Warn about permissions when creating identity (#1384)

* Warn about permissions when creating identity

* Function to determine if directory is writeable

* Check if writable before authorizing

* Remove redeclatarion

* remove windows specific utils

* Nat nits

* Actually test if directory is writeable with file creation

cmd/certificates/setup.go

@@ -55,7 +55,11 @@ func cmdSetup(cmd *cobra.Command, args []string) error {
 		return err
 	}
 
-	if config.Identity.Status() != identity.CertKey {
+	status, err := config.Identity.Status()
+	if err != nil {
+		return err
+	}
+	if status != identity.CertKey {
 		return errors.New("identity is missing")
 	}
 

cmd/identity/identity.go

@@ -79,7 +79,10 @@ func cmdNewID(cmd *cobra.Command, args []string) (err error) {
 		return err
 	}
 
-	s := newIDCfg.Identity.Status()
+	s, err := newIDCfg.Identity.Status()
+	if err != nil {
+		return err
+	}
 	if s == identity.NoCertNoKey || newIDCfg.Identity.Overwrite {
 		_, err := newIDCfg.Identity.Create(ca)
 		return err

cmd/identity/main.go

@@ -20,6 +20,7 @@ import (
 	"storj.io/storj/pkg/peertls"
 	"storj.io/storj/pkg/pkcrypto"
 	"storj.io/storj/pkg/process"
+	"storj.io/storj/pkg/utils"
 )
 
 const (
@@ -71,6 +72,11 @@ func init() {
 }
 
 func main() {
+	if writable, err := utils.IsWritable(identityDir); !writable || err != nil {
+		fmt.Printf("%s is not a writeable directory: %s\n", identityDir, err)
+		return
+	}
+
 	process.Exec(rootCmd)
 }
 
@@ -95,8 +101,12 @@ func cmdNewService(cmd *cobra.Command, args []string) error {
 		ParentKeyPath:  config.ParentKeyPath,
 	}
 
-	if caConfig.Status() != identity.NoCertNoKey {
-		return errs.New("CA certificate and/or key already exits, NOT overwriting!")
+	status, err := caConfig.Status()
+	if err != nil {
+		return err
+	}
+	if status != identity.NoCertNoKey {
+		return errs.New("CA certificate and/or key already exists, NOT overwriting!")
 	}
 
 	identConfig := identity.SetupConfig{
@@ -104,8 +114,12 @@ func cmdNewService(cmd *cobra.Command, args []string) error {
 		KeyPath:  identKeyPath,
 	}
 
-	if identConfig.Status() != identity.NoCertNoKey {
-		return errs.New("Identity certificate and/or key already exits, NOT overwriting!")
+	status, err = identConfig.Status()
+	if err != nil {
+		return err
+	}
+	if status != identity.NoCertNoKey {
+		return errs.New("Identity certificate and/or key already exists, NOT overwriting!")
 	}
 
 	ca, caerr := caConfig.Create(process.Ctx(cmd), os.Stdout)
@@ -128,6 +142,7 @@ func cmdAuthorize(cmd *cobra.Command, args []string) error {
 	ctx := process.Ctx(cmd)
 
 	serviceDir := serviceDirectory(args[0])
+
 	authToken := args[1]
 
 	caCertPath := filepath.Join(serviceDir, "ca.cert")

pkg/identity/certificate_authority.go

@@ -176,7 +176,7 @@ func NewCA(ctx context.Context, opts NewCAOptions) (_ *FullCertificateAuthority,
 }
 
 // Status returns the status of the CA cert/key files for the config
-func (caS CASetupConfig) Status() TLSFilesStatus {
+func (caS CASetupConfig) Status() (TLSFilesStatus, error) {
 	return statTLSFiles(caS.CertPath, caS.KeyPath)
 }
 

pkg/identity/identity.go

@@ -263,7 +263,7 @@ func ToChains(chains ...[]*x509.Certificate) [][]*x509.Certificate {
 }
 
 // Status returns the status of the identity cert/key files for the config
-func (is SetupConfig) Status() TLSFilesStatus {
+func (is SetupConfig) Status() (TLSFilesStatus, error) {
 	return statTLSFiles(is.CertPath, is.KeyPath)
 }
 

pkg/identity/utils.go

@@ -58,22 +58,37 @@ func writeFile(path string, dirmode, filemode os.FileMode, data []byte) error {
 	return nil
 }
 
-func statTLSFiles(certPath, keyPath string) TLSFilesStatus {
-	_, err := os.Stat(certPath)
-	hasCert := !os.IsNotExist(err)
+func statTLSFiles(certPath, keyPath string) (status TLSFilesStatus, err error) {
+	hasKey := true
+	hasCert := true
 
-	_, err = os.Stat(keyPath)
-	hasKey := !os.IsNotExist(err)
-
-	if hasCert && hasKey {
-		return CertKey
-	} else if hasCert {
-		return CertNoKey
-	} else if hasKey {
-		return NoCertKey
+	_, err = os.Stat(certPath)
+	if err != nil {
+		if os.IsNotExist(err) {
+			hasCert = false
+		} else {
+			return NoCertNoKey, err
+		}
 	}
 
-	return NoCertNoKey
+	_, err = os.Stat(keyPath)
+	if err != nil {
+		if os.IsNotExist(err) {
+			hasKey = false
+		} else {
+			return NoCertNoKey, err
+		}
+	}
+
+	if hasCert && hasKey {
+		return CertKey, nil
+	} else if hasCert {
+		return CertNoKey, nil
+	} else if hasKey {
+		return NoCertKey, nil
+	}
+
+	return NoCertNoKey, nil
 }
 
 func (t TLSFilesStatus) String() string {

pkg/utils/utils.go

@@ -4,6 +4,8 @@
 package utils
 
 import (
+	"os"
+	"path"
 	"time"
 
 	"github.com/zeebo/errs"
@@ -84,3 +86,35 @@ func discardNil(ch chan error) chan error {
 	}()
 	return r
 }
+
+// IsWritable determines if a directory is writeable
+func IsWritable(filepath string) (bool, error) {
+	info, err := os.Stat(filepath)
+	if err != nil {
+		return false, err
+	}
+
+	if !info.IsDir() {
+		return false, errs.New("Path %s is not a directory", filepath)
+	}
+
+	// Check if the user bit is enabled in file permission
+	if info.Mode().Perm()&0200 == 0 {
+		return false, errs.New("Write permission bit is not set on this file for user")
+	}
+
+	// Test if user can create file
+	// There is no OS cross-compatible method for
+	// determining if a user has write permissions on a folder.
+	// We can test by attempting to create a file in the folder.
+	testFile := path.Join(filepath, ".perm")
+	file, err := os.Create(testFile) // For read access.
+	if err != nil {
+		return false, errs.New("Write permission bit is not set on this file for user")
+	}
+
+	_ = file.Close()
+	_ = os.Remove(testFile)
+
+	return true, nil
+}