external/conscrypt: allow server-initiated renegotiations.

BoringSSL disables server-initiated renegotiations by default. However,
it's unclear what the impact of this will be. On the other hand,
rejecting renegotiations certainly makes things simplier.

(cherry picked from commit ed628f94)

Bug: 23189319
Change-Id: I0cd3f04838c0afea665a88d4f0cd0a16c1e811de

src/main/java/org/conscrypt/NativeCrypto.java

@@ -1011,6 +1011,9 @@ public final class NativeCrypto {
     public static native void SSL_set_session_creation_enabled(
             long sslNativePointer, boolean creationEnabled) throws SSLException;
 
+    public static native void SSL_set_reject_peer_renegotiations(
+            long sslNativePointer, boolean renegotiationRejected) throws SSLException;
+
     public static native void SSL_set_tlsext_host_name(long sslNativePointer, String hostname)
             throws SSLException;
     public static native String SSL_get_servername(long sslNativePointer);

src/main/java/org/conscrypt/OpenSSLSocketImpl.java

@@ -293,6 +293,11 @@ public class OpenSSLSocketImpl
                         enableSessionCreation);
             }
 
+            // Allow servers to trigger renegotiation. Some inadvisable server
+            // configurations cause them to attempt to renegotiate during
+            // certain protocols.
+            NativeCrypto.SSL_set_reject_peer_renegotiations(sslNativePointer, false);
+
             final OpenSSLSessionImpl sessionToReuse = sslParameters.getSessionToReuse(
                     sslNativePointer, getHostname(), getPort());
             sslParameters.setSSLParameters(sslCtxNativePointer, sslNativePointer, this, this,

src/main/native/org_conscrypt_NativeCrypto.cpp

@@ -8895,6 +8895,25 @@ static void NativeCrypto_SSL_set_session_creation_enabled(JNIEnv* env, jclass,
 #endif
 }
 
+static void NativeCrypto_SSL_set_reject_peer_renegotiations(JNIEnv* env, jclass,
+        jlong ssl_address, jboolean reject_renegotiations)
+{
+    SSL* ssl = to_SSL(env, ssl_address, true);
+    JNI_TRACE("ssl=%p NativeCrypto_SSL_set_reject_peer_renegotiations reject_renegotiations=%d",
+              ssl, reject_renegotiations);
+    if (ssl == NULL) {
+        return;
+    }
+
+#if defined(OPENSSL_IS_BORINGSSL)
+    SSL_set_reject_peer_renegotiations(ssl, reject_renegotiations);
+#else
+    (void) reject_renegotiations;
+    /* OpenSSL doesn't support this call and accepts renegotiation requests by
+     * default. */
+#endif
+}
+
 static void NativeCrypto_SSL_set_tlsext_host_name(JNIEnv* env, jclass,
         jlong ssl_address, jstring hostname)
 {
@@ -10825,6 +10844,7 @@ static JNINativeMethod sNativeCryptoMethods[] = {
     NATIVE_METHOD(NativeCrypto, SSL_set_verify, "(JI)V"),
     NATIVE_METHOD(NativeCrypto, SSL_set_session, "(JJ)V"),
     NATIVE_METHOD(NativeCrypto, SSL_set_session_creation_enabled, "(JZ)V"),
+    NATIVE_METHOD(NativeCrypto, SSL_set_reject_peer_renegotiations, "(JZ)V"),
     NATIVE_METHOD(NativeCrypto, SSL_set_tlsext_host_name, "(JLjava/lang/String;)V"),
     NATIVE_METHOD(NativeCrypto, SSL_get_servername, "(J)Ljava/lang/String;"),
     NATIVE_METHOD(NativeCrypto, SSL_do_handshake, "(J" FILE_DESCRIPTOR SSL_CALLBACKS "IZ[B[B)J"),