validate args before deleting proxy defaults (#14290)

* validate args before deleting proxy defaults

* add changelog

* validate name when normalizing proxy defaults

* add test for proxyConfigEntry

* add comments

.changelog/14290.txt

@@ -0,0 +1,3 @@
+```release-note:bugfix
+envoy: validate name before deleting proxy default configurations. 
+```

agent/structs/config_entry.go

@@ -3,12 +3,13 @@ package structs
 import (
 	"errors"
 	"fmt"
-	"github.com/miekg/dns"
 	"net"
 	"strconv"
 	"strings"
 	"time"
 
+	"github.com/miekg/dns"
+
 	"github.com/hashicorp/go-multierror"
 	"github.com/mitchellh/hashstructure"
 	"github.com/mitchellh/mapstructure"
@@ -362,6 +363,13 @@ func (e *ProxyConfigEntry) Normalize() error {
 	}
 
 	e.Kind = ProxyDefaults
+
+	// proxy default config only accepts global configs
+	// this check is replicated in normalize() and validate(),
+	// since validate is not called by all the endpoints (e.g., delete)
+	if e.Name != "" && e.Name != ProxyConfigGlobal {
+		return fmt.Errorf("invalid name (%q), only %q is supported", e.Name, ProxyConfigGlobal)
+	}
 	e.Name = ProxyConfigGlobal
 
 	e.EnterpriseMeta.Normalize()

agent/structs/config_entry_test.go

@@ -2944,6 +2944,27 @@ func TestParseUpstreamConfig(t *testing.T) {
 	}
 }
 
+func TestProxyConfigEntry(t *testing.T) {
+	cases := map[string]configEntryTestcase{
+		"proxy config name provided is not global": {
+			entry: &ProxyConfigEntry{
+				Name: "foo",
+			},
+			normalizeErr: `invalid name ("foo"), only "global" is supported`,
+		},
+		"proxy config has no name": {
+			entry: &ProxyConfigEntry{
+				Name: "",
+			},
+			expected: &ProxyConfigEntry{
+				Name: ProxyConfigGlobal,
+				Kind: ProxyDefaults,
+			},
+		},
+	}
+	testConfigEntryNormalizeAndValidate(t, cases)
+}
+
 func requireContainsLower(t *testing.T, haystack, needle string) {
 	t.Helper()
 	require.Contains(t, strings.ToLower(haystack), strings.ToLower(needle))