| 1 | //go:build linux |
| 2 | |
| 3 | package cgroup |
| 4 | |
| 5 | import ( |
| 6 | "context" |
| 7 | "errors" |
| 8 | "os" |
| 9 | "os/exec" |
| 10 | "path/filepath" |
| 11 | "testing" |
| 12 | "time" |
| 13 | |
| 14 | "golang.org/x/sys/unix" |
| 15 | ) |
| 16 | |
| 17 | func makeRoleFixture(t *testing.T, p *Prepared, role, events string) { |
| 18 | t.Helper() |
| 19 | d := filepath.Join(p.dir.Name(), "role-"+role) |
| 20 | if err := os.Mkdir(d, 0700); err != nil { |
| 21 | t.Fatal(err) |
| 22 | } |
| 23 | for n, v := range map[string]string{"cgroup.events": events, "cgroup.kill": ""} { |
| 24 | if err := os.WriteFile(filepath.Join(d, n), []byte(v), 0600); err != nil { |
| 25 | t.Fatal(err) |
| 26 | } |
| 27 | } |
| 28 | } |
| 29 | |
| 30 | func TestPrepareRoleChildEmptyAndIdentity(t *testing.T) { |
| 31 | p := strictFixture(t) |
| 32 | makeRoleFixture(t, p, "seed", "populated 0\n") |
| 33 | child, err := p.PrepareRoleChild("seed") |
| 34 | if err != nil { |
| 35 | t.Fatal(err) |
| 36 | } |
| 37 | flags, err := unix.FcntlInt(child.entryParent.Fd(), unix.F_GETFD, 0) |
| 38 | if err != nil || flags&unix.FD_CLOEXEC == 0 { |
| 39 | t.Fatalf("parent descriptor may escape exec: flags=%d err=%v", flags, err) |
| 40 | } |
| 41 | id, err := child.Identity() |
| 42 | if err != nil || id.Device == 0 || id.Inode == 0 { |
| 43 | t.Fatalf("identity=%+v %v", id, err) |
| 44 | } |
| 45 | if err := child.Close(); err != nil { |
| 46 | t.Fatal(err) |
| 47 | } |
| 48 | } |
| 49 | |
| 50 | func TestRoleChildCannotOutliveParentCleanup(t *testing.T) { |
| 51 | for _, action := range []string{"kill", "close", "failed-kill", "failed-close"} { |
| 52 | t.Run(action, func(t *testing.T) { |
| 53 | p := strictFixture(t) |
| 54 | makeRoleFixture(t, p, "seed", "populated 0\n") |
| 55 | child, err := p.PrepareRoleChild("seed") |
| 56 | if err != nil { |
| 57 | t.Fatal(err) |
| 58 | } |
| 59 | defer child.Close() |
| 60 | starts := 0 |
| 61 | child.start = func(*exec.Cmd) error { starts++; return nil } |
| 62 | if action == "failed-close" { |
| 63 | if err := strictWrite(p.events, "populated 1\n"); err != nil { |
| 64 | t.Fatal(err) |
| 65 | } |
| 66 | if err := p.Close(); !errors.Is(err, ErrStrictRefused) { |
| 67 | t.Fatalf("failed close=%v", err) |
| 68 | } |
| 69 | // Even once the parent's population drops, cleanup remains latched. |
| 70 | if err := strictWrite(p.events, "populated 0\n"); err != nil { |
| 71 | t.Fatal(err) |
| 72 | } |
| 73 | } else if action == "close" { |
| 74 | if err := p.Close(); err != nil { |
| 75 | t.Fatal(err) |
| 76 | } |
| 77 | } else { |
| 78 | if action == "failed-kill" { |
| 79 | p.kill.Close() |
| 80 | } |
| 81 | ctx, cancel := context.WithTimeout(context.Background(), time.Second) |
| 82 | defer cancel() |
| 83 | err := p.KillAndEmpty(ctx) |
| 84 | if (err != nil) != (action == "failed-kill") { |
| 85 | t.Fatalf("cleanup: %v", err) |
| 86 | } |
| 87 | } |
| 88 | if err := child.Start(exec.Command("unused")); !errors.Is(err, ErrStrictState) || starts != 0 { |
| 89 | t.Fatalf("child reopened drained parent: %v, starts=%d", err, starts) |
| 90 | } |
| 91 | if _, err := p.PrepareRoleChild("another"); !errors.Is(err, ErrStrictState) { |
| 92 | t.Fatalf("new role after cleanup: %v", err) |
| 93 | } |
| 94 | }) |
| 95 | } |
| 96 | } |
| 97 | |
| 98 | func TestRoleChildRechecksParentLimits(t *testing.T) { |
| 99 | p := strictFixture(t) |
| 100 | makeRoleFixture(t, p, "seed", "populated 0\n") |
| 101 | child, err := p.PrepareRoleChild("seed") |
| 102 | if err != nil { |
| 103 | t.Fatal(err) |
| 104 | } |
| 105 | defer child.Close() |
| 106 | if err := strictWrite(p.limits["memory.max"], "0"); err != nil { |
| 107 | t.Fatal(err) |
| 108 | } |
| 109 | if err := child.Start(exec.Command("unused")); !errors.Is(err, ErrStrictRefused) { |
| 110 | t.Fatalf("changed aggregate limit: %v", err) |
| 111 | } |
| 112 | } |
| 113 | |
| 114 | func TestPrepareRoleChildRefusals(t *testing.T) { |
| 115 | t.Run("nonempty", func(t *testing.T) { |
| 116 | p := strictFixture(t) |
| 117 | makeRoleFixture(t, p, "seed", "populated 1\n") |
| 118 | if _, err := p.PrepareRoleChild("seed"); !errors.Is(err, ErrStrictRefused) { |
| 119 | t.Fatalf("err=%v", err) |
| 120 | } |
| 121 | }) |
| 122 | t.Run("symlink", func(t *testing.T) { |
| 123 | p := strictFixture(t) |
| 124 | if err := os.Symlink(t.TempDir(), filepath.Join(p.dir.Name(), "role-seed")); err != nil { |
| 125 | t.Fatal(err) |
| 126 | } |
| 127 | if _, err := p.PrepareRoleChild("seed"); err == nil { |
| 128 | t.Fatal("symlink accepted") |
| 129 | } |
| 130 | }) |
| 131 | t.Run("no-delegation", func(t *testing.T) { |
| 132 | p := strictFixture(t) |
| 133 | if _, err := p.PrepareRoleChild("seed"); !errors.Is(err, ErrStrictUnsupported) { |
| 134 | t.Fatalf("err=%v", err) |
| 135 | } |
| 136 | }) |
| 137 | t.Run("absent-role", func(t *testing.T) { |
| 138 | p := strictFixture(t) |
| 139 | if _, err := p.PrepareRoleChild(""); !errors.Is(err, ErrStrictRefused) { |
| 140 | t.Fatalf("err=%v", err) |
| 141 | } |
| 142 | }) |
| 143 | } |
| 144 | |
| 145 | func TestRoleChildRefusesAfterCleanupAcquisitionCancellation(t *testing.T) { |
| 146 | p := strictFixture(t) |
| 147 | makeRoleFixture(t, p, "seed", "populated 0\n") |
| 148 | child, err := p.PrepareRoleChild("seed") |
| 149 | if err != nil { |
| 150 | t.Fatal(err) |
| 151 | } |
| 152 | defer child.Close() |
| 153 | starts := 0 |
| 154 | child.start = func(*exec.Cmd) error { starts++; return nil } |
| 155 | p.mu.Lock() |
| 156 | ctx, cancel := context.WithTimeout(context.Background(), 20*time.Millisecond) |
| 157 | defer cancel() |
| 158 | done := make(chan error, 1) |
| 159 | go func() { done <- p.KillAndEmpty(ctx) }() |
| 160 | err = <-done |
| 161 | p.mu.Unlock() |
| 162 | if !errors.Is(err, ErrStrictDeadline) { |
| 163 | t.Fatalf("cleanup acquisition: %v", err) |
| 164 | } |
| 165 | if err := child.Start(exec.Command("unused")); !errors.Is(err, ErrStrictState) || starts != 0 { |
| 166 | t.Fatalf("child reopened parent after cancelled cleanup: %v, starts=%d", err, starts) |
| 167 | } |
| 168 | if _, err := p.PrepareRoleChild("another"); !errors.Is(err, ErrStrictState) { |
| 169 | t.Fatalf("new role after cancelled cleanup: %v", err) |
| 170 | } |
| 171 | } |
| 172 | |
| 173 | // TestPrepareRoleChildWithIntentRefusesExistingDirectory verifies that the intent |
| 174 | // path refuses with ErrStrictRefused when the child directory appears between the |
| 175 | // intent callback and mkdir (i.e., the intent callback creates the directory). |
| 176 | func TestPrepareRoleChildWithIntentRefusesExistingDirectory(t *testing.T) { |
| 177 | p := strictFixture(t) |
| 178 | intentCalled := false |
| 179 | intent := func(id ContainmentIdentity) error { |
| 180 | intentCalled = true |
| 181 | // Simulate another actor creating the directory after our intent checks for it |
| 182 | // but before mkdir is called |
| 183 | if err := os.Mkdir(filepath.Join(p.dir.Name(), "role-newchild"), 0700); err != nil { |
| 184 | t.Fatal(err) |
| 185 | } |
| 186 | // Also create the required cgroup files |
| 187 | for n, v := range map[string]string{"cgroup.events": "populated 0\n", "cgroup.kill": ""} { |
| 188 | if err := os.WriteFile(filepath.Join(p.dir.Name(), "role-newchild", n), []byte(v), 0600); err != nil { |
| 189 | t.Fatal(err) |
| 190 | } |
| 191 | } |
| 192 | return nil |
| 193 | } |
| 194 | child, err := p.PrepareRoleChildWithIntent("newchild", intent) |
| 195 | if err != nil && !intentCalled { |
| 196 | t.Fatalf("intent was not called before error: %v", err) |
| 197 | } |
| 198 | if !intentCalled { |
| 199 | t.Fatal("intent callback was not called") |
| 200 | } |
| 201 | if !errors.Is(err, ErrStrictRefused) || child != nil { |
| 202 | t.Fatalf("intent path did not refuse pre-existing directory: err=%v child=%v", err, child) |
| 203 | } |
| 204 | } |
| 205 | |
amadan