COOKIE_SIZE);
}
+static void
+ratelimit_init (ratelimit_t *rl, ratelimit_entry_t *pool)
+{
+ rl->rl_pool = pool;
+}
+
+static void
+ratelimit_deinit (ratelimit_t *rl)
+{
+ ratelimit_gc (rl, /* force */ true);
+ hash_free (rl->rl_table);
+}
+
+static void
+ratelimit_gc (ratelimit_t *rl, bool force)
+{
+ u32 r_key;
+ u32 r_idx;
+ ratelimit_entry_t *r;
+
+ if (force)
+ {
+ /* clang-format off */
+ hash_foreach (r_key, r_idx, rl->rl_table, {
+ r = pool_elt_at_index (rl->rl_pool, r_idx);
+ pool_put (rl->rl_pool, r);
+ });
+ /* clang-format on */
+ return;
+ }
+
+ f64 now = vlib_time_now (vlib_get_main ());
+
+ if ((rl->rl_last_gc + ELEMENT_TIMEOUT) < now)
+ {
+ u32 *r_key_to_del = NULL;
+ u32 *pr_key;
+
+ rl->rl_last_gc = now;
+
+ /* clang-format off */
+ hash_foreach (r_key, r_idx, rl->rl_table, {
+ r = pool_elt_at_index (rl->rl_pool, r_idx);
+ if ((r->r_last_time + ELEMENT_TIMEOUT) < now)
+ {
+ vec_add1 (r_key_to_del, r_key);
+ pool_put (rl->rl_pool, r);
+ }
+ });
+ /* clang-format on */
+
+ vec_foreach (pr_key, r_key_to_del)
+ {
+ hash_unset (rl->rl_table, *pr_key);
+ }
+
+ vec_free (r_key_to_del);
+ }
+}
+
+static bool
+ratelimit_allow (ratelimit_t *rl, ip46_address_t *ip)
+{
+ u32 r_key;
+ uword *p;
+ u32 r_idx;
+ ratelimit_entry_t *r;
+ f64 now = vlib_time_now (vlib_get_main ());
+
+ if (ip46_address_is_ip4 (ip))
+ /* Use all 4 bytes of IPv4 address */
+ r_key = ip->ip4.as_u32;
+ else
+ /* Use top 8 bytes (/64) of IPv6 address */
+ r_key = ip->ip6.as_u32[0] ^ ip->ip6.as_u32[1];
+
+ /* Check if there is already an entry for the IP address */
+ p = hash_get (rl->rl_table, r_key);
+ if (p)
+ {
+ u64 tokens;
+ f64 diff;
+
+ r_idx = p[0];
+ r = pool_elt_at_index (rl->rl_pool, r_idx);
+
+ diff = now - r->r_last_time;
+ r->r_last_time = now;
+
+ tokens = r->r_tokens + diff * NSEC_PER_SEC;
+
+ if (tokens > TOKEN_MAX)
+ tokens = TOKEN_MAX;
+
+ if (tokens >= INITIATION_COST)
+ {
+ r->r_tokens = tokens - INITIATION_COST;
+ return true;
+ }
+
+ r->r_tokens = tokens;
+ return false;
+ }
+
+ /* No entry for the IP address */
+ ratelimit_gc (rl, /* force */ false);
+
+ if (hash_elts (rl->rl_table) >= RATELIMIT_SIZE_MAX)
+ return false;
+
+ pool_get (rl->rl_pool, r);
+ r_idx = r - rl->rl_pool;
+ hash_set (rl->rl_table, r_key, r_idx);
+
+ r->r_last_time = now;
+ r->r_tokens = TOKEN_MAX - INITIATION_COST;
+
+ return true;
+}
+
/*
* fd.io coding-style-patch-verification: ON
*