From cf10ce1b683f8a25f8e920753f3720e97dd1549f Mon Sep 17 00:00:00 2001
From: Miroslav Lichvar <mlichvar@redhat.com>
Date: Wed, 3 Jun 2020 11:03:00 +0200
Subject: [PATCH] nts: allow missing SIV support

When compiled with NTS support, don't require a SIV cipher to be always
supported (e.g. due to a different version of a library used for
building). Handle this case with a fatal message instead of crash.
Also, check the support early in the client unit test to prevent a hang.
---
 nts_ke_server.c            | 7 +++++--
 nts_ntp_server.c           | 2 ++
 test/unit/nts_ntp_client.c | 2 ++
 3 files changed, 9 insertions(+), 2 deletions(-)

diff --git a/nts_ke_server.c b/nts_ke_server.c
index ca3c04b..76bb6a3 100644
--- a/nts_ke_server.c
+++ b/nts_ke_server.c
@@ -433,8 +433,11 @@ generate_key(int index)
     assert(0);
 
   UTI_GetRandomBytesUrandom(server_keys[index].key, key_length);
-  if (!SIV_SetKey(server_keys[index].siv, server_keys[index].key, key_length))
-    assert(0);
+
+  if (!server_keys[index].siv ||
+      !SIV_SetKey(server_keys[index].siv, server_keys[index].key, key_length)) {
+    LOG_FATAL("Could not set SIV key");
+  }
 
   UTI_GetRandomBytes(&server_keys[index].id, sizeof (server_keys[index].id));
 
diff --git a/nts_ntp_server.c b/nts_ntp_server.c
index 6718c5a..f4df796 100644
--- a/nts_ntp_server.c
+++ b/nts_ntp_server.c
@@ -67,6 +67,8 @@ NNS_Initialise(void)
 
   server = Malloc(sizeof (struct NtsServer));
   server->siv = SIV_CreateInstance(SERVER_SIV);
+  if (!server->siv)
+    LOG_FATAL("Could not initialise SIV cipher");
 }
 
 /* ================================================== */
diff --git a/test/unit/nts_ntp_client.c b/test/unit/nts_ntp_client.c
index ad76fc8..448ff7e 100644
--- a/test/unit/nts_ntp_client.c
+++ b/test/unit/nts_ntp_client.c
@@ -200,6 +200,8 @@ test_unit(void)
   IPAddr ip_addr;
   int i, j, prev_num_cookies, valid;
 
+  TEST_CHECK(SIV_GetKeyLength(AEAD_AES_SIV_CMAC_256) > 0);
+
   SCK_GetLoopbackIPAddress(AF_INET, &addr.ip_addr);
   addr.port = 0;