diff options
Diffstat (limited to 'pkg/sentry/fsimpl/testutil')
| -rw-r--r-- | pkg/sentry/fsimpl/testutil/BUILD | 36 | ||||
| -rw-r--r-- | pkg/sentry/fsimpl/testutil/kernel.go | 149 | ||||
| -rw-r--r-- | pkg/sentry/fsimpl/testutil/testutil.go | 281 |
3 files changed, 466 insertions, 0 deletions
diff --git a/pkg/sentry/fsimpl/testutil/BUILD b/pkg/sentry/fsimpl/testutil/BUILD new file mode 100644 index 000000000..4e70d84a7 --- /dev/null +++ b/pkg/sentry/fsimpl/testutil/BUILD @@ -0,0 +1,36 @@ +load("//tools/go_stateify:defs.bzl", "go_library") + +package(licenses = ["notice"]) + +go_library( + name = "testutil", + testonly = 1, + srcs = [ + "kernel.go", + "testutil.go", + ], + importpath = "gvisor.dev/gvisor/pkg/sentry/fsimpl/testutil", + visibility = ["//pkg/sentry:internal"], + deps = [ + "//pkg/abi/linux", + "//pkg/cpuid", + "//pkg/fspath", + "//pkg/memutil", + "//pkg/sentry/context", + "//pkg/sentry/fs", + "//pkg/sentry/kernel", + "//pkg/sentry/kernel/auth", + "//pkg/sentry/kernel/sched", + "//pkg/sentry/limits", + "//pkg/sentry/loader", + "//pkg/sentry/pgalloc", + "//pkg/sentry/platform", + "//pkg/sentry/platform/kvm", + "//pkg/sentry/platform/ptrace", + "//pkg/sentry/time", + "//pkg/sentry/usermem", + "//pkg/sentry/vfs", + "//pkg/sync", + "@com_github_google_go-cmp//cmp:go_default_library", + ], +) diff --git a/pkg/sentry/fsimpl/testutil/kernel.go b/pkg/sentry/fsimpl/testutil/kernel.go new file mode 100644 index 000000000..295da2d52 --- /dev/null +++ b/pkg/sentry/fsimpl/testutil/kernel.go @@ -0,0 +1,149 @@ +// Copyright 2019 The gVisor Authors. +// +// Licensed under the Apache License, Version 2.0 (the "License"); +// you may not use this file except in compliance with the License. +// You may obtain a copy of the License at +// +// http://www.apache.org/licenses/LICENSE-2.0 +// +// Unless required by applicable law or agreed to in writing, software +// distributed under the License is distributed on an "AS IS" BASIS, +// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. +// See the License for the specific language governing permissions and +// limitations under the License. + +package testutil + +import ( + "flag" + "fmt" + "os" + "runtime" + + "gvisor.dev/gvisor/pkg/abi/linux" + "gvisor.dev/gvisor/pkg/cpuid" + "gvisor.dev/gvisor/pkg/memutil" + "gvisor.dev/gvisor/pkg/sentry/context" + "gvisor.dev/gvisor/pkg/sentry/fs" + "gvisor.dev/gvisor/pkg/sentry/kernel" + "gvisor.dev/gvisor/pkg/sentry/kernel/auth" + "gvisor.dev/gvisor/pkg/sentry/kernel/sched" + "gvisor.dev/gvisor/pkg/sentry/limits" + "gvisor.dev/gvisor/pkg/sentry/loader" + "gvisor.dev/gvisor/pkg/sentry/pgalloc" + "gvisor.dev/gvisor/pkg/sentry/platform" + "gvisor.dev/gvisor/pkg/sentry/time" + + // Platforms are plugable. + _ "gvisor.dev/gvisor/pkg/sentry/platform/kvm" + _ "gvisor.dev/gvisor/pkg/sentry/platform/ptrace" +) + +var ( + platformFlag = flag.String("platform", "ptrace", "specify which platform to use") +) + +// Boot initializes a new bare bones kernel for test. +func Boot() (*kernel.Kernel, error) { + platformCtr, err := platform.Lookup(*platformFlag) + if err != nil { + return nil, fmt.Errorf("platform not found: %v", err) + } + deviceFile, err := platformCtr.OpenDevice() + if err != nil { + return nil, fmt.Errorf("creating platform: %v", err) + } + plat, err := platformCtr.New(deviceFile) + if err != nil { + return nil, fmt.Errorf("creating platform: %v", err) + } + + k := &kernel.Kernel{ + Platform: plat, + } + + mf, err := createMemoryFile() + if err != nil { + return nil, err + } + k.SetMemoryFile(mf) + + // Pass k as the platform since it is savable, unlike the actual platform. + vdso, err := loader.PrepareVDSO(nil, k) + if err != nil { + return nil, fmt.Errorf("creating vdso: %v", err) + } + + // Create timekeeper. + tk, err := kernel.NewTimekeeper(k, vdso.ParamPage.FileRange()) + if err != nil { + return nil, fmt.Errorf("creating timekeeper: %v", err) + } + tk.SetClocks(time.NewCalibratedClocks()) + + creds := auth.NewRootCredentials(auth.NewRootUserNamespace()) + + // Initiate the Kernel object, which is required by the Context passed + // to createVFS in order to mount (among other things) procfs. + if err = k.Init(kernel.InitKernelArgs{ + ApplicationCores: uint(runtime.GOMAXPROCS(-1)), + FeatureSet: cpuid.HostFeatureSet(), + Timekeeper: tk, + RootUserNamespace: creds.UserNamespace, + Vdso: vdso, + RootUTSNamespace: kernel.NewUTSNamespace("hostname", "domain", creds.UserNamespace), + RootIPCNamespace: kernel.NewIPCNamespace(creds.UserNamespace), + RootAbstractSocketNamespace: kernel.NewAbstractSocketNamespace(), + PIDNamespace: kernel.NewRootPIDNamespace(creds.UserNamespace), + }); err != nil { + return nil, fmt.Errorf("initializing kernel: %v", err) + } + + ctx := k.SupervisorContext() + + // Create mount namespace without root as it's the minimum required to create + // the global thread group. + mntns, err := fs.NewMountNamespace(ctx, nil) + if err != nil { + return nil, err + } + ls, err := limits.NewLinuxLimitSet() + if err != nil { + return nil, err + } + tg := k.NewThreadGroup(mntns, k.RootPIDNamespace(), kernel.NewSignalHandlers(), linux.SIGCHLD, ls) + k.TestOnly_SetGlobalInit(tg) + + return k, nil +} + +// CreateTask creates a new bare bones task for tests. +func CreateTask(ctx context.Context, name string, tc *kernel.ThreadGroup) (*kernel.Task, error) { + k := kernel.KernelFromContext(ctx) + config := &kernel.TaskConfig{ + Kernel: k, + ThreadGroup: tc, + TaskContext: &kernel.TaskContext{Name: name}, + Credentials: auth.CredentialsFromContext(ctx), + AllowedCPUMask: sched.NewFullCPUSet(k.ApplicationCores()), + UTSNamespace: kernel.UTSNamespaceFromContext(ctx), + IPCNamespace: kernel.IPCNamespaceFromContext(ctx), + AbstractSocketNamespace: kernel.NewAbstractSocketNamespace(), + } + return k.TaskSet().NewTask(config) +} + +func createMemoryFile() (*pgalloc.MemoryFile, error) { + const memfileName = "test-memory" + memfd, err := memutil.CreateMemFD(memfileName, 0) + if err != nil { + return nil, fmt.Errorf("error creating memfd: %v", err) + } + memfile := os.NewFile(uintptr(memfd), memfileName) + mf, err := pgalloc.NewMemoryFile(memfile, pgalloc.MemoryFileOpts{}) + if err != nil { + memfile.Close() + return nil, fmt.Errorf("error creating pgalloc.MemoryFile: %v", err) + } + return mf, nil +} diff --git a/pkg/sentry/fsimpl/testutil/testutil.go b/pkg/sentry/fsimpl/testutil/testutil.go new file mode 100644 index 000000000..2a723a89f --- /dev/null +++ b/pkg/sentry/fsimpl/testutil/testutil.go @@ -0,0 +1,281 @@ +// Copyright 2019 The gVisor Authors. +// +// Licensed under the Apache License, Version 2.0 (the "License"); +// you may not use this file except in compliance with the License. +// You may obtain a copy of the License at +// +// http://www.apache.org/licenses/LICENSE-2.0 +// +// Unless required by applicable law or agreed to in writing, software +// distributed under the License is distributed on an "AS IS" BASIS, +// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. +// See the License for the specific language governing permissions and +// limitations under the License. + +// Package testutil provides common test utilities for kernfs-based +// filesystems. +package testutil + +import ( + "fmt" + "io" + "strings" + "testing" + + "github.com/google/go-cmp/cmp" + "gvisor.dev/gvisor/pkg/abi/linux" + "gvisor.dev/gvisor/pkg/fspath" + "gvisor.dev/gvisor/pkg/sentry/context" + "gvisor.dev/gvisor/pkg/sentry/kernel/auth" + "gvisor.dev/gvisor/pkg/sentry/usermem" + "gvisor.dev/gvisor/pkg/sentry/vfs" + "gvisor.dev/gvisor/pkg/sync" +) + +// System represents the context for a single test. +// +// Test systems must be explicitly destroyed with System.Destroy. +type System struct { + t *testing.T + Ctx context.Context + Creds *auth.Credentials + VFS *vfs.VirtualFilesystem + Root vfs.VirtualDentry + mns *vfs.MountNamespace +} + +// NewSystem constructs a System. +// +// Precondition: Caller must hold a reference on mns, whose ownership +// is transferred to the new System. +func NewSystem(ctx context.Context, t *testing.T, v *vfs.VirtualFilesystem, mns *vfs.MountNamespace) *System { + s := &System{ + t: t, + Ctx: ctx, + Creds: auth.CredentialsFromContext(ctx), + VFS: v, + mns: mns, + Root: mns.Root(), + } + return s +} + +// WithSubtest creates a temporary test system with a new test harness, +// referencing all other resources from the original system. This is useful when +// a system is reused for multiple subtests, and the T needs to change for each +// case. Note that this is safe when test cases run in parallel, as all +// resources referenced by the system are immutable, or handle interior +// mutations in a thread-safe manner. +// +// The returned system must not outlive the original and should not be destroyed +// via System.Destroy. +func (s *System) WithSubtest(t *testing.T) *System { + return &System{ + t: t, + Ctx: s.Ctx, + Creds: s.Creds, + VFS: s.VFS, + mns: s.mns, + Root: s.Root, + } +} + +// WithTemporaryContext constructs a temporary test system with a new context +// ctx. The temporary system borrows all resources and references from the +// original system. The returned temporary system must not outlive the original +// system, and should not be destroyed via System.Destroy. +func (s *System) WithTemporaryContext(ctx context.Context) *System { + return &System{ + t: s.t, + Ctx: ctx, + Creds: s.Creds, + VFS: s.VFS, + mns: s.mns, + Root: s.Root, + } +} + +// Destroy release resources associated with a test system. +func (s *System) Destroy() { + s.Root.DecRef() + s.mns.DecRef(s.VFS) // Reference on mns passed to NewSystem. +} + +// ReadToEnd reads the contents of fd until EOF to a string. +func (s *System) ReadToEnd(fd *vfs.FileDescription) (string, error) { + buf := make([]byte, usermem.PageSize) + bufIOSeq := usermem.BytesIOSequence(buf) + opts := vfs.ReadOptions{} + + var content strings.Builder + for { + n, err := fd.Read(s.Ctx, bufIOSeq, opts) + if n == 0 || err != nil { + if err == io.EOF { + err = nil + } + return content.String(), err + } + content.Write(buf[:n]) + } +} + +// PathOpAtRoot constructs a PathOperation with the given path from +// the root of the filesystem. +func (s *System) PathOpAtRoot(path string) *vfs.PathOperation { + return &vfs.PathOperation{ + Root: s.Root, + Start: s.Root, + Path: fspath.Parse(path), + } +} + +// GetDentryOrDie attempts to resolve a dentry referred to by the +// provided path operation. If unsuccessful, the test fails. +func (s *System) GetDentryOrDie(pop *vfs.PathOperation) vfs.VirtualDentry { + vd, err := s.VFS.GetDentryAt(s.Ctx, s.Creds, pop, &vfs.GetDentryOptions{}) + if err != nil { + s.t.Fatalf("GetDentryAt(pop:%+v) failed: %v", pop, err) + } + return vd +} + +// DirentType is an alias for values for linux_dirent64.d_type. +type DirentType = uint8 + +// ListDirents lists the Dirents for a directory at pop. +func (s *System) ListDirents(pop *vfs.PathOperation) *DirentCollector { + fd, err := s.VFS.OpenAt(s.Ctx, s.Creds, pop, &vfs.OpenOptions{Flags: linux.O_RDONLY}) + if err != nil { + s.t.Fatalf("OpenAt for PathOperation %+v failed: %v", pop, err) + } + defer fd.DecRef() + + collector := &DirentCollector{} + if err := fd.IterDirents(s.Ctx, collector); err != nil { + s.t.Fatalf("IterDirent failed: %v", err) + } + return collector +} + +// AssertAllDirentTypes verifies that the set of dirents in collector contains +// exactly the specified set of expected entries. AssertAllDirentTypes respects +// collector.skipDots, and implicitly checks for "." and ".." accordingly. +func (s *System) AssertAllDirentTypes(collector *DirentCollector, expected map[string]DirentType) { + // Also implicitly check for "." and "..", if enabled. + if !collector.skipDots { + expected["."] = linux.DT_DIR + expected[".."] = linux.DT_DIR + } + + dentryTypes := make(map[string]DirentType) + collector.mu.Lock() + for _, dirent := range collector.dirents { + dentryTypes[dirent.Name] = dirent.Type + } + collector.mu.Unlock() + if diff := cmp.Diff(expected, dentryTypes); diff != "" { + s.t.Fatalf("IterDirent had unexpected results:\n--- want\n+++ got\n%v", diff) + } +} + +// AssertDirentOffsets verifies that collector contains at least the entries +// specified in expected, with the given NextOff field. Entries specified in +// expected but missing from collector result in failure. Extra entries in +// collector are ignored. AssertDirentOffsets respects collector.skipDots, and +// implicitly checks for "." and ".." accordingly. +func (s *System) AssertDirentOffsets(collector *DirentCollector, expected map[string]int64) { + // Also implicitly check for "." and "..", if enabled. + if !collector.skipDots { + expected["."] = 1 + expected[".."] = 2 + } + + dentryNextOffs := make(map[string]int64) + collector.mu.Lock() + for _, dirent := range collector.dirents { + // Ignore extra entries in dentries that are not in expected. + if _, ok := expected[dirent.Name]; ok { + dentryNextOffs[dirent.Name] = dirent.NextOff + } + } + collector.mu.Unlock() + if diff := cmp.Diff(expected, dentryNextOffs); diff != "" { + s.t.Fatalf("IterDirent had unexpected results:\n--- want\n+++ got\n%v", diff) + } +} + +// DirentCollector provides an implementation for vfs.IterDirentsCallback for +// testing. It simply iterates to the end of a given directory FD and collects +// all dirents emitted by the callback. +type DirentCollector struct { + mu sync.Mutex + order []*vfs.Dirent + dirents map[string]*vfs.Dirent + // When the collector is used in various Assert* functions, should "." and + // ".." be implicitly checked? + skipDots bool +} + +// SkipDotsChecks enables or disables the implicit checks on "." and ".." when +// the collector is used in various Assert* functions. Note that "." and ".." +// are still collected if passed to d.Handle, so the caller should only disable +// the checks when they aren't expected. +func (d *DirentCollector) SkipDotsChecks(value bool) { + d.skipDots = value +} + +// Handle implements vfs.IterDirentsCallback.Handle. +func (d *DirentCollector) Handle(dirent vfs.Dirent) bool { + d.mu.Lock() + if d.dirents == nil { + d.dirents = make(map[string]*vfs.Dirent) + } + d.order = append(d.order, &dirent) + d.dirents[dirent.Name] = &dirent + d.mu.Unlock() + return true +} + +// Count returns the number of dirents currently in the collector. +func (d *DirentCollector) Count() int { + d.mu.Lock() + defer d.mu.Unlock() + return len(d.dirents) +} + +// Contains checks whether the collector has a dirent with the given name and +// type. +func (d *DirentCollector) Contains(name string, typ uint8) error { + d.mu.Lock() + defer d.mu.Unlock() + dirent, ok := d.dirents[name] + if !ok { + return fmt.Errorf("No dirent named %q found", name) + } + if dirent.Type != typ { + return fmt.Errorf("Dirent named %q found, but was expecting type %s, got: %+v", name, linux.DirentType.Parse(uint64(typ)), dirent) + } + return nil +} + +// Dirents returns all dirents discovered by this collector. +func (d *DirentCollector) Dirents() map[string]*vfs.Dirent { + d.mu.Lock() + dirents := make(map[string]*vfs.Dirent) + for n, d := range d.dirents { + dirents[n] = d + } + d.mu.Unlock() + return dirents +} + +// OrderedDirents returns an ordered list of dirents as discovered by this +// collector. +func (d *DirentCollector) OrderedDirents() []*vfs.Dirent { + d.mu.Lock() + dirents := make([]*vfs.Dirent, len(d.order)) + copy(dirents, d.order) + d.mu.Unlock() + return dirents +} |