feat!: fine-grained permissions

README.md

@@ -75,8 +75,10 @@ debug: false
 # Default is '.' (current directory).
 directory: .
 
-# The default modification permissions for users. Default is 'false'.
+# The default permissions for users. This is a case insensitive option. Possible
-modify: true
+# permissions: C (Create), R (Read), U (Update), D (Delete). You can combine multiple
+# permissions. For example, to allow to read and create, set "RC". Default is "R".
+permissions: R
 
 # The default permissions rules for users. Default is none.
 rules: []
@@ -120,19 +122,19 @@ users:
     password: "{env}ENV_PASSWORD"
   - username: basic
     password: basic
-    # Override default modify.
+    # Override default permissions.
-    modify: false
+    permissions: CRUD
     rules:
       # With this rule, the user CANNOT access /some/files.
       - path: /some/file
-        allow: false
+        permissions: none
-      # With this rule, the user CAN modify /public/access.
+      # With this rule, the user CAN create, read, update and delete within /public/access.
       - path: /public/access/
-        modify: true
+        permissions: CRUD
-      # With this rule, the user CAN modify all files ending with .js. It uses
+      # With this rule, the user CAN read and update all files ending with .js. It uses
       # a regular expression.
       - regex: "^.+.js$"
-        modify: true
+        permissions: RU
 ```
 
 ### CORS

lib/config.go

@@ -23,7 +23,7 @@ const (
 )
 
 type Config struct {
-	Permissions `mapstructure:",squash"`
+	UserPermissions `mapstructure:",squash"`
 	Debug           bool
 	Address         string
 	Port            int
@@ -74,7 +74,7 @@ func ParseConfig(filename string, flags *pflag.FlagSet) (*Config, error) {
 
 	// Other defaults
 	v.SetDefault("Directory", ".")
-	v.SetDefault("Modify", false)
+	v.SetDefault("Permissions", "R")
 	v.SetDefault("Debug", false)
 	v.SetDefault("NoSniff", false)
 	v.SetDefault("Log.Format", "console")
@@ -108,8 +108,8 @@ func ParseConfig(filename string, flags *pflag.FlagSet) (*Config, error) {
 			cfg.Users[i].Directory = cfg.Directory
 		}
 
-		if !v.IsSet(fmt.Sprintf("Users.%d.Modify", i)) {
+		if !v.IsSet(fmt.Sprintf("Users.%d.Permissions", i)) {
-			cfg.Users[i].Modify = cfg.Modify
+			cfg.Users[i].Permissions = cfg.Permissions
 		}
 
 		if !v.IsSet(fmt.Sprintf("Users.%d.Rules", i)) {
@@ -153,7 +153,7 @@ func (c *Config) Validate() error {
 		}
 	}
 
-	err = c.Permissions.Validate()
+	err = c.UserPermissions.Validate()
 	if err != nil {
 		return fmt.Errorf("invalid config: %w", err)
 	}

lib/config_test.go

@@ -49,17 +49,25 @@ func TestConfigCascade(t *testing.T) {
 	t.Parallel()
 
 	check := func(t *testing.T, cfg *Config) {
-		require.True(t, cfg.Modify)
+		require.True(t, cfg.Permissions.Read)
+		require.True(t, cfg.Permissions.Create)
+		require.False(t, cfg.Permissions.Delete)
+		require.False(t, cfg.Permissions.Update)
 		require.Equal(t, "/", cfg.Directory)
 		require.Len(t, cfg.Rules, 1)
 
 		require.Len(t, cfg.Users, 2)
-
+		require.True(t, cfg.Users[0].Permissions.Read)
-		require.True(t, cfg.Users[0].Modify)
+		require.True(t, cfg.Users[0].Permissions.Create)
+		require.False(t, cfg.Users[0].Permissions.Delete)
+		require.False(t, cfg.Users[0].Permissions.Update)
 		require.Equal(t, "/", cfg.Users[0].Directory)
 		require.Len(t, cfg.Users[0].Rules, 1)
 
-		require.False(t, cfg.Users[1].Modify)
+		require.True(t, cfg.Users[1].Permissions.Read)
+		require.False(t, cfg.Users[1].Permissions.Create)
+		require.False(t, cfg.Users[1].Permissions.Delete)
+		require.False(t, cfg.Users[1].Permissions.Update)
 		require.Equal(t, "/basic", cfg.Users[1].Directory)
 		require.Len(t, cfg.Users[1].Rules, 0)
 	}
@@ -67,10 +75,10 @@ func TestConfigCascade(t *testing.T) {
 	t.Run("YAML", func(t *testing.T) {
 		content := `
 directory: /
-modify: true
+permissions: CR
 rules:
   - path: /public/access/
-    modify: true
+    permissions: R
 
 users:
   - username: admin
@@ -78,7 +86,7 @@ users:
   - username: basic
     password: basic
     directory: /basic
-    modify: false
+    permissions: R
     rules: []`
 
 		cfg := writeAndParseConfig(t, content, ".yml")
@@ -90,11 +98,11 @@ users:
 	t.Run("JSON", func(t *testing.T) {
 		content := `{
 	"directory": "/",
-	"modify": true,
+	"permissions": "CR",
 	"rules": [
 		{
 			"path": "/public/access/",
-			"modify": true
+			"permissions": "R"
 		}
 	],
 	"users": [
@@ -106,7 +114,7 @@ users:
 			"username": "basic",
 			"password": "basic",
 			"directory": "/basic",
-			"modify": false,
+			"permissions": "R",
 			"rules": []
 		}
 	]
@@ -121,11 +129,11 @@ users:
 	t.Run("`TOML", func(t *testing.T) {
 		content := `
 directory = "/"
-modify = true
+permissions = "CR"
 
 [[rules]]
 path = "/public/access/"
-modify = true
+permissions = "R"
 
 [[users]]
 username = "admin"
@@ -135,7 +143,7 @@ password = "admin"
 username = "basic"
 password = "basic"
 directory = "/basic"
-modify = false
+permissions = "R"
 rules = []
 `
 
@@ -175,12 +183,9 @@ cors:
 func TestConfigRules(t *testing.T) {
 	content := `
 directory: /
-modify: true
 rules:
   - regex: '^.+\.js$'
-    modify: true
+  - path: /public/access/`
-  - path: /public/access/
-    modify: true`
 
 	cfg := writeAndParseConfig(t, content, ".yaml")
 	require.NoError(t, cfg.Validate())
@@ -199,7 +204,7 @@ rules:
 func TestConfigEnv(t *testing.T) {
 	require.NoError(t, os.Setenv("WD_PORT", "1234"))
 	require.NoError(t, os.Setenv("WD_DEBUG", "true"))
-	require.NoError(t, os.Setenv("WD_MODIFY", "true"))
+	require.NoError(t, os.Setenv("WD_PERMISSIONS", "CRUD"))
 	require.NoError(t, os.Setenv("WD_DIRECTORY", "/test"))
 
 	cfg, err := ParseConfig("", nil)
@@ -208,11 +213,14 @@ func TestConfigEnv(t *testing.T) {
 	assert.Equal(t, 1234, cfg.Port)
 	assert.Equal(t, "/test", cfg.Directory)
 	assert.Equal(t, true, cfg.Debug)
-	assert.Equal(t, true, cfg.Modify)
+	require.True(t, cfg.Permissions.Read)
+	require.True(t, cfg.Permissions.Create)
+	require.True(t, cfg.Permissions.Delete)
+	require.True(t, cfg.Permissions.Update)
 
 	// Reset
 	require.NoError(t, os.Setenv("WD_PORT", ""))
 	require.NoError(t, os.Setenv("WD_DEBUG", ""))
-	require.NoError(t, os.Setenv("WD_MODIFY", ""))
+	require.NoError(t, os.Setenv("WD_PERMISSIONS", ""))
 	require.NoError(t, os.Setenv("WD_DIRECTORY", ""))
 }

lib/handler.go

@@ -2,6 +2,8 @@ package lib
 
 import (
 	"net/http"
+	"net/url"
+	"os"
 	"strings"
 
 	"github.com/rs/cors"
@@ -23,7 +25,7 @@ func NewHandler(c *Config) (http.Handler, error) {
 	h := &Handler{
 		user: &handlerUser{
 			User: User{
-				Permissions: c.Permissions,
+				UserPermissions: c.UserPermissions,
 			},
 			Handler: webdav.Handler{
 				Prefix: c.Prefix,
@@ -100,7 +102,15 @@ func (h *Handler) ServeHTTP(w http.ResponseWriter, r *http.Request) {
 	}
 
 	// Checks for user permissions relatively to this PATH.
-	allowed := user.Allowed(r)
+	allowed := user.Allowed(r, func(destination string) bool {
+		u, err := url.Parse(destination)
+		if err != nil {
+			return false
+		}
+		path := strings.TrimPrefix(u.Path, user.Prefix)
+		_, err = user.FileSystem.Stat(r.Context(), path)
+		return !os.IsNotExist(err)
+	})
 
 	zap.L().Debug("allowed & method & path", zap.Bool("allowed", allowed), zap.String("method", r.Method), zap.String("path", r.URL.Path))
 

lib/handler_test.go

@@ -133,7 +133,7 @@ func TestServerAuthentication(t *testing.T) {
 
 	srv := makeTestServer(t, fmt.Sprintf(`
 directory: %s
-modify: true
+permissions: CRUD
 
 users:
   - username: basic
@@ -191,39 +191,58 @@ func TestServerRules(t *testing.T) {
 		"a/foo.js":  []byte("foo js"),
 		"a/foo.txt": []byte("foo txt"),
 		"b/foo.txt": []byte("foo b"),
+		"c/a.txt":   []byte("b"),
+		"c/b.txt":   []byte("b"),
+		"c/c.txt":   []byte("b"),
 	})
 
 	srv := makeTestServer(t, fmt.Sprintf(`
 directory: %s
-modify: true
+permissions: CRUD
 
 users:
   - username: basic
     password: basic
     rules:
     - regex: "^.+.js$"
-      modify: false
+      permissions: R
     - path: "/b"
-      modify: false
+      permissions: R
+    - path: "/a/foo.txt"
+      permissions: none
+    - path: "/c"
+      permissions: none
 `, dir))
 
 	client := gowebdav.NewClient(srv.URL, "basic", "basic")
 
 	files, err := client.ReadDir("/")
 	require.NoError(t, err)
-	require.Len(t, files, 3)
+	require.Len(t, files, 4)
 
 	err = client.Write("/foo.txt", []byte("new"), 0666)
 	require.NoError(t, err)
 
-	err = client.Write("/a/foo.txt", []byte("new"), 0666)
+	err = client.Write("/new.txt", []byte("new"), 0666)
 	require.NoError(t, err)
 
+	_, err = client.Read("/a/foo.txt")
+	require.ErrorContains(t, err, "403")
+
 	err = client.Write("/a/foo.js", []byte("new"), 0666)
 	require.ErrorContains(t, err, "403")
 
 	err = client.Write("/b/foo.txt", []byte("new"), 0666)
 	require.ErrorContains(t, err, "403")
+
+	_, err = client.ReadDir("/c")
+	require.ErrorContains(t, err, "403")
+
+	_, err = client.Read("/c/a.txt")
+	require.ErrorContains(t, err, "403")
+
+	err = client.Write("/c/b.txt", []byte("new"), 0666)
+	require.ErrorContains(t, err, "403")
 }
 
 func TestServerPermissions(t *testing.T) {
@@ -237,7 +256,7 @@ func TestServerPermissions(t *testing.T) {
 
 	srv := makeTestServer(t, fmt.Sprintf(`
 directory: %s
-modify: true
+permissions: CR
 
 users:
   - username: a
@@ -246,7 +265,7 @@ users:
   - username: b
     password: b
     directory: %s/b
-    modify: false
+    permissions: R
 `, dir, dir, dir))
 
 	t.Run("User A", func(t *testing.T) {
@@ -265,6 +284,12 @@ users:
 		err = client.Copy("/foo.txt", "/copy.txt", false)
 		require.NoError(t, err)
 
+		err = client.Copy("/foo.txt", "/copy.txt", true)
+		require.ErrorContains(t, err, "403")
+
+		err = client.Rename("/foo.txt", "/copy.txt", true)
+		require.ErrorContains(t, err, "403")
+
 		data, err = client.Read("/copy.txt")
 		require.NoError(t, err)
 		require.EqualValues(t, []byte("foo a"), data)

lib/permissions.go

@@ -9,16 +9,8 @@ import (
 	"strings"
 )
 
-var readMethods = []string{
-	http.MethodGet,
-	http.MethodHead,
-	http.MethodOptions,
-	"PROPFIND",
-}
-
 type Rule struct {
-	Allow  bool
+	Permissions Permissions
-	Modify bool
 	Path        string
 	Regex       *regexp.Regexp
 }
@@ -40,36 +32,27 @@ func (r *Rule) Matches(path string) bool {
 	return strings.HasPrefix(path, r.Path)
 }
 
-type Permissions struct {
+type UserPermissions struct {
 	Directory   string
-	Modify    bool
+	Permissions Permissions
 	Rules       []*Rule
 }
 
 // Allowed checks if the user has permission to access a directory/file
-func (p Permissions) Allowed(r *http.Request) bool {
+func (p UserPermissions) Allowed(r *http.Request, destinationExists func(string) bool) bool {
-	// Determine whether or not it is a read or write request.
-	readRequest := false
-	for _, method := range readMethods {
-		if r.Method == method {
-			readRequest = true
-			break
-		}
-	}
-
 	// Go through rules beginning from the last one.
 	for i := len(p.Rules) - 1; i >= 0; i-- {
 		rule := p.Rules[i]
 
 		if rule.Matches(r.URL.Path) {
-			return rule.Allow && (readRequest || rule.Modify)
+			return rule.Permissions.Allowed(r, destinationExists)
 		}
 	}
 
-	return readRequest || p.Modify
+	return p.Permissions.Allowed(r, destinationExists)
 }
 
-func (p *Permissions) Validate() error {
+func (p *UserPermissions) Validate() error {
 	var err error
 
 	p.Directory, err = filepath.Abs(p.Directory)
@@ -85,3 +68,64 @@ func (p *Permissions) Validate() error {
 
 	return nil
 }
+
+type Permissions struct {
+	Create bool
+	Read   bool
+	Update bool
+	Delete bool
+}
+
+func (p *Permissions) UnmarshalText(data []byte) error {
+	text := strings.ToLower(string(data))
+	if text == "none" {
+		return nil
+	}
+
+	for _, c := range text {
+		switch c {
+		case 'c':
+			p.Create = true
+		case 'r':
+			p.Read = true
+		case 'u':
+			p.Update = true
+		case 'd':
+			p.Delete = true
+		default:
+			return fmt.Errorf("invalid permission: %q", c)
+		}
+	}
+
+	return nil
+}
+
+func (p Permissions) Allowed(r *http.Request, destinationExists func(string) bool) bool {
+	switch r.Method {
+	case "GET", "HEAD", "OPTIONS", "POST", "PROPFIND":
+		// Note: POST backend implementation just returns the same thing as GET.
+		return p.Read
+	case "MKCOL":
+		return p.Create
+	case "PROPPATCH":
+		return p.Update
+	case "PUT":
+		if destinationExists(r.URL.Path) {
+			return p.Update
+		} else {
+			return p.Create
+		}
+	case "COPY", "MOVE":
+		if destinationExists(r.Header.Get("Destination")) {
+			return p.Update
+		} else {
+			return p.Create
+		}
+	case "DELETE":
+		return p.Delete
+	case "LOCK", "UNLOCK":
+		return p.Create || p.Read || p.Update || p.Delete
+	default:
+		return false
+	}
+}

lib/user.go

@@ -10,7 +10,7 @@ import (
 )
 
 type User struct {
-	Permissions `mapstructure:",squash"`
+	UserPermissions `mapstructure:",squash"`
 	Username        string
 	Password        string
 }
@@ -44,7 +44,7 @@ func (u *User) Validate() error {
 		}
 	}
 
-	if err := u.Permissions.Validate(); err != nil {
+	if err := u.UserPermissions.Validate(); err != nil {
 		return fmt.Errorf("invalid user %q: %w", u.Username, err)
 	}