security: restrict permissions of imported WireGuard profiles to 0600

WireGuard profile files contain sensitive private keys. Previously, these files were written with 0644 permissions, making them world-readable. This commit changes the file mode to 0600 to ensure only the owner can read and write the profiles.

- Updated `handleProfileImport` to use 0600 permissions.
- Added tests to verify that imported profiles have the correct permissions.

2 files changed, 17 insertions, 2 deletions

diff --git a/internal/cli/cli.go b/internal/cli/cli.go
index a4b9a9a..d100d4f 100644
--- a/internal/cli/cli.go
+++ b/internal/cli/cli.go
@@ -324,7 +324,7 @@ func (a *App) handleProfileImport(srcPath string, name string) error {
 		return fmt.Errorf("failed to read source file: %w", err)
 	}
 
-	if err := os.WriteFile(destPath, data, 0644); err != nil {
+	if err := os.WriteFile(destPath, data, 0600); err != nil {
 		return fmt.Errorf("failed to write profile to %s: %w", destPath, err)
 	}
 
diff --git a/internal/cli/profile_test.go b/internal/cli/profile_test.go
index e08ffc5..d373e95 100644
--- a/internal/cli/profile_test.go
+++ b/internal/cli/profile_test.go
@@ -50,11 +50,19 @@ func TestProfileImport(t *testing.T) {
 		t.Errorf("expected no error, got %v", err)
 	}
 
-	// Verify the file was actually copied to derived name
+	// Verify the file was actually copied to derived name and has correct permissions
 	destFile := filepath.Join(profilesDir, "source.conf")
 	if _, err := os.Stat(destFile); os.IsNotExist(err) {
 		t.Errorf("expected profile to be imported to %s", destFile)
 	}
+	var info os.FileInfo
+	info, err = os.Stat(destFile)
+	if err != nil {
+		t.Fatalf("failed to stat imported profile: %v", err)
+	}
+	if info.Mode().Perm() != 0600 {
+		t.Errorf("expected imported profile to have permissions 0600, got %o", info.Mode().Perm())
+	}
 
 	// 2. Test importing with explicit name argument
 	customName := "custom-vpn"
@@ -70,6 +78,13 @@ func TestProfileImport(t *testing.T) {
 	if _, err := os.Stat(destCustomFile); os.IsNotExist(err) {
 		t.Errorf("expected profile to be imported to %s", destCustomFile)
 	}
+	info, err = os.Stat(destCustomFile)
+	if err != nil {
+		t.Fatalf("failed to stat imported profile: %v", err)
+	}
+	if info.Mode().Perm() != 0600 {
+		t.Errorf("expected imported profile to have permissions 0600, got %o", info.Mode().Perm())
+	}
 
 	// 3. Test duplicate import (should fail)
 	appDup := NewApp([]string{"wg-wrap", "profile", "import", srcFile, customName})