TUN-7628: Correct Host parsing for Access

Will no longer provide full hostname with path from provided
`--hostname` flag for cloudflared access to the Host header field.
This addresses certain issues caught from a security fix in go
1.19.11 and 1.20.6 in the net/http URL parsing.

cmd/cloudflared/access/validation_test.go

@@ -0,0 +1,80 @@
+package access
+
+import (
+	"fmt"
+	"testing"
+
+	"github.com/stretchr/testify/assert"
+)
+
+func TestParseRequestHeaders(t *testing.T) {
+	values := parseRequestHeaders([]string{"client: value", "secret: safe-value", "trash", "cf-trace-id: 000:000:0:1:asd"})
+	assert.Len(t, values, 3)
+	assert.Equal(t, "value", values.Get("client"))
+	assert.Equal(t, "safe-value", values.Get("secret"))
+	assert.Equal(t, "000:000:0:1:asd", values.Get("cf-trace-id"))
+}
+
+func TestParseURL(t *testing.T) {
+	schemes := []string{
+		"http://",
+		"https://",
+		"",
+	}
+	hosts := []struct {
+		input    string
+		expected string
+	}{
+		{"localhost", "localhost"},
+		{"127.0.0.1", "127.0.0.1"},
+		{"127.0.0.1:9090", "127.0.0.1:9090"},
+		{"::1", "::1"},
+		{"::1:8080", "::1:8080"},
+		{"[::1]", "[::1]"},
+		{"[::1]:8080", "[::1]:8080"},
+		{":8080", ":8080"},
+		{"example.com", "example.com"},
+		{"hello.example.com", "hello.example.com"},
+		{"bücher.example.com", "xn--bcher-kva.example.com"},
+	}
+	paths := []string{
+		"",
+		"/test",
+		"/example.com?qwe=123",
+	}
+	for i, scheme := range schemes {
+		for j, host := range hosts {
+			for k, path := range paths {
+				t.Run(fmt.Sprintf("%d_%d_%d", i, j, k), func(t *testing.T) {
+					input := fmt.Sprintf("%s%s%s", scheme, host.input, path)
+					expected := fmt.Sprintf("%s%s%s", "https://", host.expected, path)
+					url, err := parseURL(input)
+					assert.NoError(t, err, "input: %s\texpected: %s", input, expected)
+					assert.Equal(t, expected, url.String())
+					assert.Equal(t, host.expected, url.Host)
+					assert.Equal(t, "https", url.Scheme)
+				})
+			}
+		}
+	}
+
+	t.Run("no input", func(t *testing.T) {
+		_, err := parseURL("")
+		assert.ErrorContains(t, err, "no input provided")
+	})
+
+	t.Run("missing host", func(t *testing.T) {
+		_, err := parseURL("https:///host")
+		assert.ErrorContains(t, err, "failed to parse Host")
+	})
+
+	t.Run("invalid path only", func(t *testing.T) {
+		_, err := parseURL("/host")
+		assert.ErrorContains(t, err, "failed to parse Host")
+	})
+
+	t.Run("invalid parse URL", func(t *testing.T) {
+		_, err := parseURL("https://host\\host")
+		assert.ErrorContains(t, err, "failed to parse as URL")
+	})
+}