From 8f6f04eb21276f28b81695dd0d3df57c7b8f43e4 Mon Sep 17 00:00:00 2001
From: Aki Tuomi <aki.tuomi@open-xchange.com>
Date: Mon, 29 Jul 2019 16:08:07 +0300
Subject: [PATCH] lib-ssl-iostream: Support TLSv1.3 ciphersuites

---
 m4/ssl.m4                                       |  3 +++
 src/lib-ssl-iostream/iostream-openssl-context.c |  8 ++++++++
 src/lib-ssl-iostream/iostream-openssl.c         | 11 +++++++++++
 src/lib-ssl-iostream/iostream-ssl.c             |  1 +
 src/lib-ssl-iostream/iostream-ssl.h             |  1 +
 src/lib-ssl-iostream/test-iostream-ssl.c        |  2 ++
 6 files changed, 26 insertions(+)

diff --git a/m4/ssl.m4 b/m4/ssl.m4
index faf9cb1c4e..b9329a642e 100644
--- a/m4/ssl.m4
+++ b/m4/ssl.m4
@@ -212,6 +212,9 @@ AC_DEFUN([DOVECOT_SSL], [
       AC_CHECK_LIB(ssl, EVP_PKEY_get0_RSA, [
         AC_DEFINE(HAVE_EVP_PKEY_get0,, [Build with EVP_PKEY_get0_*() support])
       ],, $SSL_LIBS)
+      AC_CHECK_LIB(ssl, SSL_CTX_set_ciphersuites, [
+        AC_DEFINE(HAVE_SSL_CTX_SET_CIPHERSUITES,, [Build with SSL_CTX_set_ciphersuites() support])
+      ],, $SSL_LIBS)
       AC_CHECK_LIB(ssl, [EVP_PKEY_CTX_new_id], [have_evp_pkey_ctx_new_id="yes"],, $SSL_LIBS)
       AC_CHECK_LIB(ssl, [EC_KEY_new], [have_ec_key_new="yes"],, $SSL_LIBS)
       if test "$have_evp_pkey_ctx_new_id" = "yes" && test "$have_ec_key_new" = "yes"; then
diff --git a/src/lib-ssl-iostream/iostream-openssl-context.c b/src/lib-ssl-iostream/iostream-openssl-context.c
index c4a614f65b..3824ddda01 100644
--- a/src/lib-ssl-iostream/iostream-openssl-context.c
+++ b/src/lib-ssl-iostream/iostream-openssl-context.c
@@ -387,6 +387,14 @@ ssl_iostream_context_set(struct ssl_iostream_context *ctx,
 					   set->curve_list);
 		return -1;
 	}
+#endif
+#ifdef HAVE_SSL_CTX_SET_CIPHERSUITES
+	if (set->ciphersuites != NULL &&
+	    SSL_CTX_set_ciphersuites(ctx->ssl_ctx, set->ciphersuites) == 0) {
+		*error_r = t_strdup_printf("Can't set ciphersuites to '%s': %s",
+			set->cipher_list, openssl_iostream_error());
+		return -1;
+	}
 #endif
 	if (set->prefer_server_ciphers) {
 		SSL_CTX_set_options(ctx->ssl_ctx,
diff --git a/src/lib-ssl-iostream/iostream-openssl.c b/src/lib-ssl-iostream/iostream-openssl.c
index 5b87ee68d6..5b2d8c7a8a 100644
--- a/src/lib-ssl-iostream/iostream-openssl.c
+++ b/src/lib-ssl-iostream/iostream-openssl.c
@@ -180,6 +180,17 @@ openssl_iostream_set(struct ssl_iostream *ssl_io,
 			return -1;
 		}
 	}
+#endif
+#ifdef HAVE_SSL_CTX_SET_CIPHERSUITES
+        if (set->ciphersuites != NULL &&
+	    strcmp(ctx_set->ciphersuites, set->ciphersuites) != 0) {
+		if (SSL_set_ciphersuites(ssl_io->ssl, set->ciphersuites) == 0) {
+			*error_r = t_strdup_printf(
+				"Can't set ciphersuites to '%s': %s",
+				set->ciphersuites, openssl_iostream_error());
+			return -1;
+		}
+	}
 #endif
 	if (set->prefer_server_ciphers)
 		SSL_set_options(ssl_io->ssl, SSL_OP_CIPHER_SERVER_PREFERENCE);
diff --git a/src/lib-ssl-iostream/iostream-ssl.c b/src/lib-ssl-iostream/iostream-ssl.c
index f857ec9f88..f62c80d37f 100644
--- a/src/lib-ssl-iostream/iostream-ssl.c
+++ b/src/lib-ssl-iostream/iostream-ssl.c
@@ -8,6 +8,7 @@
 static const size_t ssl_iostream_settings_string_offsets[] = {
 	OFFSET(min_protocol),
 	OFFSET(cipher_list),
+	OFFSET(ciphersuites),
 	OFFSET(curve_list),
 	OFFSET(ca),
 	OFFSET(ca_file),
diff --git a/src/lib-ssl-iostream/iostream-ssl.h b/src/lib-ssl-iostream/iostream-ssl.h
index 7ef4ef003b..322448691f 100644
--- a/src/lib-ssl-iostream/iostream-ssl.h
+++ b/src/lib-ssl-iostream/iostream-ssl.h
@@ -16,6 +16,7 @@ struct ssl_iostream_settings {
 	   ssl_iostream_settings_drop_stream_only() */
 	const char *min_protocol; /* both */
 	const char *cipher_list; /* both */
+	const char *ciphersuites; /* both, TLSv1.3 only */
 	const char *curve_list; /* both */
 	const char *ca, *ca_file, *ca_dir; /* context-only */
 	/* alternative cert is for providing certificate using
diff --git a/src/lib-ssl-iostream/test-iostream-ssl.c b/src/lib-ssl-iostream/test-iostream-ssl.c
index c3418bfcc5..a87c97f7c2 100644
--- a/src/lib-ssl-iostream/test-iostream-ssl.c
+++ b/src/lib-ssl-iostream/test-iostream-ssl.c
@@ -327,6 +327,8 @@ static void test_iostream_ssl_handshake(void)
 	ssl_iostream_test_settings_client(&client_set);
 	server_set.cipher_list = "ECDSA";
 	client_set.cipher_list = "RSA";
+	server_set.ciphersuites = "TLS_CHACHA20_POLY1305_SHA256";
+	client_set.ciphersuites = "TLS_AES_128_CCM_SHA256";
 	client_set.prefer_server_ciphers = TRUE;
 	client_set.verify_remote_cert = TRUE;
 	test_expect_error_string("client(127.0.0.1): SSL certificate not received");
-- 
2.47.3