| 1 | //go:build unix |
| 2 | |
| 3 | package hostguard |
| 4 | |
| 5 | import ( |
| 6 | "errors" |
| 7 | "fmt" |
| 8 | "io" |
| 9 | "os" |
| 10 | "path/filepath" |
| 11 | "strings" |
| 12 | "sync" |
| 13 | "testing" |
| 14 | |
| 15 | "golang.org/x/sys/unix" |
| 16 | ) |
| 17 | |
| 18 | func recordFixture(t *testing.T) string { |
| 19 | t.Helper() |
| 20 | dir := t.TempDir() |
| 21 | if err := os.Mkdir(filepath.Join(dir, "hostguard"), 0770); err != nil { |
| 22 | t.Fatal(err) |
| 23 | } |
| 24 | return dir |
| 25 | } |
| 26 | |
| 27 | func TestCaptureStrict(t *testing.T) { |
| 28 | dir := recordFixture(t) |
| 29 | host := "shop.example" |
| 30 | if _, err := Capture(dir, host); !errors.Is(err, ErrNoRecord) { |
| 31 | t.Fatal(err) |
| 32 | } |
| 33 | if _, err := Capture(dir, "../outside"); !errors.Is(err, ErrInvalidHost) { |
| 34 | t.Fatal(err) |
| 35 | } |
| 36 | good := `{"v":1,"host":"shop.example","incarnation":"inc","active_stamp":3,"retired_stamps":[1,2]}` |
| 37 | for _, tc := range []struct { |
| 38 | name, body string |
| 39 | valid bool |
| 40 | }{ |
| 41 | {"good", good, true}, |
| 42 | {"unknown", strings.Replace(good, `"v":1`, `"v":1,"future":true`, 1), false}, |
| 43 | {"trailing", good + `{}`, false}, |
| 44 | {"trailing-garbage", good + `!`, false}, |
| 45 | {"version", strings.Replace(good, `"v":1`, `"v":2`, 1), false}, |
| 46 | {"host", strings.Replace(good, "shop.example", "other.example", 1), false}, |
| 47 | {"incarnation", strings.Replace(good, `"inc"`, `""`, 1), false}, |
| 48 | {"active-retired", strings.Replace(good, `[1,2]`, `[1,3]`, 1), false}, |
| 49 | {"zero-retired", strings.Replace(good, `[1,2]`, `[0,2]`, 1), false}, |
| 50 | {"duplicate", strings.Replace(good, `[1,2]`, `[1,1]`, 1), false}, |
| 51 | {"unordered", strings.Replace(good, `[1,2]`, `[2,1]`, 1), false}, |
| 52 | {"null", `null`, false}, |
| 53 | {"truncated", good[:len(good)-1], false}, |
| 54 | {"negative", strings.Replace(good, `"active_stamp":3`, `"active_stamp":-1`, 1), false}, |
| 55 | } { |
| 56 | t.Run(tc.name, func(t *testing.T) { |
| 57 | if err := os.WriteFile(filepath.Join(dir, "hostguard", host+".json"), []byte(tc.body), 0660); err != nil { |
| 58 | t.Fatal(err) |
| 59 | } |
| 60 | got, err := Capture(dir, host) |
| 61 | if tc.valid { |
| 62 | if err != nil || got != (Captured{Incarnation: "inc", Stamp: 3}) { |
| 63 | t.Fatalf("%+v %v", got, err) |
| 64 | } |
| 65 | } else if !errors.Is(err, ErrMalformedRecord) { |
| 66 | t.Fatal(err) |
| 67 | } |
| 68 | }) |
| 69 | } |
| 70 | } |
| 71 | |
| 72 | func TestRecordAtomicRename(t *testing.T) { |
| 73 | dir, host := recordFixture(t), "shop.example" |
| 74 | r := record{V: 1, Host: host, Incarnation: "inc", ActiveStamp: 1, RetiredStamps: []uint64{}} |
| 75 | if err := writeRecord(dir, r); err != nil { |
| 76 | t.Fatal(err) |
| 77 | } |
| 78 | want := errors.New("rename failed") |
| 79 | r.ActiveStamp = 2 |
| 80 | d, err := openRecordDir(dir) |
| 81 | if err != nil { |
| 82 | t.Fatal(err) |
| 83 | } |
| 84 | defer d.close() |
| 85 | err = d.writeUsing(r, ".rename-test", func(srcFD int, src string, dstFD int, dst string) error { |
| 86 | if srcFD != d.fd || dstFD != d.fd || src != ".rename-test" || dst != host+".json" { |
| 87 | t.Fatal("rename escaped pinned directory") |
| 88 | } |
| 89 | fd, e := unix.Openat(srcFD, src, unix.O_RDONLY|unix.O_NOFOLLOW|unix.O_CLOEXEC, 0) |
| 90 | if e != nil { |
| 91 | t.Fatal(e) |
| 92 | } |
| 93 | f := os.NewFile(uintptr(fd), src) |
| 94 | b, e := io.ReadAll(f) |
| 95 | f.Close() |
| 96 | if e != nil || !strings.Contains(string(b), `"active_stamp":2`) { |
| 97 | t.Fatalf("temporary file: %s %v", b, e) |
| 98 | } |
| 99 | return want |
| 100 | }) |
| 101 | if !errors.Is(err, want) { |
| 102 | t.Fatal(err) |
| 103 | } |
| 104 | got, err := Capture(dir, host) |
| 105 | if err != nil || got.Stamp != 1 { |
| 106 | t.Fatalf("old record: %+v %v", got, err) |
| 107 | } |
| 108 | files, err := os.ReadDir(filepath.Join(dir, "hostguard")) |
| 109 | if err != nil || len(files) != 1 || files[0].Name() != host+".json" { |
| 110 | t.Fatalf("leftovers: %v %v", files, err) |
| 111 | } |
| 112 | |
| 113 | var wg sync.WaitGroup |
| 114 | errs := make(chan error, 1) |
| 115 | done := make(chan struct{}) |
| 116 | wg.Add(1) |
| 117 | go func() { |
| 118 | defer wg.Done() |
| 119 | for { |
| 120 | select { |
| 121 | case <-done: |
| 122 | return |
| 123 | default: |
| 124 | } |
| 125 | c, e := Capture(dir, host) |
| 126 | if e != nil || c.Incarnation != "inc" || c.Stamp == 0 { |
| 127 | select { |
| 128 | case errs <- fmt.Errorf("torn capture: %+v %v", c, e): |
| 129 | default: |
| 130 | } |
| 131 | return |
| 132 | } |
| 133 | } |
| 134 | }() |
| 135 | for i := uint64(2); i <= 40; i++ { |
| 136 | r.ActiveStamp = i |
| 137 | if err := writeRecord(dir, r); err != nil { |
| 138 | close(done) |
| 139 | wg.Wait() |
| 140 | t.Fatal(err) |
| 141 | } |
| 142 | } |
| 143 | close(done) |
| 144 | wg.Wait() |
| 145 | select { |
| 146 | case err := <-errs: |
| 147 | t.Fatal(err) |
| 148 | default: |
| 149 | } |
| 150 | } |
| 151 | |
| 152 | func TestRecordRejectsOversizedHistoryAndReadError(t *testing.T) { |
| 153 | r := record{V: 1, Host: "shop.example", Incarnation: "inc"} |
| 154 | for i := uint64(1); i <= 33; i++ { |
| 155 | r.RetiredStamps = append(r.RetiredStamps, i) |
| 156 | } |
| 157 | if !errors.Is(r.validate(r.Host), ErrMalformedRecord) { |
| 158 | t.Fatal("accepted 33 stamps") |
| 159 | } |
| 160 | dir := t.TempDir() |
| 161 | if err := os.MkdirAll(filepath.Join(dir, "hostguard", r.Host+".json"), 0700); err != nil { |
| 162 | t.Fatal(err) |
| 163 | } |
| 164 | if _, err := Capture(dir, r.Host); err == nil || errors.Is(err, ErrNoRecord) { |
| 165 | t.Fatalf("directory became absence: %v", err) |
| 166 | } |
| 167 | } |
| 168 | |
| 169 | func unchangedFile(t *testing.T, path string) func() { |
| 170 | t.Helper() |
| 171 | before, err := os.Stat(path) |
| 172 | if err != nil { |
| 173 | t.Fatal(err) |
| 174 | } |
| 175 | body, err := os.ReadFile(path) |
| 176 | if err != nil { |
| 177 | t.Fatal(err) |
| 178 | } |
| 179 | return func() { |
| 180 | t.Helper() |
| 181 | after, err := os.Stat(path) |
| 182 | if err != nil { |
| 183 | t.Fatal(err) |
| 184 | } |
| 185 | got, err := os.ReadFile(path) |
| 186 | if err != nil || string(got) != string(body) || before.Mode() != after.Mode() || !os.SameFile(before, after) { |
| 187 | t.Fatalf("target changed: before=%v after=%v body=%q err=%v", before, after, got, err) |
| 188 | } |
| 189 | } |
| 190 | } |
| 191 | |
| 192 | func TestRecordNotProvisioned(t *testing.T) { |
| 193 | dir := t.TempDir() |
| 194 | r := record{V: 1, Host: "shop.example", Incarnation: "inc", ActiveStamp: 1} |
| 195 | if _, err := Capture(dir, r.Host); !errors.Is(err, ErrNotProvisioned) || errors.Is(err, ErrNoRecord) { |
| 196 | t.Fatal(err) |
| 197 | } |
| 198 | if err := writeRecord(dir, r); !errors.Is(err, ErrNotProvisioned) { |
| 199 | t.Fatal(err) |
| 200 | } |
| 201 | if _, err := os.Lstat(filepath.Join(dir, "hostguard")); !errors.Is(err, os.ErrNotExist) { |
| 202 | t.Fatalf("library created directory: %v", err) |
| 203 | } |
| 204 | } |
| 205 | |
| 206 | func TestRecordSymlinksRefused(t *testing.T) { |
| 207 | for _, kind := range []string{"directory", "record", "temp"} { |
| 208 | t.Run(kind, func(t *testing.T) { |
| 209 | dir := recordFixture(t) |
| 210 | host := "shop.example" |
| 211 | r := record{V: 1, Host: host, Incarnation: "inc", ActiveStamp: 2} |
| 212 | outside := t.TempDir() |
| 213 | target := filepath.Join(outside, host+".json") |
| 214 | if err := os.WriteFile(target, []byte(`{"v":1,"host":"shop.example","incarnation":"inc","active_stamp":1,"retired_stamps":[]}`), 0600); err != nil { |
| 215 | t.Fatal(err) |
| 216 | } |
| 217 | defer unchangedFile(t, target)() |
| 218 | guardDir := filepath.Join(dir, "hostguard") |
| 219 | link, destination := filepath.Join(guardDir, host+".json"), target |
| 220 | if kind == "directory" { |
| 221 | if err := os.Remove(guardDir); err != nil { |
| 222 | t.Fatal(err) |
| 223 | } |
| 224 | link, destination = guardDir, outside |
| 225 | } else if kind == "temp" { |
| 226 | link = filepath.Join(guardDir, ".fixed-temp") |
| 227 | } |
| 228 | if err := os.Symlink(destination, link); err != nil { |
| 229 | t.Fatal(err) |
| 230 | } |
| 231 | if kind == "temp" { |
| 232 | d, err := openRecordDir(dir) |
| 233 | if err != nil { |
| 234 | t.Fatal(err) |
| 235 | } |
| 236 | defer d.close() |
| 237 | if err := d.writeUsing(r, ".fixed-temp", unix.Renameat); err == nil { |
| 238 | t.Fatal("accepted temporary symlink") |
| 239 | } |
| 240 | if _, err := d.read(host); !errors.Is(err, ErrNoRecord) { |
| 241 | t.Fatal("published record despite refused temporary file", err) |
| 242 | } |
| 243 | } else { |
| 244 | if _, err := Capture(dir, host); err == nil || errors.Is(err, ErrNoRecord) { |
| 245 | t.Fatal("capture followed symlink", err) |
| 246 | } |
| 247 | if err := writeRecord(dir, r); err == nil { |
| 248 | t.Fatal("write accepted symlink") |
| 249 | } |
| 250 | } |
| 251 | if got, err := os.Readlink(link); err != nil || got != destination { |
| 252 | t.Fatalf("symlink removed or replaced: %q %v", got, err) |
| 253 | } |
| 254 | }) |
| 255 | } |
| 256 | } |
| 257 | |
amadan