| 1 | //go:build linux |
| 2 | |
| 3 | package host |
| 4 | |
| 5 | import ( |
| 6 | "context" |
| 7 | "errors" |
| 8 | "os" |
| 9 | |
| 10 | "github.com/carlosframework/platform/internal/hostbox" |
| 11 | "github.com/carlosframework/platform/internal/hostguard" |
| 12 | "golang.org/x/sys/unix" |
| 13 | ) |
| 14 | |
| 15 | // The parent is established through a root-validated installation before any |
| 16 | // namespace mutation. Startup can retain an obstruction using this evidence |
| 17 | // even after the originating host has gone; it grants no artifact deletion. |
| 18 | type servingParkParent struct { |
| 19 | BootID string `json:",omitempty"` |
| 20 | Version int |
| 21 | Parent servingArtifactDirectory |
| 22 | } |
| 23 | |
| 24 | func (f *servingParkFS) namespaceParent() (servingParkParent, error) { |
| 25 | p, err := f.historicalNamespaceParent() |
| 26 | if err != nil { |
| 27 | return p, err |
| 28 | } |
| 29 | b, err := servingParkReadBinding(f.state, "namespace") |
| 30 | if err != nil || b == nil { |
| 31 | return p, err |
| 32 | } |
| 33 | if p.BootID != b.BeforeBoot || p.Parent != b.BeforeParent { |
| 34 | return p, hostbox.ErrChanged |
| 35 | } |
| 36 | p.BootID, p.Parent = b.BootID, b.Parent |
| 37 | return p, nil |
| 38 | } |
| 39 | |
| 40 | func (f *servingParkFS) historicalNamespaceParent() (servingParkParent, error) { |
| 41 | var p servingParkParent |
| 42 | b, err := f.state.Read("namespace-parent.json") |
| 43 | if err != nil { |
| 44 | return p, err |
| 45 | } |
| 46 | if servingParkDecode(b, &p) != nil || p.Version != 1 || p.Parent.Device == 0 || p.Parent.Inode == 0 || p.Parent.Mount == 0 { |
| 47 | return p, hostbox.ErrChanged |
| 48 | } |
| 49 | return p, nil |
| 50 | } |
| 51 | |
| 52 | // The caller holds namespace and host locks and has checked the claim, root |
| 53 | // installation, inventory and stop evidence. Directory is never a wire path. |
| 54 | func (f *servingParkFS) recordNamespaceParent(ctx context.Context, current servingArtifactIdentity, directory servingArtifactDirectory) error { |
| 55 | if err := ctx.Err(); err != nil { |
| 56 | return err |
| 57 | } |
| 58 | boot, err := f.currentBoot() |
| 59 | if err != nil { |
| 60 | return err |
| 61 | } |
| 62 | source, expected, err := f.source(servingParkAuthorization{Successor: current, Directory: directory}) |
| 63 | if err != nil { |
| 64 | return err |
| 65 | } |
| 66 | defer source.Close() |
| 67 | parent, actual, err := f.parent() |
| 68 | if err != nil { |
| 69 | return err |
| 70 | } |
| 71 | defer parent.Close() |
| 72 | var st unix.Stat_t |
| 73 | if err = unix.Fstat(int(parent.Fd()), &st); err != nil { |
| 74 | return err |
| 75 | } |
| 76 | if actual != expected || st.Mode&0022 != 0 { |
| 77 | return hostbox.ErrChanged |
| 78 | } |
| 79 | p, err := f.namespaceParent() |
| 80 | if err == nil { |
| 81 | if p.Parent != expected || f.checkBoot(p.BootID) != nil { |
| 82 | return hostbox.ErrChanged |
| 83 | } |
| 84 | return nil |
| 85 | } |
| 86 | if !errors.Is(err, os.ErrNotExist) { |
| 87 | return err |
| 88 | } |
| 89 | // Existing private records constrain a first parent capture too. A new |
| 90 | // authenticated host cannot bless a replacement of an older mount parent. |
| 91 | for _, name := range []string{"namespace.json", "namespace-quarantine.json"} { |
| 92 | body, err := f.state.Read(name) |
| 93 | if errors.Is(err, os.ErrNotExist) { |
| 94 | continue |
| 95 | } |
| 96 | if err != nil { |
| 97 | return err |
| 98 | } |
| 99 | if name == "namespace.json" { |
| 100 | var n servingParkNamespace |
| 101 | if servingParkDecode(body, &n) != nil || n.Version != 1 || n.Parent != expected || n.Root.Inode == 0 || n.Root.Device != expected.Device || n.Root.Mount != expected.Mount || f.checkBoot(n.BootID) != nil { |
| 102 | return hostbox.ErrChanged |
| 103 | } |
| 104 | } else { |
| 105 | var q servingParkQuarantine |
| 106 | if servingParkDecode(body, &q) != nil || q.validate() != nil || q.Parent != expected || f.checkBoot(q.BootID) != nil { |
| 107 | return hostbox.ErrChanged |
| 108 | } |
| 109 | } |
| 110 | } |
| 111 | if err = ctx.Err(); err != nil { |
| 112 | return err |
| 113 | } |
| 114 | return (&servingParkLedger{state: f.state}).write("namespace-parent.json", servingParkParent{Version: 1, Parent: expected, BootID: boot}) |
| 115 | } |
| 116 | |
| 117 | // Called under the namespace lock. Absence of parent evidence never permits |
| 118 | // recovery from a pathname alone. A normal empty installation needs no work. |
| 119 | func (f *servingParkFS) recoverRecordedNamespace(ctx context.Context) error { |
| 120 | if err := ctx.Err(); err != nil { |
| 121 | return err |
| 122 | } |
| 123 | p, err := f.namespaceParent() |
| 124 | if errors.Is(err, os.ErrNotExist) { |
| 125 | return nil |
| 126 | } |
| 127 | if err != nil { |
| 128 | return err |
| 129 | } |
| 130 | if err := f.checkBoot(p.BootID); err != nil { |
| 131 | return err |
| 132 | } |
| 133 | parent, id, err := f.parent() |
| 134 | if err != nil { |
| 135 | return err |
| 136 | } |
| 137 | defer parent.Close() |
| 138 | var st unix.Stat_t |
| 139 | if err = unix.Fstat(int(parent.Fd()), &st); err != nil { |
| 140 | return err |
| 141 | } |
| 142 | if id != p.Parent || st.Mode&0022 != 0 { |
| 143 | return hostbox.ErrChanged |
| 144 | } |
| 145 | // An unfinished quarantine must replay before ordinary namespace opening. |
| 146 | if _, err = f.state.Read("namespace-quarantine.json"); err == nil { |
| 147 | _, err = f.recoverNamespace(ctx, p.Parent) |
| 148 | return err |
| 149 | } else if !errors.Is(err, os.ErrNotExist) { |
| 150 | return err |
| 151 | } |
| 152 | n, err := f.readNamespace() |
| 153 | if err == nil { |
| 154 | if n.Version != 1 || n.Parent != p.Parent || n.Root.Inode == 0 || n.Root.Device != id.Device || n.Root.Mount != id.Mount || f.checkBoot(n.BootID) != nil { |
| 155 | return hostbox.ErrChanged |
| 156 | } |
| 157 | root, rid, err := f.privateDir(parent, ".serving-parked") |
| 158 | if err == nil { |
| 159 | root.Close() |
| 160 | if rid == n.Root { |
| 161 | return nil |
| 162 | } |
| 163 | } |
| 164 | } else if errors.Is(err, os.ErrNotExist) { |
| 165 | root, err := servingParkOpenDir(parent, ".serving-parked") |
| 166 | if errors.Is(err, os.ErrNotExist) { |
| 167 | return nil |
| 168 | } |
| 169 | if err != nil { |
| 170 | return err |
| 171 | } |
| 172 | root.Close() |
| 173 | } else { |
| 174 | return err |
| 175 | } |
| 176 | _, err = f.recoverNamespace(ctx, p.Parent) |
| 177 | return err |
| 178 | } |
| 179 | |
| 180 | func (p *servingParkRoot) prepareServingNamespace(ctx context.Context, a servingParkAuthorization, receipts []hostguard.FenceReceipt, legacy *servingLegacyEvidence) error { |
| 181 | fs, ok := p.ledger.fs.(*servingParkFS) |
| 182 | if !ok { |
| 183 | return hostbox.ErrUnsupported |
| 184 | } |
| 185 | if _, err := p.ledger.read(a.ID); errors.Is(err, os.ErrNotExist) { |
| 186 | if err := fs.room(); err != nil { |
| 187 | return err |
| 188 | } |
| 189 | if _, err := p.ledger.capture(ctx, a, receipts, legacy); err != nil { |
| 190 | return err |
| 191 | } |
| 192 | } else if err != nil { |
| 193 | return err |
| 194 | } |
| 195 | if err := fs.recordNamespaceParent(ctx, a.Successor, a.Directory); err != nil { |
| 196 | return err |
| 197 | } |
| 198 | return fs.recoverRecordedNamespace(ctx) |
| 199 | } |
| 200 | |
amadan