sshfs_connect/main_test.go

// ABOUTME: Unit tests for sshfsc helpers, primarily the path-traversal guard
// ABOUTME: in verify_mount_dir and the ssh_config field allowlist regexes.

package main

import (
	"os"
	"path/filepath"
	"strings"
	"testing"
)

func TestVerifyMountDir(t *testing.T) {
	home := t.TempDir()
	t.Setenv("HOME", home)
	base := filepath.Join(home, "Servers")
	if err := os.MkdirAll(base, 0700); err != nil {
		t.Fatalf("setup base: %v", err)
	}
	realBase, err := filepath.EvalSymlinks(base)
	if err != nil {
		t.Fatalf("resolve base: %v", err)
	}

	cases := []struct {
		name     string
		hostname string
		wantErr  string // substring; "" means no error
		wantPath string // only checked when wantErr == ""
	}{
		{"normal alias", "server1", "", filepath.Join(realBase, "server1")},
		{"trailing slash", "server1/", "", filepath.Join(realBase, "server1")},
		{"dot in name", "db.prod", "", filepath.Join(realBase, "db.prod")},
		{"parent traversal", "../etc", "escapes mount base", ""},
		{"deep traversal", "../../tmp/x", "escapes mount base", ""},
		{"empty string", "", "escapes mount base", ""},
		{"single dot", ".", "escapes mount base", ""},
		// nested path lands under base — accepted by guard. The hostname allowlist
		// (rxHostUser) rejects slashes upstream; this test pins guard behaviour.
		{"nested path stays under base", "sub/dir", "", filepath.Join(realBase, "sub/dir")},
		// absolute-looking input does not escape because filepath.Join keeps it
		// under base. Same upstream allowlist applies.
		{"absolute-looking input", "/etc/passwd", "", filepath.Join(realBase, "etc/passwd")},
	}

	for _, tc := range cases {
		t.Run(tc.name, func(t *testing.T) {
			got, err := verify_mount_dir(tc.hostname)
			if tc.wantErr != "" {
				if err == nil {
					t.Fatalf("want error containing %q, got nil (path=%q)", tc.wantErr, got)
				}
				if !strings.Contains(err.Error(), tc.wantErr) {
					t.Fatalf("error %q does not contain %q", err.Error(), tc.wantErr)
				}
				return
			}
			if err != nil {
				t.Fatalf("unexpected error: %v", err)
			}
			if got != tc.wantPath {
				t.Fatalf("path = %q, want %q", got, tc.wantPath)
			}
		})
	}
}

func TestValidateSSHFieldRegexes(t *testing.T) {
	cases := []struct {
		name  string
		value string
		rx    string
		ok    bool
	}{
		{"plain host", "myserver", "host", true},
		{"host with dots", "db.prod.example.com", "host", true},
		{"host with hyphen", "edge-01", "host", true},
		{"host leading dash rejected", "-rogue", "host", false},
		{"host with comma rejected", "a,b", "host", false},
		{"host with space rejected", "a b", "host", false},
		{"host with slash rejected", "a/b", "host", false},
		{"host empty rejected", "", "host", false},

		{"identityfile tilde", "~/.ssh/id_ed25519", "ifile", true},
		{"identityfile absolute", "/home/dom/.ssh/id_rsa", "ifile", true},
		{"identityfile letter start", "id_rsa", "ifile", true},
		{"identityfile digit start", "0key", "ifile", true},
		{"identityfile dash mid accepted", "~/.ssh/id-host", "ifile", true},
		{"identityfile with comma rejected", "~/.ssh/id,allow_other", "ifile", false},
		{"identityfile with space rejected", "~/.ssh/id rsa", "ifile", false},
		{"identityfile leading dash rejected", "-Ffoo", "ifile", false},
		{"identityfile leading dot rejected", ".ssh/id", "ifile", false},
		{"identityfile leading colon rejected", ":weird", "ifile", false},
		{"identityfile empty rejected", "", "ifile", false},

		{"remote-dir absolute", "/var/www", "rdir", true},
		{"remote-dir tilde", "~/work", "rdir", true},
		{"remote-dir relative", "projects/foo", "rdir", true},
		{"remote-dir leading dash rejected", "-rf", "rdir", false},
		{"remote-dir leading dot rejected", "./x", "rdir", false},
		{"remote-dir space rejected", "/var /www", "rdir", false},
		{"remote-dir comma rejected", "/a,b", "rdir", false},
		{"remote-dir empty rejected", "", "rdir", false},
	}
	for _, tc := range cases {
		t.Run(tc.name, func(t *testing.T) {
			var rx = rxHostUser
			switch tc.rx {
			case "ifile":
				rx = rxIdentityFile
			case "rdir":
				rx = rxRemoteDir
			}
			err := validate_ssh_field("X", tc.value, rx)
			if tc.ok && err != nil {
				t.Fatalf("want accept, got error: %v", err)
			}
			if !tc.ok && err == nil {
				t.Fatalf("want reject, got accept")
			}
		})
	}
}

func TestVerifyMountDirRejectsSymlink(t *testing.T) {
	home := t.TempDir()
	t.Setenv("HOME", home)
	base := filepath.Join(home, "Servers")
	if err := os.MkdirAll(base, 0700); err != nil {
		t.Fatalf("setup base: %v", err)
	}
	target := t.TempDir()
	if err := os.Symlink(target, filepath.Join(base, "evil")); err != nil {
		t.Fatalf("create symlink: %v", err)
	}
	_, err := verify_mount_dir("evil")
	if err == nil || !strings.Contains(err.Error(), "is a symlink") {
		t.Fatalf("want symlink rejection, got %v", err)
	}
}