1 files changed, 26 insertions, 14 deletions

diff --git a/src/openvpn/tls_crypt.c b/src/openvpn/tls_crypt.c
index e13bb4e..403060d 100644
--- a/src/openvpn/tls_crypt.c
+++ b/src/openvpn/tls_crypt.c
@@ -35,35 +35,47 @@
 
 #include "tls_crypt.h"
 
-int
-tls_crypt_buf_overhead(void)
-{
-    return packet_id_size(true) + TLS_CRYPT_TAG_SIZE + TLS_CRYPT_BLOCK_SIZE;
-}
-
-void
-tls_crypt_init_key(struct key_ctx_bi *key, const char *key_file,
-                   const char *key_inline, bool tls_server)
+static struct key_type
+tls_crypt_kt(void)
 {
-    const int key_direction = tls_server ?
-                              KEY_DIRECTION_NORMAL : KEY_DIRECTION_INVERSE;
-
     struct key_type kt;
     kt.cipher = cipher_kt_get("AES-256-CTR");
     kt.digest = md_kt_get("SHA256");
 
     if (!kt.cipher)
     {
-        msg(M_FATAL, "ERROR: --tls-crypt requires AES-256-CTR support.");
+        msg(M_WARN, "ERROR: --tls-crypt requires AES-256-CTR support.");
+        return (struct key_type) { 0 };
     }
     if (!kt.digest)
     {
-        msg(M_FATAL, "ERROR: --tls-crypt requires HMAC-SHA-256 support.");
+        msg(M_WARN, "ERROR: --tls-crypt requires HMAC-SHA-256 support.");
+        return (struct key_type) { 0 };
     }
 
     kt.cipher_length = cipher_kt_key_size(kt.cipher);
     kt.hmac_length = md_kt_size(kt.digest);
 
+    return kt;
+}
+
+int
+tls_crypt_buf_overhead(void)
+{
+    return packet_id_size(true) + TLS_CRYPT_TAG_SIZE + TLS_CRYPT_BLOCK_SIZE;
+}
+
+void
+tls_crypt_init_key(struct key_ctx_bi *key, const char *key_file,
+                   const char *key_inline, bool tls_server)
+{
+    const int key_direction = tls_server ?
+                              KEY_DIRECTION_NORMAL : KEY_DIRECTION_INVERSE;
+    struct key_type kt = tls_crypt_kt();
+    if (!kt.cipher || !kt.digest)
+    {
+        msg (M_FATAL, "ERROR: --tls-crypt not supported");
+    }
     crypto_read_openvpn_key(&kt, key, key_file, key_inline, key_direction,
                             "Control Channel Encryption", "tls-crypt");
 }