ssl: Fix conversion warning in tls_prepend_opcode_v1

Document assumption with ASSERT.

Change-Id: I34584f695ddca3b3e1f2bbcb4380ac91b09c1c8d
Signed-off-by: Frank Lichtenheld <frank@lichtenheld.com>
Acked-by: Gert Doering <gert@greenie.muc.de>
Gerrit URL: https://gerrit.openvpn.net/c/openvpn/+/1298
Message-Id: <20251116183336.11447-1-gert@greenie.muc.de>
URL: https://www.mail-archive.com/openvpn-devel@lists.sourceforge.net/msg34480.html
Signed-off-by: Gert Doering <gert@greenie.muc.de>

diff --git a/src/openvpn/ssl.c b/src/openvpn/ssl.c
index 896fd651e9238f050535687f1a4215f31117959b..2d24f5e2e2b40c39c2c9de028a292657cfb990f8 100644 (file)
--- a/src/openvpn/ssl.c
+++ b/src/openvpn/ssl.c
@@ -3962,24 +3962,24 @@ tls_pre_encrypt(struct tls_multi *multi, struct buffer *buf, struct crypto_optio
     }
 }
 
+#if defined(__GNUC__) || defined(__clang__)
+#pragma GCC diagnostic pop
+#endif
+
 void
 tls_prepend_opcode_v1(const struct tls_multi *multi, struct buffer *buf)
 {
     struct key_state *ks = multi->save_ks;
-    uint8_t op;
 
     msg(D_TLS_DEBUG, __func__);
 
     ASSERT(ks);
+    ASSERT(ks->key_id <= P_KEY_ID_MASK);
 
-    op = (P_DATA_V1 << P_OPCODE_SHIFT) | ks->key_id;
+    uint8_t op = (P_DATA_V1 << P_OPCODE_SHIFT) | (uint8_t)ks->key_id;
     ASSERT(buf_write_prepend(buf, &op, 1));
 }
 
-#if defined(__GNUC__) || defined(__clang__)
-#pragma GCC diagnostic pop
-#endif
-
 void
 tls_prepend_opcode_v2(const struct tls_multi *multi, struct buffer *buf)
 {