mw/dnssec: warn when keys don't sign zones (#1011)

fail startup when dnssec middleware has keys configured that can't be
used to sign any of the responses it should sign.

More tests added, including ones that actually trigger setup failures.

middleware/dnssec/setup.go

 package dnssec
 
 import (
+	"fmt"
 	"strconv"
 	"strings"
 
@@ -75,6 +76,22 @@ func dnssecParse(c *caddy.Controller) ([]string, []*DNSKEY, int, error) {
 	for i := range zones {
 		zones[i] = middleware.Host(zones[i]).Normalize()
 	}
+
+	// Check if each keys owner name can actually sign the zones we want them to sign
+	for _, k := range keys {
+		kname := middleware.Name(k.K.Header().Name)
+		ok := false
+		for i := range zones {
+			if kname.Matches(zones[i]) {
+				ok = true
+				break
+			}
+		}
+		if !ok {
+			return zones, keys, capacity, fmt.Errorf("key %s (keyid: %d) can not sign any of the zones", string(kname), k.keytag)
+		}
+	}
+
 	return zones, keys, capacity, nil
 }
 
@@ -87,6 +104,10 @@ func keyParse(c *caddy.Controller) ([]*DNSKEY, error) {
 	value := c.Val()
 	if value == "file" {
 		ks := c.RemainingArgs()
+		if len(ks) == 0 {
+			return nil, c.ArgErr()
+		}
+
 		for _, k := range ks {
 			base := k
 			// Kmiek.nl.+013+26205.key, handle .private or without extension: Kmiek.nl.+013+26205

middleware/dnssec/setup_test.go

 package dnssec
 
 import (
+	"io/ioutil"
+	"os"
 	"strings"
 	"testing"
 
@@ -8,6 +10,15 @@ import (
 )
 
 func TestSetupDnssec(t *testing.T) {
+	if err := ioutil.WriteFile("Kcluster.local.key", []byte(keypub), 0644); err != nil {
+		t.Fatalf("Failed to write pub key file: %s", err)
+	}
+	defer func() { os.Remove("Kcluster.local.key") }()
+	if err := ioutil.WriteFile("Kcluster.local.private", []byte(keypriv), 0644); err != nil {
+		t.Fatalf("Failed to write private key file: %s", err)
+	}
+	defer func() { os.Remove("Kcluster.local.private") }()
+
 	tests := []struct {
 		input              string
 		shouldErr          bool
@@ -16,19 +27,39 @@ func TestSetupDnssec(t *testing.T) {
 		expectedCapacity   int
 		expectedErrContent string
 	}{
+		{`dnssec`, false, nil, nil, defaultCap, ""},
+		{`dnssec example.org`, false, []string{"example.org."}, nil, defaultCap, ""},
+		{`dnssec 10.0.0.0/8`, false, []string{"10.in-addr.arpa."}, nil, defaultCap, ""},
 		{
-			`dnssec`, false, nil, nil, defaultCap, "",
+			`dnssec example.org {
+				cache_capacity 100
+			}`, false, []string{"example.org."}, nil, 100, "",
 		},
 		{
-			`dnssec example.org`, false, []string{"example.org."}, nil, defaultCap, "",
+			`dnssec cluster.local {
+				key file Kcluster.local
+			}`, false, []string{"cluster.local."}, nil, defaultCap, "",
 		},
 		{
-			`dnssec 10.0.0.0/8`, false, []string{"10.in-addr.arpa."}, nil, defaultCap, "",
+			`dnssec example.org cluster.local {
+				key file Kcluster.local
+			}`, false, []string{"example.org.", "cluster.local."}, nil, defaultCap, "",
 		},
+		// fails
 		{
 			`dnssec example.org {
-				cache_capacity 100
-			}`, false, []string{"example.org."}, nil, 100, "",
+				key file Kcluster.local
+			}`, true, []string{"example.org."}, nil, defaultCap, "can not sign any",
+		},
+		{
+			`dnssec example.org {
+				key
+			}`, true, []string{"example.org."}, nil, defaultCap, "argument count",
+		},
+		{
+			`dnssec example.org {
+				key file
+			}`, true, []string{"example.org."}, nil, defaultCap, "argument count",
 		},
 	}
 
@@ -66,3 +97,24 @@ func TestSetupDnssec(t *testing.T) {
 		}
 	}
 }
+
+const keypub = `; This is a zone-signing key, keyid 45330, for cluster.local.
+; Created: 20170901060531 (Fri Sep  1 08:05:31 2017)
+; Publish: 20170901060531 (Fri Sep  1 08:05:31 2017)
+; Activate: 20170901060531 (Fri Sep  1 08:05:31 2017)
+cluster.local. IN DNSKEY 256 3 5 AwEAAcFpDv+Cb23kFJowu+VU++b2N1uEHi6Ll9H0BzLasFOdJjEEclCO q/KlD4682vOMXxJNN8ZwOyiCa7Y0TEYqSwWvhHyn3bHCwuy4I6fss4Wd 7Y9dU+6QTgJ8LimGG40Iizjc9zqoU8Q+q81vIukpYWOHioHoY7hsWBvS RSlzDJk3`
+
+const keypriv = `Private-key-format: v1.3
+Algorithm: 5 (RSASHA1)
+Modulus: wWkO/4JvbeQUmjC75VT75vY3W4QeLouX0fQHMtqwU50mMQRyUI6r8qUPjrza84xfEk03xnA7KIJrtjRMRipLBa+EfKfdscLC7Lgjp+yzhZ3tj11T7pBOAnwuKYYbjQiLONz3OqhTxD6rzW8i6SlhY4eKgehjuGxYG9JFKXMMmTc=
+PublicExponent: AQAB
+PrivateExponent: K5XyZFBPrjMVFX5gCZlyPyVDamNGrfSVXSIiMSqpS96BSdCXtmHAjCj4bZFPwkzi6+vs4tJN8p4ZifEVM0a6qwPZyENBrc2qbsweOXE6l8BaPVWFX30xvVRzGXuNtXxlBXE17zoHty5r5mRyRou1bc2HUS5otdkEjE30RiocQVk=
+Prime1: 7RRFUxaZkVNVH1DaT/SV5Sb8kABB389qLwU++argeDCVf+Wm9BBlTrsz2U6bKlfpaUmYZKtCCd+CVxqzMyuu0w==
+Prime2: 0NiY3d7Fa08IGY9L4TaFc02A721YcDNBBf95BP31qGvwnYsLFM/1xZwaEsIjohg8g+m/GpyIlvNMbK6pywIVjQ==
+Exponent1: XjXO8pype9mMmvwrNNix9DTQ6nxfsQugW30PMHGZ78kGr6NX++bEC0xS50jYWjRDGcbYGzD+9iNujSScD3qNZw==
+Exponent2: wkoOhLIfhUIj7etikyUup2Ld5WAbW15DSrotstg0NrgcQ+Q7reP96BXeJ79WeREFE09cyvv/EjdLzPv81/CbbQ==
+Coefficient: ah4LL0KLTO8kSKHK+X9Ud8grYi94QSNdbX11ge/eFcS/41QhDuZRTAFv4y0+IG+VWd+XzojLsQs+jzLe5GzINg==
+Created: 20170901060531
+Publish: 20170901060531
+Activate: 20170901060531
+`