| 1 | //go:build linux |
| 2 | |
| 3 | package provisioner |
| 4 | |
| 5 | import ( |
| 6 | "archive/tar" |
| 7 | "crypto/sha256" |
| 8 | "encoding/hex" |
| 9 | "io" |
| 10 | "os" |
| 11 | "path/filepath" |
| 12 | "strings" |
| 13 | |
| 14 | "filippo.io/age" |
| 15 | "golang.org/x/sys/unix" |
| 16 | ) |
| 17 | |
| 18 | const maxRegistryBytes = int64(maxRecords) * (128 << 10) |
| 19 | |
| 20 | type BackupInfo struct { |
| 21 | Digest string `json:"archive_digest"` |
| 22 | Sequence int64 `json:"sequence"` |
| 23 | } |
| 24 | |
| 25 | func existingJournal(statePath, floorPath string, password []byte) (*journal, error) { |
| 26 | if statePath == floorPath || strings.HasPrefix(statePath, floorPath+"/") || strings.HasPrefix(floorPath, statePath+"/") { |
| 27 | return nil, ErrRefused |
| 28 | } |
| 29 | state, e := openPrivateDirectory(statePath) |
| 30 | if e != nil { |
| 31 | return nil, e |
| 32 | } |
| 33 | floorDir, e := openPrivateDirectory(floorPath) |
| 34 | if e != nil { |
| 35 | state.close() |
| 36 | return nil, e |
| 37 | } |
| 38 | fail := func(e error) (*journal, error) { state.close(); floorDir.close(); return nil, e } |
| 39 | wrapped, e := state.read("credential.age", 128<<10) |
| 40 | if e != nil { |
| 41 | return fail(e) |
| 42 | } |
| 43 | id, key, e := unwrapCredential(wrapped, password) |
| 44 | if e != nil { |
| 45 | return fail(e) |
| 46 | } |
| 47 | floor, e := newNativeFloor(floorDir, id) |
| 48 | if e != nil { |
| 49 | return fail(e) |
| 50 | } |
| 51 | j, e := openJournal(state, floor, key, false) |
| 52 | if e != nil { |
| 53 | return fail(e) |
| 54 | } |
| 55 | return j, nil |
| 56 | } |
| 57 | func closeExisting(j *journal) { j.close(); j.floor.dir.close(); j.dir.close() } |
| 58 | func ownedFile(dir *privateDirectory, name string) (*os.File, error) { |
| 59 | if !leaf(name) { |
| 60 | return nil, ErrRefused |
| 61 | } |
| 62 | fd, e := unix.Openat(int(dir.file.Fd()), name, unix.O_WRONLY|unix.O_CREAT|unix.O_EXCL|unix.O_NOFOLLOW|unix.O_CLOEXEC, 0600) |
| 63 | if e != nil { |
| 64 | return nil, ErrRefused |
| 65 | } |
| 66 | return os.NewFile(uintptr(fd), name), nil |
| 67 | } |
| 68 | |
| 69 | // Backup exports only encrypted state. The independent floor is never included. |
| 70 | func Backup(statePath, floorPath, output string, password []byte) (BackupInfo, error) { |
| 71 | if !filepath.IsAbs(output) || filepath.Clean(output) != output || strings.HasPrefix(output, statePath+"/") || strings.HasPrefix(output, floorPath+"/") { |
| 72 | return BackupInfo{}, ErrRefused |
| 73 | } |
| 74 | destination, e := openPrivateDirectory(filepath.Dir(output)) |
| 75 | if e != nil { |
| 76 | return BackupInfo{}, e |
| 77 | } |
| 78 | defer destination.close() |
| 79 | name := filepath.Base(output) |
| 80 | if !leaf(name) || !leaf(name+".tmp") { |
| 81 | return BackupInfo{}, ErrRefused |
| 82 | } |
| 83 | j, e := existingJournal(statePath, floorPath, password) |
| 84 | if e != nil { |
| 85 | return BackupInfo{}, e |
| 86 | } |
| 87 | defer closeExisting(j) |
| 88 | j.mu.Lock() |
| 89 | defer j.mu.Unlock() |
| 90 | point, _, e := j.floor.current() |
| 91 | if e != nil { |
| 92 | return BackupInfo{}, e |
| 93 | } |
| 94 | snapshot, e := ownedFile(j.dir, "backup.snapshot") |
| 95 | if e != nil { |
| 96 | return BackupInfo{}, e |
| 97 | } |
| 98 | snapshot.Close() |
| 99 | defer unix.Unlinkat(int(j.dir.file.Fd()), "backup.snapshot", 0) |
| 100 | snapshotPath := filepath.Join(j.dir.file.Name(), "backup.snapshot") |
| 101 | if _, e = j.db.Exec("VACUUM INTO ?", snapshotPath); e != nil { |
| 102 | return BackupInfo{}, ErrUnavailable |
| 103 | } |
| 104 | dbFile, e := os.Open(snapshotPath) |
| 105 | if e != nil { |
| 106 | return BackupInfo{}, ErrUnavailable |
| 107 | } |
| 108 | defer dbFile.Close() |
| 109 | info, e := dbFile.Stat() |
| 110 | if e != nil || info.Size() > maxRegistryBytes { |
| 111 | return BackupInfo{}, ErrRefused |
| 112 | } |
| 113 | wrapped, e := j.dir.read("credential.age", 128<<10) |
| 114 | if e != nil { |
| 115 | return BackupInfo{}, e |
| 116 | } |
| 117 | genesis, e := j.dir.read("initializing.json", 8192) |
| 118 | if e != nil { |
| 119 | return BackupInfo{}, e |
| 120 | } |
| 121 | outputFile, e := ownedFile(destination, name+".tmp") |
| 122 | if e != nil { |
| 123 | return BackupInfo{}, e |
| 124 | } |
| 125 | defer outputFile.Close() |
| 126 | defer unix.Unlinkat(int(destination.file.Fd()), name+".tmp", 0) |
| 127 | recipient, e := age.NewScryptRecipient(string(password)) |
| 128 | if e != nil { |
| 129 | return BackupInfo{}, ErrRefused |
| 130 | } |
| 131 | digest := sha256.New() |
| 132 | encrypted, e := age.Encrypt(io.MultiWriter(outputFile, digest), recipient) |
| 133 | if e != nil { |
| 134 | return BackupInfo{}, ErrUnavailable |
| 135 | } |
| 136 | archive := tar.NewWriter(encrypted) |
| 137 | for _, entry := range []struct { |
| 138 | name string |
| 139 | size int64 |
| 140 | reader io.Reader |
| 141 | }{{"registry.db", info.Size(), dbFile}, {"credential.age", int64(len(wrapped)), strings.NewReader(string(wrapped))}, {"initializing.json", int64(len(genesis)), strings.NewReader(string(genesis))}} { |
| 142 | if archive.WriteHeader(&tar.Header{Name: entry.name, Mode: 0600, Size: entry.size, Typeflag: tar.TypeReg}) != nil { |
| 143 | return BackupInfo{}, ErrUnavailable |
| 144 | } |
| 145 | if n, e := io.Copy(archive, entry.reader); e != nil || n != entry.size { |
| 146 | return BackupInfo{}, ErrUnavailable |
| 147 | } |
| 148 | } |
| 149 | if archive.Close() != nil || encrypted.Close() != nil || outputFile.Sync() != nil || outputFile.Close() != nil { |
| 150 | return BackupInfo{}, ErrUnavailable |
| 151 | } |
| 152 | if unix.Renameat2(int(destination.file.Fd()), name+".tmp", int(destination.file.Fd()), name, unix.RENAME_NOREPLACE) != nil || destination.file.Sync() != nil { |
| 153 | return BackupInfo{}, ErrRefused |
| 154 | } |
| 155 | return BackupInfo{hex.EncodeToString(digest.Sum(nil)), point.Sequence}, nil |
| 156 | } |
| 157 | |
| 158 | // Restore requires a separate empty destination and the surviving independent |
| 159 | // floor. A failed validation never updates that floor or grants dispatch. |
| 160 | func Restore(statePath, floorPath, input string, password []byte) (RegistryInfo, error) { |
| 161 | if !filepath.IsAbs(input) || filepath.Clean(input) != input || len(password) == 0 || len(password) > 1024 || statePath == floorPath || strings.HasPrefix(statePath, floorPath+"/") || strings.HasPrefix(floorPath, statePath+"/") { |
| 162 | return RegistryInfo{}, ErrRefused |
| 163 | } |
| 164 | state, e := openPrivateDirectory(statePath) |
| 165 | if e != nil { |
| 166 | return RegistryInfo{}, e |
| 167 | } |
| 168 | defer state.close() |
| 169 | names, e := directoryNames(state) |
| 170 | if e != nil || len(names) != 0 { |
| 171 | return RegistryInfo{}, ErrRefused |
| 172 | } |
| 173 | lock, e := state.lock() |
| 174 | if e != nil { |
| 175 | return RegistryInfo{}, e |
| 176 | } |
| 177 | defer lock.Close() |
| 178 | source, e := openPrivateDirectory(filepath.Dir(input)) |
| 179 | if e != nil { |
| 180 | return RegistryInfo{}, e |
| 181 | } |
| 182 | defer source.close() |
| 183 | fd, e := unix.Openat(int(source.file.Fd()), filepath.Base(input), unix.O_RDONLY|unix.O_NOFOLLOW|unix.O_NONBLOCK|unix.O_CLOEXEC, 0) |
| 184 | if e != nil { |
| 185 | return RegistryInfo{}, ErrRefused |
| 186 | } |
| 187 | f := os.NewFile(uintptr(fd), "private-backup") |
| 188 | defer f.Close() |
| 189 | info, e := f.Stat() |
| 190 | if e != nil || !info.Mode().IsRegular() || info.Mode().Perm() != 0600 || info.Size() > maxRegistryBytes+2<<20 { |
| 191 | return RegistryInfo{}, ErrRefused |
| 192 | } |
| 193 | identity, e := age.NewScryptIdentity(string(password)) |
| 194 | if e != nil { |
| 195 | return RegistryInfo{}, ErrRefused |
| 196 | } |
| 197 | identity.SetMaxWorkFactor(18) |
| 198 | decrypted, e := age.Decrypt(f, identity) |
| 199 | if e != nil { |
| 200 | return RegistryInfo{}, ErrRefused |
| 201 | } |
| 202 | archive := tar.NewReader(decrypted) |
| 203 | seen := map[string]bool{} |
| 204 | for { |
| 205 | header, e := archive.Next() |
| 206 | if e == io.EOF { |
| 207 | break |
| 208 | } |
| 209 | if e != nil { |
| 210 | return RegistryInfo{}, ErrRefused |
| 211 | } |
| 212 | limit := int64(0) |
| 213 | switch header.Name { |
| 214 | case "registry.db": |
| 215 | limit = maxRegistryBytes |
| 216 | case "credential.age": |
| 217 | limit = 128 << 10 |
| 218 | case "initializing.json": |
| 219 | limit = 8192 |
| 220 | default: |
| 221 | return RegistryInfo{}, ErrRefused |
| 222 | } |
| 223 | if seen[header.Name] || header.Typeflag != tar.TypeReg || header.Size < 0 || header.Size > limit || header.Mode != 0600 { |
| 224 | return RegistryInfo{}, ErrRefused |
| 225 | } |
| 226 | seen[header.Name] = true |
| 227 | output, e := ownedFile(state, ".restore-"+header.Name) |
| 228 | if e != nil { |
| 229 | return RegistryInfo{}, e |
| 230 | } |
| 231 | n, copyErr := io.Copy(output, archive) |
| 232 | syncErr := output.Sync() |
| 233 | closeErr := output.Close() |
| 234 | if copyErr != nil || syncErr != nil || closeErr != nil || n != header.Size { |
| 235 | return RegistryInfo{}, ErrRefused |
| 236 | } |
| 237 | } |
| 238 | trailing, e := io.ReadAll(io.LimitReader(decrypted, 1)) |
| 239 | if e != nil || len(trailing) != 0 || len(seen) != 3 || state.file.Sync() != nil { |
| 240 | return RegistryInfo{}, ErrRefused |
| 241 | } |
| 242 | for _, name := range []string{"registry.db", "credential.age", "initializing.json"} { |
| 243 | if unix.Renameat2(int(state.file.Fd()), ".restore-"+name, int(state.file.Fd()), name, unix.RENAME_NOREPLACE) != nil { |
| 244 | return RegistryInfo{}, ErrRefused |
| 245 | } |
| 246 | } |
| 247 | if state.file.Sync() != nil { |
| 248 | return RegistryInfo{}, ErrUnavailable |
| 249 | } |
| 250 | lock.Close() |
| 251 | j, e := existingJournal(statePath, floorPath, password) |
| 252 | if e != nil { |
| 253 | return RegistryInfo{}, e |
| 254 | } |
| 255 | defer closeExisting(j) |
| 256 | point, _, e := j.floor.current() |
| 257 | if e != nil { |
| 258 | return RegistryInfo{}, e |
| 259 | } |
| 260 | return RegistryInfo{j.floor.identity.Registry, j.floor.identity.Device, j.floor.identity.Public, point.Sequence}, nil |
| 261 | } |
| 262 | |
amadan