diff options
| -rw-r--r-- | pkg/sentry/vfs/BUILD | 3 | ||||
| -rw-r--r-- | pkg/sentry/vfs/anonfs.go | 259 | ||||
| -rw-r--r-- | pkg/sentry/vfs/file_description_impl_util_test.go | 18 | ||||
| -rw-r--r-- | pkg/sentry/vfs/testutil.go | 173 | ||||
| -rw-r--r-- | pkg/sentry/vfs/vfs.go | 24 |
5 files changed, 289 insertions, 188 deletions
diff --git a/pkg/sentry/vfs/BUILD b/pkg/sentry/vfs/BUILD index 6b1009328..33516e6f7 100644 --- a/pkg/sentry/vfs/BUILD +++ b/pkg/sentry/vfs/BUILD @@ -5,6 +5,7 @@ licenses(["notice"]) go_library( name = "vfs", srcs = [ + "anonfs.go", "context.go", "debug.go", "dentry.go", @@ -20,7 +21,6 @@ go_library( "pathname.go", "permissions.go", "resolving_path.go", - "testutil.go", "vfs.go", ], visibility = ["//pkg/sentry:internal"], @@ -50,7 +50,6 @@ go_test( "//pkg/abi/linux", "//pkg/context", "//pkg/sentry/contexttest", - "//pkg/sentry/kernel/auth", "//pkg/sync", "//pkg/syserror", "//pkg/usermem", diff --git a/pkg/sentry/vfs/anonfs.go b/pkg/sentry/vfs/anonfs.go new file mode 100644 index 000000000..2db25be49 --- /dev/null +++ b/pkg/sentry/vfs/anonfs.go @@ -0,0 +1,259 @@ +// Copyright 2020 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 vfs + +import ( + "fmt" + + "gvisor.dev/gvisor/pkg/abi/linux" + "gvisor.dev/gvisor/pkg/context" + "gvisor.dev/gvisor/pkg/fspath" + "gvisor.dev/gvisor/pkg/sentry/kernel/auth" + "gvisor.dev/gvisor/pkg/syserror" + "gvisor.dev/gvisor/pkg/usermem" +) + +// NewAnonVirtualDentry returns a VirtualDentry with the given synthetic name, +// consistent with Linux's fs/anon_inodes.c:anon_inode_getfile(). References +// are taken on the returned VirtualDentry. +func (vfs *VirtualFilesystem) NewAnonVirtualDentry(name string) VirtualDentry { + d := anonDentry{ + name: name, + } + d.vfsd.Init(&d) + vfs.anonMount.IncRef() + // anonDentry no-ops refcounting. + return VirtualDentry{ + mount: vfs.anonMount, + dentry: &d.vfsd, + } +} + +const anonfsBlockSize = usermem.PageSize // via fs/libfs.c:pseudo_fs_fill_super() + +// anonFilesystem is the implementation of FilesystemImpl that backs +// VirtualDentries returned by VirtualFilesystem.NewAnonVirtualDentry(). +// +// Since all Dentries in anonFilesystem are non-directories, all FilesystemImpl +// methods that would require an anonDentry to be a directory return ENOTDIR. +type anonFilesystem struct { + vfsfs Filesystem + + devMinor uint32 +} + +type anonDentry struct { + vfsd Dentry + + name string +} + +// Release implements FilesystemImpl.Release. +func (fs *anonFilesystem) Release() { +} + +// Sync implements FilesystemImpl.Sync. +func (fs *anonFilesystem) Sync(ctx context.Context) error { + return nil +} + +// GetDentryAt implements FilesystemImpl.GetDentryAt. +func (fs *anonFilesystem) GetDentryAt(ctx context.Context, rp *ResolvingPath, opts GetDentryOptions) (*Dentry, error) { + if !rp.Done() { + return nil, syserror.ENOTDIR + } + if opts.CheckSearchable { + return nil, syserror.ENOTDIR + } + // anonDentry no-ops refcounting. + return rp.Start(), nil +} + +// GetParentDentryAt implements FilesystemImpl.GetParentDentryAt. +func (fs *anonFilesystem) GetParentDentryAt(ctx context.Context, rp *ResolvingPath) (*Dentry, error) { + if !rp.Final() { + return nil, syserror.ENOTDIR + } + // anonDentry no-ops refcounting. + return rp.Start(), nil +} + +// LinkAt implements FilesystemImpl.LinkAt. +func (fs *anonFilesystem) LinkAt(ctx context.Context, rp *ResolvingPath, vd VirtualDentry) error { + if !rp.Final() { + return syserror.ENOTDIR + } + return syserror.EPERM +} + +// MkdirAt implements FilesystemImpl.MkdirAt. +func (fs *anonFilesystem) MkdirAt(ctx context.Context, rp *ResolvingPath, opts MkdirOptions) error { + if !rp.Final() { + return syserror.ENOTDIR + } + return syserror.EPERM +} + +// MknodAt implements FilesystemImpl.MknodAt. +func (fs *anonFilesystem) MknodAt(ctx context.Context, rp *ResolvingPath, opts MknodOptions) error { + if !rp.Final() { + return syserror.ENOTDIR + } + return syserror.EPERM +} + +// OpenAt implements FilesystemImpl.OpenAt. +func (fs *anonFilesystem) OpenAt(ctx context.Context, rp *ResolvingPath, opts OpenOptions) (*FileDescription, error) { + if !rp.Done() { + return nil, syserror.ENOTDIR + } + return nil, syserror.ENODEV +} + +// ReadlinkAt implements FilesystemImpl.ReadlinkAt. +func (fs *anonFilesystem) ReadlinkAt(ctx context.Context, rp *ResolvingPath) (string, error) { + if !rp.Done() { + return "", syserror.ENOTDIR + } + return "", syserror.EINVAL +} + +// RenameAt implements FilesystemImpl.RenameAt. +func (fs *anonFilesystem) RenameAt(ctx context.Context, rp *ResolvingPath, oldParentVD VirtualDentry, oldName string, opts RenameOptions) error { + if !rp.Final() { + return syserror.ENOTDIR + } + return syserror.EPERM +} + +// RmdirAt implements FilesystemImpl.RmdirAt. +func (fs *anonFilesystem) RmdirAt(ctx context.Context, rp *ResolvingPath) error { + if !rp.Final() { + return syserror.ENOTDIR + } + return syserror.EPERM +} + +// SetStatAt implements FilesystemImpl.SetStatAt. +func (fs *anonFilesystem) SetStatAt(ctx context.Context, rp *ResolvingPath, opts SetStatOptions) error { + if !rp.Done() { + return syserror.ENOTDIR + } + // Linux actually permits anon_inode_inode's metadata to be set, which is + // visible to all users of anon_inode_inode. We just silently ignore + // metadata changes. + return nil +} + +// StatAt implements FilesystemImpl.StatAt. +func (fs *anonFilesystem) StatAt(ctx context.Context, rp *ResolvingPath, opts StatOptions) (linux.Statx, error) { + if !rp.Done() { + return linux.Statx{}, syserror.ENOTDIR + } + // See fs/anon_inodes.c:anon_inode_init() => fs/libfs.c:alloc_anon_inode(). + return linux.Statx{ + Mask: linux.STATX_TYPE | linux.STATX_MODE | linux.STATX_NLINK | linux.STATX_UID | linux.STATX_GID | linux.STATX_INO | linux.STATX_SIZE | linux.STATX_BLOCKS, + Blksize: anonfsBlockSize, + Nlink: 1, + UID: uint32(auth.RootKUID), + GID: uint32(auth.RootKGID), + Mode: 0600, // no type is correct + Ino: 1, + Size: 0, + Blocks: 0, + DevMajor: 0, + DevMinor: fs.devMinor, + }, nil +} + +// StatFSAt implements FilesystemImpl.StatFSAt. +func (fs *anonFilesystem) StatFSAt(ctx context.Context, rp *ResolvingPath) (linux.Statfs, error) { + if !rp.Done() { + return linux.Statfs{}, syserror.ENOTDIR + } + return linux.Statfs{ + Type: linux.ANON_INODE_FS_MAGIC, + BlockSize: anonfsBlockSize, + }, nil +} + +// SymlinkAt implements FilesystemImpl.SymlinkAt. +func (fs *anonFilesystem) SymlinkAt(ctx context.Context, rp *ResolvingPath, target string) error { + if !rp.Final() { + return syserror.ENOTDIR + } + return syserror.EPERM +} + +// UnlinkAt implements FilesystemImpl.UnlinkAt. +func (fs *anonFilesystem) UnlinkAt(ctx context.Context, rp *ResolvingPath) error { + if !rp.Final() { + return syserror.ENOTDIR + } + return syserror.EPERM +} + +// ListxattrAt implements FilesystemImpl.ListxattrAt. +func (fs *anonFilesystem) ListxattrAt(ctx context.Context, rp *ResolvingPath) ([]string, error) { + if !rp.Done() { + return nil, syserror.ENOTDIR + } + return nil, nil +} + +// GetxattrAt implements FilesystemImpl.GetxattrAt. +func (fs *anonFilesystem) GetxattrAt(ctx context.Context, rp *ResolvingPath, name string) (string, error) { + if !rp.Done() { + return "", syserror.ENOTDIR + } + return "", syserror.ENOTSUP +} + +// SetxattrAt implements FilesystemImpl.SetxattrAt. +func (fs *anonFilesystem) SetxattrAt(ctx context.Context, rp *ResolvingPath, opts SetxattrOptions) error { + if !rp.Done() { + return syserror.ENOTDIR + } + return syserror.EPERM +} + +// RemovexattrAt implements FilesystemImpl.RemovexattrAt. +func (fs *anonFilesystem) RemovexattrAt(ctx context.Context, rp *ResolvingPath, name string) error { + if !rp.Done() { + return syserror.ENOTDIR + } + return syserror.EPERM +} + +// PrependPath implements FilesystemImpl.PrependPath. +func (fs *anonFilesystem) PrependPath(ctx context.Context, vfsroot, vd VirtualDentry, b *fspath.Builder) error { + b.PrependComponent(fmt.Sprintf("anon_inode:%s", vd.dentry.impl.(*anonDentry).name)) + return PrependPathSyntheticError{} +} + +// IncRef implements DentryImpl.IncRef. +func (d *anonDentry) IncRef() { + // no-op +} + +// TryIncRef implements DentryImpl.TryIncRef. +func (d *anonDentry) TryIncRef() bool { + return true +} + +// DecRef implements DentryImpl.DecRef. +func (d *anonDentry) DecRef() { + // no-op +} diff --git a/pkg/sentry/vfs/file_description_impl_util_test.go b/pkg/sentry/vfs/file_description_impl_util_test.go index 1720d325d..0f44e7c8c 100644 --- a/pkg/sentry/vfs/file_description_impl_util_test.go +++ b/pkg/sentry/vfs/file_description_impl_util_test.go @@ -24,7 +24,6 @@ import ( "gvisor.dev/gvisor/pkg/abi/linux" "gvisor.dev/gvisor/pkg/context" "gvisor.dev/gvisor/pkg/sentry/contexttest" - "gvisor.dev/gvisor/pkg/sentry/kernel/auth" "gvisor.dev/gvisor/pkg/syserror" "gvisor.dev/gvisor/pkg/usermem" ) @@ -46,9 +45,11 @@ type genCountFD struct { count uint64 // accessed using atomic memory ops } -func newGenCountFD(mnt *Mount, vfsd *Dentry) *FileDescription { +func newGenCountFD(vfsObj *VirtualFilesystem) *FileDescription { + vd := vfsObj.NewAnonVirtualDentry("genCountFD") + defer vd.DecRef() var fd genCountFD - fd.vfsfd.Init(&fd, 0 /* statusFlags */, mnt, vfsd, &FileDescriptionOptions{}) + fd.vfsfd.Init(&fd, 0 /* statusFlags */, vd.Mount(), vd.Dentry(), &FileDescriptionOptions{}) fd.DynamicBytesFileDescriptionImpl.SetDataSource(&fd) return &fd.vfsfd } @@ -86,18 +87,9 @@ func (fd *genCountFD) Generate(ctx context.Context, buf *bytes.Buffer) error { func TestGenCountFD(t *testing.T) { ctx := contexttest.Context(t) - creds := auth.CredentialsFromContext(ctx) vfsObj := New() // vfs.New() - vfsObj.MustRegisterFilesystemType("testfs", FDTestFilesystemType{}, &RegisterFilesystemTypeOptions{}) - mntns, err := vfsObj.NewMountNamespace(ctx, creds, "", "testfs", &GetFilesystemOptions{}) - if err != nil { - t.Fatalf("failed to create testfs root mount: %v", err) - } - vd := mntns.Root() - defer vd.DecRef() - - fd := newGenCountFD(vd.Mount(), vd.Dentry()) + fd := newGenCountFD(vfsObj) defer fd.DecRef() // The first read causes Generate to be called to fill the FD's buffer. diff --git a/pkg/sentry/vfs/testutil.go b/pkg/sentry/vfs/testutil.go deleted file mode 100644 index 392c7611e..000000000 --- a/pkg/sentry/vfs/testutil.go +++ /dev/null @@ -1,173 +0,0 @@ -// 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 vfs - -import ( - "fmt" - - "gvisor.dev/gvisor/pkg/abi/linux" - "gvisor.dev/gvisor/pkg/context" - "gvisor.dev/gvisor/pkg/fspath" - "gvisor.dev/gvisor/pkg/sentry/kernel/auth" - "gvisor.dev/gvisor/pkg/syserror" -) - -// FDTestFilesystemType is a test-only FilesystemType that produces Filesystems -// for which all FilesystemImpl methods taking a path return EPERM. It is used -// to produce Mounts and Dentries for testing of FileDescriptionImpls that do -// not depend on their originating Filesystem. -type FDTestFilesystemType struct{} - -// FDTestFilesystem is a test-only FilesystemImpl produced by -// FDTestFilesystemType. -type FDTestFilesystem struct { - vfsfs Filesystem -} - -// GetFilesystem implements FilesystemType.GetFilesystem. -func (fstype FDTestFilesystemType) GetFilesystem(ctx context.Context, vfsObj *VirtualFilesystem, creds *auth.Credentials, source string, opts GetFilesystemOptions) (*Filesystem, *Dentry, error) { - var fs FDTestFilesystem - fs.vfsfs.Init(vfsObj, &fs) - return &fs.vfsfs, fs.NewDentry(), nil -} - -// Release implements FilesystemImpl.Release. -func (fs *FDTestFilesystem) Release() { -} - -// Sync implements FilesystemImpl.Sync. -func (fs *FDTestFilesystem) Sync(ctx context.Context) error { - return nil -} - -// GetDentryAt implements FilesystemImpl.GetDentryAt. -func (fs *FDTestFilesystem) GetDentryAt(ctx context.Context, rp *ResolvingPath, opts GetDentryOptions) (*Dentry, error) { - return nil, syserror.EPERM -} - -// GetParentDentryAt implements FilesystemImpl.GetParentDentryAt. -func (fs *FDTestFilesystem) GetParentDentryAt(ctx context.Context, rp *ResolvingPath) (*Dentry, error) { - return nil, syserror.EPERM -} - -// LinkAt implements FilesystemImpl.LinkAt. -func (fs *FDTestFilesystem) LinkAt(ctx context.Context, rp *ResolvingPath, vd VirtualDentry) error { - return syserror.EPERM -} - -// MkdirAt implements FilesystemImpl.MkdirAt. -func (fs *FDTestFilesystem) MkdirAt(ctx context.Context, rp *ResolvingPath, opts MkdirOptions) error { - return syserror.EPERM -} - -// MknodAt implements FilesystemImpl.MknodAt. -func (fs *FDTestFilesystem) MknodAt(ctx context.Context, rp *ResolvingPath, opts MknodOptions) error { - return syserror.EPERM -} - -// OpenAt implements FilesystemImpl.OpenAt. -func (fs *FDTestFilesystem) OpenAt(ctx context.Context, rp *ResolvingPath, opts OpenOptions) (*FileDescription, error) { - return nil, syserror.EPERM -} - -// ReadlinkAt implements FilesystemImpl.ReadlinkAt. -func (fs *FDTestFilesystem) ReadlinkAt(ctx context.Context, rp *ResolvingPath) (string, error) { - return "", syserror.EPERM -} - -// RenameAt implements FilesystemImpl.RenameAt. -func (fs *FDTestFilesystem) RenameAt(ctx context.Context, rp *ResolvingPath, oldParentVD VirtualDentry, oldName string, opts RenameOptions) error { - return syserror.EPERM -} - -// RmdirAt implements FilesystemImpl.RmdirAt. -func (fs *FDTestFilesystem) RmdirAt(ctx context.Context, rp *ResolvingPath) error { - return syserror.EPERM -} - -// SetStatAt implements FilesystemImpl.SetStatAt. -func (fs *FDTestFilesystem) SetStatAt(ctx context.Context, rp *ResolvingPath, opts SetStatOptions) error { - return syserror.EPERM -} - -// StatAt implements FilesystemImpl.StatAt. -func (fs *FDTestFilesystem) StatAt(ctx context.Context, rp *ResolvingPath, opts StatOptions) (linux.Statx, error) { - return linux.Statx{}, syserror.EPERM -} - -// StatFSAt implements FilesystemImpl.StatFSAt. -func (fs *FDTestFilesystem) StatFSAt(ctx context.Context, rp *ResolvingPath) (linux.Statfs, error) { - return linux.Statfs{}, syserror.EPERM -} - -// SymlinkAt implements FilesystemImpl.SymlinkAt. -func (fs *FDTestFilesystem) SymlinkAt(ctx context.Context, rp *ResolvingPath, target string) error { - return syserror.EPERM -} - -// UnlinkAt implements FilesystemImpl.UnlinkAt. -func (fs *FDTestFilesystem) UnlinkAt(ctx context.Context, rp *ResolvingPath) error { - return syserror.EPERM -} - -// ListxattrAt implements FilesystemImpl.ListxattrAt. -func (fs *FDTestFilesystem) ListxattrAt(ctx context.Context, rp *ResolvingPath) ([]string, error) { - return nil, syserror.EPERM -} - -// GetxattrAt implements FilesystemImpl.GetxattrAt. -func (fs *FDTestFilesystem) GetxattrAt(ctx context.Context, rp *ResolvingPath, name string) (string, error) { - return "", syserror.EPERM -} - -// SetxattrAt implements FilesystemImpl.SetxattrAt. -func (fs *FDTestFilesystem) SetxattrAt(ctx context.Context, rp *ResolvingPath, opts SetxattrOptions) error { - return syserror.EPERM -} - -// RemovexattrAt implements FilesystemImpl.RemovexattrAt. -func (fs *FDTestFilesystem) RemovexattrAt(ctx context.Context, rp *ResolvingPath, name string) error { - return syserror.EPERM -} - -// PrependPath implements FilesystemImpl.PrependPath. -func (fs *FDTestFilesystem) PrependPath(ctx context.Context, vfsroot, vd VirtualDentry, b *fspath.Builder) error { - b.PrependComponent(fmt.Sprintf("vfs.fdTestDentry:%p", vd.dentry.impl.(*fdTestDentry))) - return PrependPathSyntheticError{} -} - -type fdTestDentry struct { - vfsd Dentry -} - -// NewDentry returns a new Dentry. -func (fs *FDTestFilesystem) NewDentry() *Dentry { - var d fdTestDentry - d.vfsd.Init(&d) - return &d.vfsd -} - -// IncRef implements DentryImpl.IncRef. -func (d *fdTestDentry) IncRef() { -} - -// TryIncRef implements DentryImpl.TryIncRef. -func (d *fdTestDentry) TryIncRef() bool { - return true -} - -// DecRef implements DentryImpl.DecRef. -func (d *fdTestDentry) DecRef() { -} diff --git a/pkg/sentry/vfs/vfs.go b/pkg/sentry/vfs/vfs.go index b2bf48853..d730530b9 100644 --- a/pkg/sentry/vfs/vfs.go +++ b/pkg/sentry/vfs/vfs.go @@ -75,6 +75,14 @@ type VirtualFilesystem struct { // mountpoints is analogous to Linux's mountpoint_hashtable. mountpoints map[*Dentry]map[*Mount]struct{} + // anonMount is a Mount, not included in mounts or mountpoints, + // representing an anonFilesystem. anonMount is used to back + // VirtualDentries returned by VirtualFilesystem.NewAnonVirtualDentry(). + // anonMount is immutable. + // + // anonMount is analogous to Linux's anon_inode_mnt. + anonMount *Mount + // devices contains all registered Devices. devices is protected by // devicesMu. devicesMu sync.RWMutex @@ -110,6 +118,22 @@ func New() *VirtualFilesystem { filesystems: make(map[*Filesystem]struct{}), } vfs.mounts.Init() + + // Construct vfs.anonMount. + anonfsDevMinor, err := vfs.GetAnonBlockDevMinor() + if err != nil { + panic(fmt.Sprintf("VirtualFilesystem.GetAnonBlockDevMinor() failed during VirtualFilesystem construction: %v", err)) + } + anonfs := anonFilesystem{ + devMinor: anonfsDevMinor, + } + anonfs.vfsfs.Init(vfs, &anonfs) + vfs.anonMount = &Mount{ + vfs: vfs, + fs: &anonfs.vfsfs, + refs: 1, + } + return vfs } |