1 files changed, 169 insertions, 0 deletions
diff --git a/src/plugins/wireguard/wireguard_cookie.c b/src/plugins/wireguard/wireguard_cookie.c
new file mode 100755
index 00000000000..aa476f792a1
--- /dev/null
+++ b/src/plugins/wireguard/wireguard_cookie.c
@@ -0,0 +1,169 @@
+/*
+ * Copyright (c) 2020 Doc.ai and/or its affiliates.
+ * Copyright (c) 2015-2020 Jason A. Donenfeld <Jason@zx2c4.com>.
+ * Copyright (c) 2019-2020 Matt Dunwoodie <ncon@noconroy.net>.
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at:
+ *
+ *     http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+#include <stddef.h>
+#include <openssl/rand.h>
+#include <vlib/vlib.h>
+
+#include <wireguard/wireguard_cookie.h>
+#include <wireguard/wireguard.h>
+
+static void cookie_precompute_key (uint8_t *,
+				   const uint8_t[COOKIE_INPUT_SIZE],
+				   const char *);
+static void cookie_macs_mac1 (message_macs_t *, const void *, size_t,
+			      const uint8_t[COOKIE_KEY_SIZE]);
+static void cookie_macs_mac2 (message_macs_t *, const void *, size_t,
+			      const uint8_t[COOKIE_COOKIE_SIZE]);
+static void cookie_checker_make_cookie (vlib_main_t * vm, cookie_checker_t *,
+					uint8_t[COOKIE_COOKIE_SIZE],
+					ip4_address_t ip4, u16 udp_port);
+
+/* Public Functions */
+void
+cookie_maker_init (cookie_maker_t * cp, const uint8_t key[COOKIE_INPUT_SIZE])
+{
+  clib_memset (cp, 0, sizeof (*cp));
+  cookie_precompute_key (cp->cp_mac1_key, key, COOKIE_MAC1_KEY_LABEL);
+  cookie_precompute_key (cp->cp_cookie_key, key, COOKIE_COOKIE_KEY_LABEL);
+}
+
+void
+cookie_checker_update (cookie_checker_t * cc, uint8_t key[COOKIE_INPUT_SIZE])
+{
+  if (key)
+    {
+      cookie_precompute_key (cc->cc_mac1_key, key, COOKIE_MAC1_KEY_LABEL);
+      cookie_precompute_key (cc->cc_cookie_key, key, COOKIE_COOKIE_KEY_LABEL);
+    }
+  else
+    {
+      clib_memset (cc->cc_mac1_key, 0, sizeof (cc->cc_mac1_key));
+      clib_memset (cc->cc_cookie_key, 0, sizeof (cc->cc_cookie_key));
+    }
+}
+
+void
+cookie_maker_mac (cookie_maker_t * cp, message_macs_t * cm, void *buf,
+		  size_t len)
+{
+  len = len - sizeof (message_macs_t);
+  cookie_macs_mac1 (cm, buf, len, cp->cp_mac1_key);
+
+  clib_memcpy (cp->cp_mac1_last, cm->mac1, COOKIE_MAC_SIZE);
+  cp->cp_mac1_valid = 1;
+
+  if (!wg_birthdate_has_expired (cp->cp_birthdate,
+				 COOKIE_SECRET_MAX_AGE -
+				 COOKIE_SECRET_LATENCY))
+    cookie_macs_mac2 (cm, buf, len, cp->cp_cookie);
+  else
+    clib_memset (cm->mac2, 0, COOKIE_MAC_SIZE);
+}
+
+enum cookie_mac_state
+cookie_checker_validate_macs (vlib_main_t * vm, cookie_checker_t * cc,
+			      message_macs_t * cm, void *buf, size_t len,
+			      bool busy, ip4_address_t ip4, u16 udp_port)
+{
+  message_macs_t our_cm;
+  uint8_t cookie[COOKIE_COOKIE_SIZE];
+
+  len = len - sizeof (message_macs_t);
+  cookie_macs_mac1 (&our_cm, buf, len, cc->cc_mac1_key);
+
+  /* If mac1 is invald, we want to drop the packet */
+  if (clib_memcmp (our_cm.mac1, cm->mac1, COOKIE_MAC_SIZE) != 0)
+    return INVALID_MAC;
+
+  if (!busy)
+    return VALID_MAC_BUT_NO_COOKIE;
+
+  cookie_checker_make_cookie (vm, cc, cookie, ip4, udp_port);
+  cookie_macs_mac2 (&our_cm, buf, len, cookie);
+
+  /* If the mac2 is invalid, we want to send a cookie response */
+  if (clib_memcmp (our_cm.mac2, cm->mac2, COOKIE_MAC_SIZE) != 0)
+    return VALID_MAC_BUT_NO_COOKIE;
+
+  return VALID_MAC_WITH_COOKIE;
+}
+
+/* Private functions */
+static void
+cookie_precompute_key (uint8_t * key, const uint8_t input[COOKIE_INPUT_SIZE],
+		       const char *label)
+{
+  blake2s_state_t blake;
+
+  blake2s_init (&blake, COOKIE_KEY_SIZE);
+  blake2s_update (&blake, (const uint8_t *) label, strlen (label));
+  blake2s_update (&blake, input, COOKIE_INPUT_SIZE);
+  blake2s_final (&blake, key, COOKIE_KEY_SIZE);
+}
+
+static void
+cookie_macs_mac1 (message_macs_t * cm, const void *buf, size_t len,
+		  const uint8_t key[COOKIE_KEY_SIZE])
+{
+  blake2s_state_t state;
+  blake2s_init_key (&state, COOKIE_MAC_SIZE, key, COOKIE_KEY_SIZE);
+  blake2s_update (&state, buf, len);
+  blake2s_final (&state, cm->mac1, COOKIE_MAC_SIZE);
+
+}
+
+static void
+cookie_macs_mac2 (message_macs_t * cm, const void *buf, size_t len,
+		  const uint8_t key[COOKIE_COOKIE_SIZE])
+{
+  blake2s_state_t state;
+  blake2s_init_key (&state, COOKIE_MAC_SIZE, key, COOKIE_COOKIE_SIZE);
+  blake2s_update (&state, buf, len);
+  blake2s_update (&state, cm->mac1, COOKIE_MAC_SIZE);
+  blake2s_final (&state, cm->mac2, COOKIE_MAC_SIZE);
+}
+
+static void
+cookie_checker_make_cookie (vlib_main_t * vm, cookie_checker_t * cc,
+			    uint8_t cookie[COOKIE_COOKIE_SIZE],
+			    ip4_address_t ip4, u16 udp_port)
+{
+  blake2s_state_t state;
+
+  if (wg_birthdate_has_expired (cc->cc_secret_birthdate,
+				COOKIE_SECRET_MAX_AGE))
+    {
+      cc->cc_secret_birthdate = vlib_time_now (vm);
+      RAND_bytes (cc->cc_secret, COOKIE_SECRET_SIZE);
+    }
+
+  blake2s_init_key (&state, COOKIE_COOKIE_SIZE, cc->cc_secret,
+		    COOKIE_SECRET_SIZE);
+
+  blake2s_update (&state, ip4.as_u8, sizeof (ip4_address_t));	//TODO: IP6
+  blake2s_update (&state, (u8 *) & udp_port, sizeof (u16));
+  blake2s_final (&state, cookie, COOKIE_COOKIE_SIZE);
+}
+
+/*
+ * fd.io coding-style-patch-verification: ON
+ *
+ * Local Variables:
+ * eval: (c-set-style "gnu")
+ * End:
+ */