diff --git a/src/common/tortls.c b/src/common/tortls.c
index 1150c42327..4235de70fd 100644
--- a/src/common/tortls.c
+++ b/src/common/tortls.c
@@ -1228,6 +1228,17 @@ tor_tls_context_new(crypto_pk_env_t *identity, unsigned int key_lifetime)
return NULL;
}
+/** Return true if the tls object has completed more
+ * renegotiations than needed for the Tor protocol. */
+static INLINE int
+tor_tls_got_excess_renegotiations(tor_tls_t *tls)
+{
+ /** The Tor v2 server handshake needs a single renegotiation after
+ the initial SSL handshake. This means that if we ever see more
+ than 2 handshakes, we raise the flag. */
+ return (tls->server_handshake_count > 2) ? 1 : 0;
+}
+
#ifdef V2_HANDSHAKE_SERVER
/** Return true iff the cipher list suggested by the client for ssl is
* a list that indicates that the client knows how to do the v2 TLS connection
@@ -1605,6 +1616,12 @@ tor_tls_read(tor_tls_t *tls, char *cp, size_t len)
err = tor_tls_get_error(tls, r, CATCH_ZERO, "reading", LOG_DEBUG, LD_NET);
+ if (tor_tls_got_excess_renegotiations(tls)) {
+ log_info(LD_NET, "Detected excess renegotiation from %s!", ADDR(tls));
+
+ return TOR_TLS_ERROR_MISC;
+ }
+
#ifdef V2_HANDSHAKE_SERVER
if (tls->got_renegotiate) {
tor_assert(tls->server_handshake_count == 2);
@@ -1617,14 +1634,6 @@ tor_tls_read(tor_tls_t *tls, char *cp, size_t len)
tls->got_renegotiate = 0;
return r;
- } else if (tls->server_handshake_count > 2) {
- /* If we get more than 2 handshakes, it means that our peer is
- trying to re-renegotiate. Return an error. */
- tor_assert(tls->server_handshake_count == 3);
-
- log_info(LD_NET, "Detected excess renegotiation from %s!", ADDR(tls));
-
- return TOR_TLS_ERROR_MISC;
}
#endif
@@ -1664,6 +1673,13 @@ tor_tls_write(tor_tls_t *tls, const char *cp, size_t n)
}
r = SSL_write(tls->ssl, cp, (int)n);
err = tor_tls_get_error(tls, r, 0, "writing", LOG_INFO, LD_NET);
+
+ if (tor_tls_got_excess_renegotiations(tls)) {
+ log_info(LD_NET, "Detected excess renegotiation from %s!", ADDR(tls));
+
+ return TOR_TLS_ERROR_MISC;
+ }
+
if (err == TOR_TLS_DONE) {
return r;
}