| 1 | //go:build linux |
| 2 | |
| 3 | package instancectl |
| 4 | |
| 5 | import ( |
| 6 | "context" |
| 7 | "errors" |
| 8 | "net" |
| 9 | "os" |
| 10 | "path/filepath" |
| 11 | "testing" |
| 12 | "time" |
| 13 | ) |
| 14 | |
| 15 | func claimFilesystemUnits(t *testing.T) (ClaimUnits, string) { |
| 16 | t.Helper() |
| 17 | root, err := os.MkdirTemp("", "cfs") |
| 18 | if err != nil { |
| 19 | t.Fatal(err) |
| 20 | } |
| 21 | t.Cleanup(func() { os.RemoveAll(root) }) |
| 22 | return ClaimUnits{ExeRoot: filepath.Join(root, "exe"), UnitRoot: filepath.Join(root, "units"), DataRoot: filepath.Join(root, "data"), Systemctl: func(context.Context, ...string) (string, error) { return "", nil }}, "safe.example.com" |
| 23 | } |
| 24 | |
| 25 | func TestClaimFilesystemRootDirRefusesParentSymlinkBeforeCreate(t *testing.T) { |
| 26 | root := t.TempDir() |
| 27 | victim := filepath.Join(root, "victim") |
| 28 | if err := os.Mkdir(victim, 0700); err != nil { |
| 29 | t.Fatal(err) |
| 30 | } |
| 31 | link := filepath.Join(root, "link") |
| 32 | if err := os.Symlink(victim, link); err != nil { |
| 33 | t.Fatal(err) |
| 34 | } |
| 35 | if err := claimRootDir(filepath.Join(link, "created")); err == nil { |
| 36 | t.Fatal("accepted symlink parent") |
| 37 | } |
| 38 | if _, err := os.Lstat(filepath.Join(victim, "created")); !errors.Is(err, os.ErrNotExist) { |
| 39 | t.Fatalf("changed victim before refusal: %v", err) |
| 40 | } |
| 41 | } |
| 42 | |
| 43 | func TestClaimFilesystemClearRefusesSymlinkParents(t *testing.T) { |
| 44 | for _, target := range []string{"source", "dropin"} { |
| 45 | t.Run(target, func(t *testing.T) { |
| 46 | u, host := claimFilesystemUnits(t) |
| 47 | source, dropin, err := u.launchPaths(host) |
| 48 | if err != nil { |
| 49 | t.Fatal(err) |
| 50 | } |
| 51 | victim := t.TempDir() |
| 52 | for _, name := range []string{"launch.json", "permit.json", "exec.sock", "60-claim-launch.conf"} { |
| 53 | if err := os.WriteFile(filepath.Join(victim, name), []byte("victim"), 0600); err != nil { |
| 54 | t.Fatal(err) |
| 55 | } |
| 56 | } |
| 57 | linked, ordinary := source, dropin |
| 58 | if target == "dropin" { |
| 59 | linked, ordinary = dropin, source |
| 60 | } |
| 61 | if err := os.MkdirAll(filepath.Dir(linked), 0700); err != nil { |
| 62 | t.Fatal(err) |
| 63 | } |
| 64 | if err := os.MkdirAll(ordinary, 0700); err != nil { |
| 65 | t.Fatal(err) |
| 66 | } |
| 67 | if err := os.Symlink(victim, linked); err != nil { |
| 68 | t.Fatal(err) |
| 69 | } |
| 70 | if err := u.clearLaunch(context.Background(), host); err == nil { |
| 71 | t.Error("accepted symlink parent") |
| 72 | } |
| 73 | for _, name := range []string{"launch.json", "permit.json", "exec.sock", "60-claim-launch.conf"} { |
| 74 | raw, err := os.ReadFile(filepath.Join(victim, name)) |
| 75 | if err != nil || string(raw) != "victim" { |
| 76 | t.Errorf("victim %s changed: %q, %v", name, raw, err) |
| 77 | } |
| 78 | } |
| 79 | }) |
| 80 | } |
| 81 | } |
| 82 | |
| 83 | func TestClaimFilesystemFreezeReplacesHardlinksWithoutChangingVictim(t *testing.T) { |
| 84 | u, host := claimFilesystemUnits(t) |
| 85 | source, dropin, err := u.launchPaths(host) |
| 86 | if err != nil { |
| 87 | t.Fatal(err) |
| 88 | } |
| 89 | for _, dir := range []string{source, dropin} { |
| 90 | if err := os.MkdirAll(dir, 0700); err != nil { |
| 91 | t.Fatal(err) |
| 92 | } |
| 93 | } |
| 94 | victim := filepath.Join(t.TempDir(), "victim") |
| 95 | if err := os.WriteFile(victim, []byte("victim"), 0600); err != nil { |
| 96 | t.Fatal(err) |
| 97 | } |
| 98 | for _, path := range []string{filepath.Join(source, "launch.json"), filepath.Join(dropin, "60-claim-launch.conf")} { |
| 99 | if err := os.Link(victim, path); err != nil { |
| 100 | t.Fatal(err) |
| 101 | } |
| 102 | } |
| 103 | if err := u.freezeLaunch(context.Background(), host, Launch{Schema: LaunchSchema, Host: host}); err != nil { |
| 104 | t.Fatal(err) |
| 105 | } |
| 106 | raw, err := os.ReadFile(victim) |
| 107 | if err != nil || string(raw) != "victim" { |
| 108 | t.Fatalf("victim changed: %q, %v", raw, err) |
| 109 | } |
| 110 | st, err := os.Stat(victim) |
| 111 | if err != nil { |
| 112 | t.Fatal(err) |
| 113 | } |
| 114 | if st.Mode().Perm() != 0600 { |
| 115 | t.Fatalf("victim mode changed: %o", st.Mode().Perm()) |
| 116 | } |
| 117 | } |
| 118 | |
| 119 | func TestClaimFilesystemExecGateCanonicalSocketRetained(t *testing.T) { |
| 120 | u, host := claimFilesystemUnits(t) |
| 121 | if err := u.freezeLaunch(context.Background(), host, Launch{Schema: LaunchSchema, Host: host}); err != nil { |
| 122 | t.Fatal(err) |
| 123 | } |
| 124 | gate, err := u.prepareExecGate(context.Background(), host, ClaimExecPermit{Reservation: "r", Inputs: "i", BootID: "b", SafeUntil: 1}) |
| 125 | if err != nil { |
| 126 | t.Fatal(err) |
| 127 | } |
| 128 | defer gate.close() |
| 129 | conn, err := net.DialTimeout("unix", gate.path, time.Second) |
| 130 | if err != nil { |
| 131 | t.Fatal(err) |
| 132 | } |
| 133 | conn.Close() |
| 134 | before, err := os.Lstat(gate.path) |
| 135 | if err != nil { |
| 136 | t.Fatal(err) |
| 137 | } |
| 138 | if before.Mode()&os.ModeSocket == 0 || before.Mode().Perm() != 0666 { |
| 139 | t.Fatalf("socket mode = %v", before.Mode()) |
| 140 | } |
| 141 | gate.close() |
| 142 | after, err := os.Lstat(gate.path) |
| 143 | if err != nil || !os.SameFile(before, after) { |
| 144 | t.Fatalf("socket inode removed or replaced: %v", err) |
| 145 | } |
| 146 | } |
| 147 | |
amadan