feat: allow wildcard domains in config (#42)

* feat: allow wildcard domains in config

* chore: rename file `loader.go` to `reader.go`

cmd/geoblock/main.go

@@ -2,6 +2,7 @@
 package main
 
 import (
+	"bytes"
 	"os"
 	"time"
 
@@ -51,6 +52,15 @@ func autoUpdate(resolver *iprange.Resolver) {
 	}
 }
 
+// loadConfig reads the configuration file from the given path and returns it.
+func loadConfig(path string) (*config.Configuration, error) {
+	file, err := os.ReadFile(path) // #nosec G304
+	if err != nil {
+		return nil, err
+	}
+	return config.ReadConfig(bytes.NewReader(file))
+}
+
 // hasChanged returns true if the two file infos are different. It only checks
 // the size and the modification time.
 func hasChanged(a, b os.FileInfo) bool {
@@ -78,7 +88,7 @@ func autoReload(engine *rules.Engine, path string) {
 		}
 		prevStat = stat
 
-		cfg, err := config.LoadConfig(path)
+		cfg, err := loadConfig(path)
 		if err != nil {
 			log.Errorf("Cannot read configuration file: %v", err)
 			continue
@@ -110,7 +120,7 @@ func main() {
 	configureLogger(options.logLevel)
 
 	log.Info("Loading configuration file")
-	cfg, err := config.LoadConfig(options.configPath)
+	cfg, err := loadConfig(options.configPath)
 	if err != nil {
 		log.Fatalf("Cannot read configuration file: %v", err)
 	}

pkg/config/loader.go → pkg/config/reader.go

@@ -3,12 +3,27 @@
 package config
 
 import (
-	"os"
+	"io"
+	"regexp"
 
 	"github.com/go-playground/validator/v10"
 	"gopkg.in/yaml.v3"
 )
 
+// DomainNameRegex matches a valid domain name as per RFC 1035. It also allows
+// labels to be a single `*` wildcard.
+var domainNameRegex = regexp.MustCompile(
+	`^(\*|[a-zA-Z0-9]([a-zA-Z0-9-]{0,61}[a-zA-Z0-9])?)(\.(\*|[a-zA-Z0-9]([a-zA-Z0-9-]{0,61}[a-zA-Z0-9])?))*$`,
+)
+
+func isDomainNameField(field validator.FieldLevel) bool {
+	domain, ok := field.Field().Interface().(string)
+	if !ok {
+		return false
+	}
+	return domainNameRegex.MatchString(domain)
+}
+
 // isCIDRField checks if the value of the given field is a valid CIDR.
 func isCIDRField(field validator.FieldLevel) bool {
 	cidr, ok := field.Field().Interface().(CIDR)
@@ -26,7 +41,8 @@ func read(data []byte) (*Configuration, error) {
 	}
 
 	validate := validator.New()
-	validate.RegisterValidation("cidr", isCIDRField) // #nosec G104
+	validate.RegisterValidation("cidr", isCIDRField)         // #nosec G104
+	validate.RegisterValidation("domain", isDomainNameField) // #nosec G104
 
 	if err := validate.Struct(config); err != nil {
 		return nil, err
@@ -35,9 +51,9 @@ func read(data []byte) (*Configuration, error) {
 	return &config, nil
 }
 
-// LoadConfig reads the configuration from the given file.
-func LoadConfig(filename string) (*Configuration, error) {
-	data, err := os.ReadFile(filename) // #nosec G304
+// ReadConfig reads the configuration from the given reader and returns it.
+func ReadConfig(reader io.Reader) (*Configuration, error) {
+	data, err := io.ReadAll(reader)
 	if err != nil {
 		return nil, err
 	}

pkg/config/reader_test.go

@@ -0,0 +1,217 @@
+package config_test
+
+import (
+	"errors"
+	"net"
+	"reflect"
+	"strings"
+	"testing"
+
+	"github.com/danroc/geoblock/pkg/config"
+)
+
+const validConfig = `
+access_control:
+  default_policy: allow
+  rules:
+    - networks:
+        - "10.0.0.0/8"
+        - "127.0.0.0/8"
+      domains:
+        - "example.com"
+        - "*.example.com"
+      methods:
+        - GET
+        - POST
+      countries:
+        - US
+        - FR
+      autonomous_systems:
+        - 1234
+        - 5678
+      policy: allow
+
+    - policy: deny
+`
+
+const invalidLeadingDot = `
+access_control:
+  default_policy: allow
+  rules:
+    - domains:
+      - ".example.com"
+    policy: allow
+`
+
+const invalidWildcardLocation = `
+access_control:
+  default_policy: allow
+  rules:
+    - domains:
+      - "*example.com"
+    policy: allow
+`
+
+const invalidDomainChar = `
+access_control:
+  default_policy: allow
+  rules:
+    - domains:
+      - "example?.com"
+    policy: allow
+`
+
+const invalidLeadingDash = `
+access_control:
+  default_policy: allow
+  rules:
+    - domains:
+      - "-example.com"
+    policy: allow
+`
+
+const invalidTrailingDash = `
+access_control:
+  default_policy: allow
+  rules:
+    - domains:
+      - "example-.com"
+    policy: allow
+`
+
+const invalidDomainString = `
+access_control:
+  default_policy: allow
+  rules:
+    - domains:
+      - false
+    policy: allow
+`
+
+const invalidNetworkString = `
+access_control:
+  default_policy: allow
+  rules:
+    - networks:
+        - "invalid"
+      policy: allow
+`
+
+const invalidNetworkNumber = `
+access_control:
+  default_policy: allow
+  rules:
+    - networks:
+        - 10
+      policy: allow
+`
+
+const invalidNetworkRange = `
+access_control:
+  default_policy: allow
+  rules:
+    - networks:
+        - 300.300.300.300/50
+      policy: allow
+`
+
+func TestReadConfigValid(t *testing.T) {
+	tests := []struct {
+		name     string
+		data     string
+		expected *config.Configuration
+	}{
+		{
+			"valid configuration",
+			validConfig,
+			&config.Configuration{
+				AccessControl: config.AccessControl{
+					DefaultPolicy: "allow",
+					Rules: []config.AccessControlRule{
+						{
+							Policy: "allow",
+							Networks: []config.CIDR{
+								{
+									IPNet: &net.IPNet{
+										IP:   net.IP{10, 0, 0, 0},
+										Mask: net.CIDRMask(8, 32),
+									},
+								},
+								{
+									IPNet: &net.IPNet{
+										IP:   net.IP{127, 0, 0, 0},
+										Mask: net.CIDRMask(8, 32),
+									},
+								},
+							},
+							Domains: []string{
+								"example.com",
+								"*.example.com",
+							},
+							Methods:           []string{"GET", "POST"},
+							Countries:         []string{"US", "FR"},
+							AutonomousSystems: []uint32{1234, 5678},
+						},
+						{
+							Policy:            "deny",
+							Networks:          nil,
+							Domains:           nil,
+							Methods:           nil,
+							Countries:         nil,
+							AutonomousSystems: nil,
+						},
+					},
+				},
+			},
+		},
+	}
+
+	for _, test := range tests {
+		reader := strings.NewReader(test.data)
+		cfg, err := config.ReadConfig(reader)
+		if err != nil {
+			t.Errorf("%s: unexpected error: %v", test.name, err)
+		}
+		if !reflect.DeepEqual(*cfg, *test.expected) {
+			t.Errorf("%s: expected %v, got %v", test.name, test.expected, cfg)
+		}
+	}
+}
+
+func TestReadConfigErr(t *testing.T) {
+	tests := []struct {
+		name string
+		data string
+	}{
+		{"invalid leading dot", invalidLeadingDot},
+		{"invalid wildcard location", invalidWildcardLocation},
+		{"invalid domain character", invalidDomainChar},
+		{"invalid leading dash", invalidLeadingDash},
+		{"invalid trailing dash", invalidTrailingDash},
+		{"invalid network string", invalidNetworkString},
+		{"invalid network number", invalidNetworkNumber},
+		{"invalid network range", invalidNetworkRange},
+		{"invalid domain string", invalidDomainString},
+	}
+
+	for _, test := range tests {
+		reader := strings.NewReader(test.data)
+		_, err := config.ReadConfig(reader)
+		if err == nil {
+			t.Errorf("%s: expected an error but got nil", test.name)
+		}
+	}
+}
+
+type errReader struct{}
+
+func (r *errReader) Read(p []byte) (n int, err error) {
+	return 0, errors.New("read error")
+}
+
+func TestReadConfigErrReader(t *testing.T) {
+	_, err := config.ReadConfig(&errReader{})
+	if err == nil {
+		t.Error("expected an error but got nil")
+	}
+}

pkg/config/schema.go

@@ -33,7 +33,7 @@ func (n *CIDR) UnmarshalYAML(unmarshal func(interface{}) error) error {
 type AccessControlRule struct {
 	Policy            string   `yaml:"policy"                       validate:"required,oneof=allow deny"`
 	Networks          []CIDR   `yaml:"networks,omitempty"           validate:"dive,cidr"`
-	Domains           []string `yaml:"domains,omitempty"            validate:"dive,fqdn"`
+	Domains           []string `yaml:"domains,omitempty"            validate:"dive,domain"`
 	Methods           []string `yaml:"methods,omitempty"            validate:"dive,oneof=GET HEAD POST PUT DELETE PATCH"`
 	Countries         []string `yaml:"countries,omitempty"          validate:"dive,iso3166_1_alpha2"`
 	AutonomousSystems []uint32 `yaml:"autonomous_systems,omitempty" validate:"dive,numeric"`