Add --insecure-skip-verify flag (#40)

README.md

@@ -56,6 +56,7 @@ Usage:
 
 Flags:
   -h, --help                      help for query
+  -k, --insecure-skip-verify      allow insecure server connections (e.g. self-signed TLS certificates)
       --resolver-addr string      address of a DNS resolver to use for resolving DoH server names (e.g. 8.8.8.8:53)
       --resolver-network string   protocol to use for resolving DoH server names (e.g. udp, tcp) (default "udp")
       --retry-max int             maximum number of retries for each query (default 10)

internal/cli/command_query.go

@@ -2,6 +2,7 @@ package cli
 
 import (
 	"context"
+	"crypto/tls"
 	"encoding/json"
 	"fmt"
 	"net"
@@ -22,7 +23,8 @@ type result struct {
 	Resp   *dj.Response `json:"resp"`
 }
 
-func newClient(retryMax int) (*http.Client, error) {
+// newHTTPClient returns a new HTTP client, or an error if one occurs.
+func newHTTPClient(retryMax int, insecureSkipVerify bool) (*http.Client, error) {
 	retryClient := retryablehttp.NewClient()
 
 	retryClient.RetryMax = retryMax
@@ -31,6 +33,16 @@ func newClient(retryMax int) (*http.Client, error) {
 
 	retryClient.Logger = nil // TODO: consider logger
 
+	if insecureSkipVerify {
+		transport := cleanhttp.DefaultTransport()
+
+		transport.TLSClientConfig = &tls.Config{
+			InsecureSkipVerify: true,
+		}
+
+		retryClient.HTTPClient.Transport = transport
+	}
+
 	retryClient.CheckRetry = func(ctx context.Context, resp *http.Response, err error) (bool, error) {
 		return retryablehttp.DefaultRetryPolicy(ctx, resp, err)
 	}
@@ -76,7 +88,12 @@ which can be piped to other commands (e.g. jq) or redirected to a file.`,
 			return fmt.Errorf("invalid retry max: %w", err)
 		}
 
-		httpClient, err := newClient(retryMax)
+		insecureSkipVerify, err := cmd.Flags().GetBool("insecure-skip-verify")
+		if err != nil {
+			return fmt.Errorf("invalid insecure skip verify: %w", err)
+		}
+
+		httpClient, err := newHTTPClient(retryMax, insecureSkipVerify)
 		if err != nil {
 			return fmt.Errorf("error creating http client: %w", err)
 		}
@@ -172,6 +189,7 @@ func init() {
 	CommandQuery.Flags().String("resolver-addr", "", "address of a DNS resolver to use for resolving DoH server names (e.g. 8.8.8.8:53)")
 	CommandQuery.Flags().String("resolver-network", "udp", "protocol to use for resolving DoH server names (e.g. udp, tcp)")
 	CommandQuery.Flags().Int("retry-max", 10, "maximum number of retries for each query")
+	CommandQuery.Flags().BoolP("insecure-skip-verify", "k", false, "allow insecure server connections (e.g. self-signed TLS certificates)")
 
 	CommandRoot.AddCommand(CommandQuery)
 }

internal/cli/command_test.go

@@ -3,9 +3,14 @@ package cli_test
 import (
 	"bytes"
 	"io"
+	"net"
+	"net/http"
+	"net/http/httptest"
 	"testing"
 
+	"github.com/miekg/dns"
 	"github.com/picatz/doh/internal/cli"
+	"github.com/picatz/doh/pkg/doh"
 )
 
 func testCommand(t *testing.T, args ...string) io.Reader {
@@ -46,7 +51,7 @@ func TestCommand(t *testing.T) {
 			},
 		},
 		{
-			name: "google.com",
+			name: "query google.com",
 			args: []string{"query", "google.com"},
 			check: func(t *testing.T, output io.Reader) {
 				b, err := io.ReadAll(output)
@@ -62,7 +67,7 @@ func TestCommand(t *testing.T) {
 			},
 		},
 		{
-			name: "cloudflare.com",
+			name: "query cloudflare.com",
 			args: []string{"query", "cloudflare.com"},
 			check: func(t *testing.T, output io.Reader) {
 				b, err := io.ReadAll(output)
@@ -87,3 +92,39 @@ func TestCommand(t *testing.T) {
 		})
 	}
 }
+
+func TestCommand_Query_InsecureSkipVerify(t *testing.T) {
+	mux := doh.NewServerMux(func(w http.ResponseWriter, httpReq *http.Request, dnsReq *dns.Msg) (*dns.Msg, error) {
+		dnsResp := new(dns.Msg)
+		dnsResp.SetReply(dnsReq)
+		dnsResp.Answer = append(dnsResp.Answer, &dns.A{
+			Hdr: dns.RR_Header{
+				Name:   dnsReq.Question[0].Name,
+				Rrtype: dns.TypeA,
+				Class:  dns.ClassINET,
+				Ttl:    300,
+			},
+			A: net.ParseIP("8.8.8.8"),
+		})
+
+		return dnsResp, nil
+	})
+
+	server := httptest.NewTLSServer(mux)
+	t.Cleanup(server.Close)
+
+	dohServerURL := server.URL + "/dns-query"
+
+	output := testCommand(t, "query", "google.com", "--insecure-skip-verify", "--servers", dohServerURL)
+
+	b, err := io.ReadAll(output)
+	if err != nil {
+		t.Fatal(err)
+	}
+
+	if len(b) == 0 {
+		t.Fatal("got no output for known domain")
+	}
+
+	t.Log(string(b))
+}