| 1 | package hostguard |
| 2 | |
| 3 | import ( |
| 4 | "bytes" |
| 5 | "encoding/json" |
| 6 | "errors" |
| 7 | "fmt" |
| 8 | "io" |
| 9 | |
| 10 | "github.com/carlosframework/platform/internal/controlname" |
| 11 | ) |
| 12 | |
| 13 | var ( |
| 14 | ErrUnsupported = errors.New("hostguard: unsupported platform") |
| 15 | ErrNotProvisioned = errors.New("hostguard: directory not provisioned") |
| 16 | ErrUnsafeFile = errors.New("hostguard: expected regular file") |
| 17 | ErrInvalidHost = errors.New("hostguard: invalid host") |
| 18 | ErrHostTooLong = errors.New("hostguard: host too long for record or lock filename") |
| 19 | ErrNoRecord = errors.New("hostguard: no local record") |
| 20 | ErrMalformedRecord = errors.New("hostguard: malformed local record") |
| 21 | ) |
| 22 | |
| 23 | type Captured struct { |
| 24 | Incarnation string |
| 25 | Stamp uint64 |
| 26 | } |
| 27 | |
| 28 | type record struct { |
| 29 | migrationDenies []MigrationDeny |
| 30 | quarantined bool |
| 31 | // settled marks a quarantine whose only cause is root's terminal |
| 32 | // resolution of a pending intent: an obsolete binding (roster binding |
| 33 | // N3) or a claim proven to have superseded it. It never lifts the |
| 34 | // quarantine's execution refusal; the refusal-only migration census |
| 35 | // alone may inspect such an installation. |
| 36 | settled bool |
| 37 | root bool |
| 38 | installation RootInstallation |
| 39 | rootRetired []Captured |
| 40 | rebindCommit []byte |
| 41 | pendingInventory []byte |
| 42 | pendingInstallation *RootInstallation |
| 43 | barrier *FenceTarget |
| 44 | V int `json:"v"` |
| 45 | Host string `json:"host"` |
| 46 | Incarnation string `json:"incarnation"` |
| 47 | ActiveStamp uint64 `json:"active_stamp"` |
| 48 | RetiredStamps []uint64 `json:"retired_stamps"` |
| 49 | ActiveFence *FenceTarget `json:"active_fence,omitempty"` |
| 50 | FenceJournal []FenceReceipt `json:"fence_journal,omitempty"` |
| 51 | } |
| 52 | |
| 53 | func (r record) validate(host string) error { |
| 54 | if r.V != 1 || r.Host != host || !controlname.ValidHostShape(host) || r.Incarnation == "" || (!r.root && len(r.RetiredStamps) > 32) { |
| 55 | return ErrMalformedRecord |
| 56 | } |
| 57 | var previous uint64 |
| 58 | for _, s := range r.RetiredStamps { |
| 59 | if s == 0 || s <= previous || (r.ActiveStamp != 0 && s >= r.ActiveStamp) { |
| 60 | return ErrMalformedRecord |
| 61 | } |
| 62 | previous = s |
| 63 | } |
| 64 | if r.ActiveFence != nil { |
| 65 | if err := r.ActiveFence.validate(host); err != nil { |
| 66 | return err |
| 67 | } |
| 68 | } |
| 69 | for i := range r.FenceJournal { |
| 70 | if err := r.FenceJournal[i].validate(host); err != nil { |
| 71 | return err |
| 72 | } |
| 73 | if i > 0 && r.FenceJournal[i-1].Target == r.FenceJournal[i].Target { |
| 74 | return ErrMalformedRecord |
| 75 | } |
| 76 | } |
| 77 | return nil |
| 78 | } |
| 79 | |
| 80 | func validateFileHost(host string) error { |
| 81 | if !controlname.ValidHostShape(host) { |
| 82 | return ErrInvalidHost |
| 83 | } |
| 84 | if len(host)+len(".json") > 255 || len(host)+len(".lock") > 255 { |
| 85 | return ErrHostTooLong |
| 86 | } |
| 87 | return nil |
| 88 | } |
| 89 | |
| 90 | func readRecord(dataDir, host string) (record, error) { |
| 91 | if err := validateFileHost(host); err != nil { |
| 92 | return record{}, err |
| 93 | } |
| 94 | d, err := openRecordDir(dataDir) |
| 95 | if err != nil { |
| 96 | return record{}, err |
| 97 | } |
| 98 | defer d.close() |
| 99 | return d.read(host) |
| 100 | } |
| 101 | |
| 102 | func decodeRecord(b []byte, host string) (record, error) { |
| 103 | d := json.NewDecoder(bytes.NewReader(b)) |
| 104 | d.DisallowUnknownFields() |
| 105 | var r record |
| 106 | if err := d.Decode(&r); err != nil { |
| 107 | return record{}, fmt.Errorf("%w: %v", ErrMalformedRecord, err) |
| 108 | } |
| 109 | if _, err := d.Token(); err != io.EOF { |
| 110 | return record{}, ErrMalformedRecord |
| 111 | } |
| 112 | if err := r.validate(host); err != nil { |
| 113 | return record{}, err |
| 114 | } |
| 115 | return r, nil |
| 116 | } |
| 117 | |
| 118 | func Capture(dataDir, host string) (Captured, error) { |
| 119 | r, err := readRecord(dataDir, host) |
| 120 | if err != nil { |
| 121 | return Captured{}, err |
| 122 | } |
| 123 | return Captured{Incarnation: r.Incarnation, Stamp: r.ActiveStamp}, nil |
| 124 | } |
| 125 | |
| 126 | func writeRecord(dataDir string, r record) error { |
| 127 | if err := validateFileHost(r.Host); err != nil { |
| 128 | return err |
| 129 | } |
| 130 | if err := r.validate(r.Host); err != nil { |
| 131 | return err |
| 132 | } |
| 133 | d, err := openRecordDir(dataDir) |
| 134 | if err != nil { |
| 135 | return err |
| 136 | } |
| 137 | defer d.close() |
| 138 | return d.write(r) |
| 139 | } |
| 140 | |
amadan