descriptor: explicitly disallow wrappers on ct() and blinding keys

Author: jgriffiths

src/ctest/test_descriptor.c

@@ -1609,6 +1609,10 @@ static const struct descriptor_test {
         "descriptor errchk - empty ct()",
         "ct()",
         WALLY_NETWORK_LIQUID, 0, 0, 0, NULL, 0, NULL, ""
+    }, {
+        "descriptor errchk - wrapper on ct()",
+        "v:ct(slip77(slip77_key),elpkh(key_4))",
+        WALLY_NETWORK_LIQUID, 0, 0, 0, NULL, 0, NULL, ""
     }, {
         "descriptor errchk - single child ct()",
         "ct(slip77(slip77_key))",
@@ -1637,6 +1641,10 @@ static const struct descriptor_test {
         "descriptor errchk - invalid blinding key in slip77()",
         "ct(slip77(010101010101010101),elpkh(key_4))",
         WALLY_NETWORK_LIQUID, 0, 0, 0, NULL, 0, NULL, ""
+    }, {
+        "descriptor errchk - wrapper on slip77()",
+        "ct(v:slip77(slip77_key),elpkh(key_4))",
+        WALLY_NETWORK_LIQUID, 0, 0, 0, NULL, 0, NULL, ""
     }, {
         "descriptor errchk - ELIP 150 WIF private key",
         "ct(L3jXxwef3fpB7hcrFozcWgHeJCPSAFiZ1Ji2YJMPxceaGvy3PC1q,elwpkh(03774eec7a3d550d18e9f89414152025b3b0ad6a342b19481f702d843cff06dfc4))#gcy6hcfz",

src/descriptor.c

@@ -1049,7 +1049,7 @@ static int verify_thresh(ms_ctx *ctx, ms_node *node)
 static int verify_ct(ms_ctx *ctx, ms_node *node)
 {
     (void)ctx;
-    if (node->parent)
+    if (node->parent || node->wrapper_str[0])
         return WALLY_EINVAL;
     if (node->child->kind != KIND_DESCRIPTOR_SLIP77 &&
         !(node->child->kind & KIND_KEY) &&
@@ -1084,7 +1084,8 @@ static int verify_slip77(ms_ctx *ctx, ms_node *node)
     if (!node->parent || node->parent->kind != KIND_DESCRIPTOR_CT)
         return WALLY_EINVAL;
     if (node->child->builtin || !(node->child->kind & KIND_RAW) ||
-        node->child->data_len != 32)
+        node->child->data_len != 32 || node->wrapper_str[0])
+
         return WALLY_EINVAL;
     return WALLY_OK;
 }