diff options
Diffstat (limited to 'pkg/sentry/fs')
40 files changed, 792 insertions, 249 deletions
diff --git a/pkg/sentry/fs/copy_up.go b/pkg/sentry/fs/copy_up.go index f6c79e51b..b060a12ff 100644 --- a/pkg/sentry/fs/copy_up.go +++ b/pkg/sentry/fs/copy_up.go @@ -401,7 +401,7 @@ func copyAttributesLocked(ctx context.Context, upper *Inode, lower *Inode) error if err != nil { return err } - lowerXattr, err := lower.ListXattr(ctx) + lowerXattr, err := lower.ListXattr(ctx, linux.XATTR_SIZE_MAX) if err != nil && err != syserror.EOPNOTSUPP { return err } diff --git a/pkg/sentry/fs/dev/BUILD b/pkg/sentry/fs/dev/BUILD index 4c4b7d5cc..9379a4d7b 100644 --- a/pkg/sentry/fs/dev/BUILD +++ b/pkg/sentry/fs/dev/BUILD @@ -9,6 +9,7 @@ go_library( "device.go", "fs.go", "full.go", + "net_tun.go", "null.go", "random.go", "tty.go", @@ -19,15 +20,20 @@ go_library( "//pkg/context", "//pkg/rand", "//pkg/safemem", + "//pkg/sentry/arch", "//pkg/sentry/device", "//pkg/sentry/fs", "//pkg/sentry/fs/fsutil", "//pkg/sentry/fs/ramfs", "//pkg/sentry/fs/tmpfs", + "//pkg/sentry/inet", + "//pkg/sentry/kernel", "//pkg/sentry/memmap", "//pkg/sentry/mm", "//pkg/sentry/pgalloc", + "//pkg/sentry/socket/netstack", "//pkg/syserror", + "//pkg/tcpip/link/tun", "//pkg/usermem", "//pkg/waiter", ], diff --git a/pkg/sentry/fs/dev/dev.go b/pkg/sentry/fs/dev/dev.go index 35bd23991..acbd401a0 100644 --- a/pkg/sentry/fs/dev/dev.go +++ b/pkg/sentry/fs/dev/dev.go @@ -22,6 +22,7 @@ import ( "gvisor.dev/gvisor/pkg/sentry/fs" "gvisor.dev/gvisor/pkg/sentry/fs/ramfs" "gvisor.dev/gvisor/pkg/sentry/fs/tmpfs" + "gvisor.dev/gvisor/pkg/sentry/inet" "gvisor.dev/gvisor/pkg/usermem" ) @@ -66,8 +67,8 @@ func newMemDevice(ctx context.Context, iops fs.InodeOperations, msrc *fs.MountSo }) } -func newDirectory(ctx context.Context, msrc *fs.MountSource) *fs.Inode { - iops := ramfs.NewDir(ctx, nil, fs.RootOwner, fs.FilePermsFromMode(0555)) +func newDirectory(ctx context.Context, contents map[string]*fs.Inode, msrc *fs.MountSource) *fs.Inode { + iops := ramfs.NewDir(ctx, contents, fs.RootOwner, fs.FilePermsFromMode(0555)) return fs.NewInode(ctx, iops, msrc, fs.StableAttr{ DeviceID: devDevice.DeviceID(), InodeID: devDevice.NextIno(), @@ -111,7 +112,7 @@ func New(ctx context.Context, msrc *fs.MountSource) *fs.Inode { // A devpts is typically mounted at /dev/pts to provide // pseudoterminal support. Place an empty directory there for // the devpts to be mounted over. - "pts": newDirectory(ctx, msrc), + "pts": newDirectory(ctx, nil, msrc), // Similarly, applications expect a ptmx device at /dev/ptmx // connected to the terminals provided by /dev/pts/. Rather // than creating a device directly (which requires a hairy @@ -126,6 +127,12 @@ func New(ctx context.Context, msrc *fs.MountSource) *fs.Inode { "tty": newCharacterDevice(ctx, newTTYDevice(ctx, fs.RootOwner, 0666), msrc, ttyDevMajor, ttyDevMinor), } + if isNetTunSupported(inet.StackFromContext(ctx)) { + contents["net"] = newDirectory(ctx, map[string]*fs.Inode{ + "tun": newCharacterDevice(ctx, newNetTunDevice(ctx, fs.RootOwner, 0666), msrc, netTunDevMajor, netTunDevMinor), + }, msrc) + } + iops := ramfs.NewDir(ctx, contents, fs.RootOwner, fs.FilePermsFromMode(0555)) return fs.NewInode(ctx, iops, msrc, fs.StableAttr{ DeviceID: devDevice.DeviceID(), diff --git a/pkg/sentry/fs/dev/net_tun.go b/pkg/sentry/fs/dev/net_tun.go new file mode 100644 index 000000000..dc7ad075a --- /dev/null +++ b/pkg/sentry/fs/dev/net_tun.go @@ -0,0 +1,177 @@ +// 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 dev + +import ( + "gvisor.dev/gvisor/pkg/abi/linux" + "gvisor.dev/gvisor/pkg/context" + "gvisor.dev/gvisor/pkg/sentry/arch" + "gvisor.dev/gvisor/pkg/sentry/fs" + "gvisor.dev/gvisor/pkg/sentry/fs/fsutil" + "gvisor.dev/gvisor/pkg/sentry/inet" + "gvisor.dev/gvisor/pkg/sentry/kernel" + "gvisor.dev/gvisor/pkg/sentry/socket/netstack" + "gvisor.dev/gvisor/pkg/syserror" + "gvisor.dev/gvisor/pkg/tcpip/link/tun" + "gvisor.dev/gvisor/pkg/usermem" + "gvisor.dev/gvisor/pkg/waiter" +) + +const ( + netTunDevMajor = 10 + netTunDevMinor = 200 +) + +// +stateify savable +type netTunInodeOperations struct { + fsutil.InodeGenericChecker `state:"nosave"` + fsutil.InodeNoExtendedAttributes `state:"nosave"` + fsutil.InodeNoopAllocate `state:"nosave"` + fsutil.InodeNoopRelease `state:"nosave"` + fsutil.InodeNoopTruncate `state:"nosave"` + fsutil.InodeNoopWriteOut `state:"nosave"` + fsutil.InodeNotDirectory `state:"nosave"` + fsutil.InodeNotMappable `state:"nosave"` + fsutil.InodeNotSocket `state:"nosave"` + fsutil.InodeNotSymlink `state:"nosave"` + fsutil.InodeVirtual `state:"nosave"` + + fsutil.InodeSimpleAttributes +} + +var _ fs.InodeOperations = (*netTunInodeOperations)(nil) + +func newNetTunDevice(ctx context.Context, owner fs.FileOwner, mode linux.FileMode) *netTunInodeOperations { + return &netTunInodeOperations{ + InodeSimpleAttributes: fsutil.NewInodeSimpleAttributes(ctx, owner, fs.FilePermsFromMode(mode), linux.TMPFS_MAGIC), + } +} + +// GetFile implements fs.InodeOperations.GetFile. +func (iops *netTunInodeOperations) GetFile(ctx context.Context, d *fs.Dirent, flags fs.FileFlags) (*fs.File, error) { + return fs.NewFile(ctx, d, flags, &netTunFileOperations{}), nil +} + +// +stateify savable +type netTunFileOperations struct { + fsutil.FileNoSeek `state:"nosave"` + fsutil.FileNoMMap `state:"nosave"` + fsutil.FileNoSplice `state:"nosave"` + fsutil.FileNoopFlush `state:"nosave"` + fsutil.FileNoopFsync `state:"nosave"` + fsutil.FileNotDirReaddir `state:"nosave"` + fsutil.FileUseInodeUnstableAttr `state:"nosave"` + + device tun.Device +} + +var _ fs.FileOperations = (*netTunFileOperations)(nil) + +// Release implements fs.FileOperations.Release. +func (fops *netTunFileOperations) Release() { + fops.device.Release() +} + +// Ioctl implements fs.FileOperations.Ioctl. +func (fops *netTunFileOperations) Ioctl(ctx context.Context, file *fs.File, io usermem.IO, args arch.SyscallArguments) (uintptr, error) { + request := args[1].Uint() + data := args[2].Pointer() + + switch request { + case linux.TUNSETIFF: + t := kernel.TaskFromContext(ctx) + if t == nil { + panic("Ioctl should be called from a task context") + } + if !t.HasCapability(linux.CAP_NET_ADMIN) { + return 0, syserror.EPERM + } + stack, ok := t.NetworkContext().(*netstack.Stack) + if !ok { + return 0, syserror.EINVAL + } + + var req linux.IFReq + if _, err := usermem.CopyObjectIn(ctx, io, data, &req, usermem.IOOpts{ + AddressSpaceActive: true, + }); err != nil { + return 0, err + } + flags := usermem.ByteOrder.Uint16(req.Data[:]) + return 0, fops.device.SetIff(stack.Stack, req.Name(), flags) + + case linux.TUNGETIFF: + var req linux.IFReq + + copy(req.IFName[:], fops.device.Name()) + + // Linux adds IFF_NOFILTER (the same value as IFF_NO_PI unfortunately) when + // there is no sk_filter. See __tun_chr_ioctl() in net/drivers/tun.c. + flags := fops.device.Flags() | linux.IFF_NOFILTER + usermem.ByteOrder.PutUint16(req.Data[:], flags) + + _, err := usermem.CopyObjectOut(ctx, io, data, &req, usermem.IOOpts{ + AddressSpaceActive: true, + }) + return 0, err + + default: + return 0, syserror.ENOTTY + } +} + +// Write implements fs.FileOperations.Write. +func (fops *netTunFileOperations) Write(ctx context.Context, file *fs.File, src usermem.IOSequence, offset int64) (int64, error) { + data := make([]byte, src.NumBytes()) + if _, err := src.CopyIn(ctx, data); err != nil { + return 0, err + } + return fops.device.Write(data) +} + +// Read implements fs.FileOperations.Read. +func (fops *netTunFileOperations) Read(ctx context.Context, file *fs.File, dst usermem.IOSequence, offset int64) (int64, error) { + data, err := fops.device.Read() + if err != nil { + return 0, err + } + n, err := dst.CopyOut(ctx, data) + if n > 0 && n < len(data) { + // Not an error for partial copying. Packet truncated. + err = nil + } + return int64(n), err +} + +// Readiness implements watier.Waitable.Readiness. +func (fops *netTunFileOperations) Readiness(mask waiter.EventMask) waiter.EventMask { + return fops.device.Readiness(mask) +} + +// EventRegister implements watier.Waitable.EventRegister. +func (fops *netTunFileOperations) EventRegister(e *waiter.Entry, mask waiter.EventMask) { + fops.device.EventRegister(e, mask) +} + +// EventUnregister implements watier.Waitable.EventUnregister. +func (fops *netTunFileOperations) EventUnregister(e *waiter.Entry) { + fops.device.EventUnregister(e) +} + +// isNetTunSupported returns whether /dev/net/tun device is supported for s. +func isNetTunSupported(s inet.Stack) bool { + _, ok := s.(*netstack.Stack) + return ok +} diff --git a/pkg/sentry/fs/dirent.go b/pkg/sentry/fs/dirent.go index acab0411a..e0b32e1c1 100644 --- a/pkg/sentry/fs/dirent.go +++ b/pkg/sentry/fs/dirent.go @@ -1438,8 +1438,8 @@ func lockForRename(oldParent *Dirent, oldName string, newParent *Dirent, newName }, nil } -func checkSticky(ctx context.Context, dir *Dirent, victim *Dirent) error { - uattr, err := dir.Inode.UnstableAttr(ctx) +func (d *Dirent) checkSticky(ctx context.Context, victim *Dirent) error { + uattr, err := d.Inode.UnstableAttr(ctx) if err != nil { return syserror.EPERM } @@ -1465,30 +1465,33 @@ func checkSticky(ctx context.Context, dir *Dirent, victim *Dirent) error { return syserror.EPERM } -// MayDelete determines whether `name`, a child of `dir`, can be deleted or +// MayDelete determines whether `name`, a child of `d`, can be deleted or // renamed by `ctx`. // // Compare Linux kernel fs/namei.c:may_delete. -func MayDelete(ctx context.Context, root, dir *Dirent, name string) error { - if err := dir.Inode.CheckPermission(ctx, PermMask{Write: true, Execute: true}); err != nil { +func (d *Dirent) MayDelete(ctx context.Context, root *Dirent, name string) error { + if err := d.Inode.CheckPermission(ctx, PermMask{Write: true, Execute: true}); err != nil { return err } - victim, err := dir.Walk(ctx, root, name) + unlock := d.lockDirectory() + defer unlock() + + victim, err := d.walk(ctx, root, name, true /* may unlock */) if err != nil { return err } defer victim.DecRef() - return mayDelete(ctx, dir, victim) + return d.mayDelete(ctx, victim) } // mayDelete determines whether `victim`, a child of `dir`, can be deleted or // renamed by `ctx`. // // Preconditions: `dir` is writable and executable by `ctx`. -func mayDelete(ctx context.Context, dir, victim *Dirent) error { - if err := checkSticky(ctx, dir, victim); err != nil { +func (d *Dirent) mayDelete(ctx context.Context, victim *Dirent) error { + if err := d.checkSticky(ctx, victim); err != nil { return err } @@ -1542,7 +1545,7 @@ func Rename(ctx context.Context, root *Dirent, oldParent *Dirent, oldName string defer renamed.DecRef() // Check that the renamed dirent is deletable. - if err := mayDelete(ctx, oldParent, renamed); err != nil { + if err := oldParent.mayDelete(ctx, renamed); err != nil { return err } @@ -1580,7 +1583,7 @@ func Rename(ctx context.Context, root *Dirent, oldParent *Dirent, oldName string // across the Rename, so must call DecRef manually (no defer). // Check that we can delete replaced. - if err := mayDelete(ctx, newParent, replaced); err != nil { + if err := newParent.mayDelete(ctx, replaced); err != nil { replaced.DecRef() return err } diff --git a/pkg/sentry/fs/dirent_cache.go b/pkg/sentry/fs/dirent_cache.go index 25514ace4..33de32c69 100644 --- a/pkg/sentry/fs/dirent_cache.go +++ b/pkg/sentry/fs/dirent_cache.go @@ -101,8 +101,6 @@ func (c *DirentCache) remove(d *Dirent) { panic(fmt.Sprintf("trying to remove %v, which is not in the dirent cache", d)) } c.list.Remove(d) - d.SetPrev(nil) - d.SetNext(nil) d.DecRef() c.currentSize-- if c.limit != nil { diff --git a/pkg/sentry/fs/file_overlay_test.go b/pkg/sentry/fs/file_overlay_test.go index 02538bb4f..a76d87e3a 100644 --- a/pkg/sentry/fs/file_overlay_test.go +++ b/pkg/sentry/fs/file_overlay_test.go @@ -177,6 +177,7 @@ func TestReaddirRevalidation(t *testing.T) { // TestReaddirOverlayFrozen tests that calling Readdir on an overlay file with // a frozen dirent tree does not make Readdir calls to the underlying files. +// This is a regression test for b/114808269. func TestReaddirOverlayFrozen(t *testing.T) { ctx := contexttest.Context(t) diff --git a/pkg/sentry/fs/fsutil/BUILD b/pkg/sentry/fs/fsutil/BUILD index 4ab2a384f..789369220 100644 --- a/pkg/sentry/fs/fsutil/BUILD +++ b/pkg/sentry/fs/fsutil/BUILD @@ -28,13 +28,13 @@ go_template_instance( "platform": "gvisor.dev/gvisor/pkg/sentry/platform", }, package = "fsutil", - prefix = "frameRef", + prefix = "FrameRef", template = "//pkg/segment:generic_set", types = { "Key": "uint64", "Range": "platform.FileRange", "Value": "uint64", - "Functions": "frameRefSetFunctions", + "Functions": "FrameRefSetFunctions", }, ) diff --git a/pkg/sentry/fs/fsutil/frame_ref_set.go b/pkg/sentry/fs/fsutil/frame_ref_set.go index dd63db32b..6564fd0c6 100644 --- a/pkg/sentry/fs/fsutil/frame_ref_set.go +++ b/pkg/sentry/fs/fsutil/frame_ref_set.go @@ -20,24 +20,25 @@ import ( "gvisor.dev/gvisor/pkg/sentry/platform" ) -type frameRefSetFunctions struct{} +// FrameRefSetFunctions implements segment.Functions for FrameRefSet. +type FrameRefSetFunctions struct{} // MinKey implements segment.Functions.MinKey. -func (frameRefSetFunctions) MinKey() uint64 { +func (FrameRefSetFunctions) MinKey() uint64 { return 0 } // MaxKey implements segment.Functions.MaxKey. -func (frameRefSetFunctions) MaxKey() uint64 { +func (FrameRefSetFunctions) MaxKey() uint64 { return math.MaxUint64 } // ClearValue implements segment.Functions.ClearValue. -func (frameRefSetFunctions) ClearValue(val *uint64) { +func (FrameRefSetFunctions) ClearValue(val *uint64) { } // Merge implements segment.Functions.Merge. -func (frameRefSetFunctions) Merge(_ platform.FileRange, val1 uint64, _ platform.FileRange, val2 uint64) (uint64, bool) { +func (FrameRefSetFunctions) Merge(_ platform.FileRange, val1 uint64, _ platform.FileRange, val2 uint64) (uint64, bool) { if val1 != val2 { return 0, false } @@ -45,6 +46,6 @@ func (frameRefSetFunctions) Merge(_ platform.FileRange, val1 uint64, _ platform. } // Split implements segment.Functions.Split. -func (frameRefSetFunctions) Split(_ platform.FileRange, val uint64, _ uint64) (uint64, uint64) { +func (FrameRefSetFunctions) Split(_ platform.FileRange, val uint64, _ uint64) (uint64, uint64) { return val, val } diff --git a/pkg/sentry/fs/fsutil/host_file_mapper.go b/pkg/sentry/fs/fsutil/host_file_mapper.go index 67278aa86..e82afd112 100644 --- a/pkg/sentry/fs/fsutil/host_file_mapper.go +++ b/pkg/sentry/fs/fsutil/host_file_mapper.go @@ -65,13 +65,18 @@ type mapping struct { writable bool } -// NewHostFileMapper returns a HostFileMapper with no references or cached -// mappings. +// Init must be called on zero-value HostFileMappers before first use. +func (f *HostFileMapper) Init() { + f.refs = make(map[uint64]int32) + f.mappings = make(map[uint64]mapping) +} + +// NewHostFileMapper returns an initialized HostFileMapper allocated on the +// heap with no references or cached mappings. func NewHostFileMapper() *HostFileMapper { - return &HostFileMapper{ - refs: make(map[uint64]int32), - mappings: make(map[uint64]mapping), - } + f := &HostFileMapper{} + f.Init() + return f } // IncRefOn increments the reference count on all offsets in mr. diff --git a/pkg/sentry/fs/fsutil/inode.go b/pkg/sentry/fs/fsutil/inode.go index 252830572..1922ff08c 100644 --- a/pkg/sentry/fs/fsutil/inode.go +++ b/pkg/sentry/fs/fsutil/inode.go @@ -247,7 +247,7 @@ func (i *InodeSimpleExtendedAttributes) SetXattr(_ context.Context, _ *fs.Inode, } // ListXattr implements fs.InodeOperations.ListXattr. -func (i *InodeSimpleExtendedAttributes) ListXattr(context.Context, *fs.Inode) (map[string]struct{}, error) { +func (i *InodeSimpleExtendedAttributes) ListXattr(context.Context, *fs.Inode, uint64) (map[string]struct{}, error) { i.mu.RLock() names := make(map[string]struct{}, len(i.xattrs)) for name := range i.xattrs { @@ -257,6 +257,17 @@ func (i *InodeSimpleExtendedAttributes) ListXattr(context.Context, *fs.Inode) (m return names, nil } +// RemoveXattr implements fs.InodeOperations.RemoveXattr. +func (i *InodeSimpleExtendedAttributes) RemoveXattr(_ context.Context, _ *fs.Inode, name string) error { + i.mu.Lock() + defer i.mu.Unlock() + if _, ok := i.xattrs[name]; ok { + delete(i.xattrs, name) + return nil + } + return syserror.ENOATTR +} + // staticFile is a file with static contents. It is returned by // InodeStaticFileGetter.GetFile. // @@ -460,10 +471,15 @@ func (InodeNoExtendedAttributes) SetXattr(context.Context, *fs.Inode, string, st } // ListXattr implements fs.InodeOperations.ListXattr. -func (InodeNoExtendedAttributes) ListXattr(context.Context, *fs.Inode) (map[string]struct{}, error) { +func (InodeNoExtendedAttributes) ListXattr(context.Context, *fs.Inode, uint64) (map[string]struct{}, error) { return nil, syserror.EOPNOTSUPP } +// RemoveXattr implements fs.InodeOperations.RemoveXattr. +func (InodeNoExtendedAttributes) RemoveXattr(context.Context, *fs.Inode, string) error { + return syserror.EOPNOTSUPP +} + // InodeNoopRelease implements fs.InodeOperations.Release as a noop. type InodeNoopRelease struct{} diff --git a/pkg/sentry/fs/fsutil/inode_cached.go b/pkg/sentry/fs/fsutil/inode_cached.go index 573b8586e..800c8b4e1 100644 --- a/pkg/sentry/fs/fsutil/inode_cached.go +++ b/pkg/sentry/fs/fsutil/inode_cached.go @@ -111,7 +111,7 @@ type CachingInodeOperations struct { // refs tracks active references to data in the cache. // // refs is protected by dataMu. - refs frameRefSet + refs FrameRefSet } // CachingInodeOperationsOptions configures a CachingInodeOperations. diff --git a/pkg/sentry/fs/g3doc/inotify.md b/pkg/sentry/fs/g3doc/inotify.md index 71a577d9d..85063d4e6 100644 --- a/pkg/sentry/fs/g3doc/inotify.md +++ b/pkg/sentry/fs/g3doc/inotify.md @@ -112,11 +112,11 @@ attempts to queue a new event, it is already holding `fs.Watches.mu`. If we used `Inotify.mu` to also protect the event queue, this would violate the above lock ordering. -[dirent]: https://github.com/google/gvisor/blob/master/+/master/pkg/sentry/fs/dirent.go -[event]: https://github.com/google/gvisor/blob/master/+/master/pkg/sentry/fs/inotify_event.go -[fd_table]: https://github.com/google/gvisor/blob/master/+/master/pkg/sentry/kernel/fd_table.go -[inode]: https://github.com/google/gvisor/blob/master/+/master/pkg/sentry/fs/inode.go -[inode_watches]: https://github.com/google/gvisor/blob/master/+/master/pkg/sentry/fs/inode_inotify.go -[inotify]: https://github.com/google/gvisor/blob/master/+/master/pkg/sentry/fs/inotify.go -[syscall_dir]: https://github.com/google/gvisor/blob/master/+/master/pkg/sentry/syscalls/linux/ -[watch]: https://github.com/google/gvisor/blob/master/+/master/pkg/sentry/fs/inotify_watch.go +[dirent]: https://github.com/google/gvisor/blob/master/pkg/sentry/fs/dirent.go +[event]: https://github.com/google/gvisor/blob/master/pkg/sentry/fs/inotify_event.go +[fd_table]: https://github.com/google/gvisor/blob/master/pkg/sentry/kernel/fd_table.go +[inode]: https://github.com/google/gvisor/blob/master/pkg/sentry/fs/inode.go +[inode_watches]: https://github.com/google/gvisor/blob/master/pkg/sentry/fs/inode_inotify.go +[inotify]: https://github.com/google/gvisor/blob/master/pkg/sentry/fs/inotify.go +[syscall_dir]: https://github.com/google/gvisor/blob/master/pkg/sentry/syscalls/linux/ +[watch]: https://github.com/google/gvisor/blob/master/pkg/sentry/fs/inotify_watch.go diff --git a/pkg/sentry/fs/gofer/BUILD b/pkg/sentry/fs/gofer/BUILD index 971d3718e..fea135eea 100644 --- a/pkg/sentry/fs/gofer/BUILD +++ b/pkg/sentry/fs/gofer/BUILD @@ -9,6 +9,7 @@ go_library( "cache_policy.go", "context_file.go", "device.go", + "fifo.go", "file.go", "file_state.go", "fs.go", @@ -38,6 +39,7 @@ go_library( "//pkg/sentry/fs/fsutil", "//pkg/sentry/fs/host", "//pkg/sentry/kernel/auth", + "//pkg/sentry/kernel/pipe", "//pkg/sentry/kernel/time", "//pkg/sentry/memmap", "//pkg/sentry/socket/unix/transport", diff --git a/pkg/sentry/fs/gofer/attr.go b/pkg/sentry/fs/gofer/attr.go index 71cccdc34..6db4b762d 100644 --- a/pkg/sentry/fs/gofer/attr.go +++ b/pkg/sentry/fs/gofer/attr.go @@ -88,8 +88,9 @@ func bsize(pattr p9.Attr) int64 { if pattr.BlockSize > 0 { return int64(pattr.BlockSize) } - // Some files may have no clue of their block size. Better not to report - // something misleading or buggy and have a safe default. + // Some files, particularly those that are not on a local file system, + // may have no clue of their block size. Better not to report something + // misleading or buggy and have a safe default. return usermem.PageSize } @@ -149,6 +150,7 @@ func links(valid p9.AttrMask, pattr p9.Attr) uint64 { } // This node is likely backed by a file system that doesn't support links. + // // We could readdir() and count children directories to provide an accurate // link count. However this may be expensive since the gofer may be backed by remote // storage. Instead, simply return 2 links for directories and 1 for everything else diff --git a/pkg/sentry/fs/gofer/cache_policy.go b/pkg/sentry/fs/gofer/cache_policy.go index ebea03c42..07a564e92 100644 --- a/pkg/sentry/fs/gofer/cache_policy.go +++ b/pkg/sentry/fs/gofer/cache_policy.go @@ -127,6 +127,9 @@ func (cp cachePolicy) revalidate(ctx context.Context, name string, parent, child childIops, ok := child.InodeOperations.(*inodeOperations) if !ok { + if _, ok := child.InodeOperations.(*fifo); ok { + return false + } panic(fmt.Sprintf("revalidating inode operations of unknown type %T", child.InodeOperations)) } parentIops, ok := parent.InodeOperations.(*inodeOperations) diff --git a/pkg/sentry/fs/gofer/context_file.go b/pkg/sentry/fs/gofer/context_file.go index 3da818aed..125907d70 100644 --- a/pkg/sentry/fs/gofer/context_file.go +++ b/pkg/sentry/fs/gofer/context_file.go @@ -73,6 +73,20 @@ func (c *contextFile) setXattr(ctx context.Context, name, value string, flags ui return err } +func (c *contextFile) listXattr(ctx context.Context, size uint64) (map[string]struct{}, error) { + ctx.UninterruptibleSleepStart(false) + xattrs, err := c.file.ListXattr(size) + ctx.UninterruptibleSleepFinish(false) + return xattrs, err +} + +func (c *contextFile) removeXattr(ctx context.Context, name string) error { + ctx.UninterruptibleSleepStart(false) + err := c.file.RemoveXattr(name) + ctx.UninterruptibleSleepFinish(false) + return err +} + func (c *contextFile) allocate(ctx context.Context, mode p9.AllocateMode, offset, length uint64) error { ctx.UninterruptibleSleepStart(false) err := c.file.Allocate(mode, offset, length) diff --git a/pkg/sentry/fs/gofer/fifo.go b/pkg/sentry/fs/gofer/fifo.go new file mode 100644 index 000000000..456557058 --- /dev/null +++ b/pkg/sentry/fs/gofer/fifo.go @@ -0,0 +1,40 @@ +// 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 gofer + +import ( + "gvisor.dev/gvisor/pkg/context" + "gvisor.dev/gvisor/pkg/sentry/fs" +) + +// +stateify savable +type fifo struct { + fs.InodeOperations + fileIops *inodeOperations +} + +var _ fs.InodeOperations = (*fifo)(nil) + +// Rename implements fs.InodeOperations. It forwards the call to the underlying +// file inode to handle the file rename. Note that file key remains the same +// after the rename to keep the endpoint mapping. +func (i *fifo) Rename(ctx context.Context, inode *fs.Inode, oldParent *fs.Inode, oldName string, newParent *fs.Inode, newName string, replacement bool) error { + return i.fileIops.Rename(ctx, inode, oldParent, oldName, newParent, newName, replacement) +} + +// StatFS implements fs.InodeOperations. +func (i *fifo) StatFS(ctx context.Context) (fs.Info, error) { + return i.fileIops.StatFS(ctx) +} diff --git a/pkg/sentry/fs/gofer/gofer_test.go b/pkg/sentry/fs/gofer/gofer_test.go index 0c2f89ae8..2df2fe889 100644 --- a/pkg/sentry/fs/gofer/gofer_test.go +++ b/pkg/sentry/fs/gofer/gofer_test.go @@ -61,7 +61,7 @@ func rootTest(t *testing.T, name string, cp cachePolicy, fn func(context.Context ctx := contexttest.Context(t) sattr, rootInodeOperations := newInodeOperations(ctx, s, contextFile{ file: rootFile, - }, root.QID, p9.AttrMaskAll(), root.Attr, false /* socket */) + }, root.QID, p9.AttrMaskAll(), root.Attr) m := fs.NewMountSource(ctx, s, &filesystem{}, fs.MountSourceFlags{}) rootInode := fs.NewInode(ctx, rootInodeOperations, m, sattr) diff --git a/pkg/sentry/fs/gofer/inode.go b/pkg/sentry/fs/gofer/inode.go index ac28174d2..1c934981b 100644 --- a/pkg/sentry/fs/gofer/inode.go +++ b/pkg/sentry/fs/gofer/inode.go @@ -604,18 +604,23 @@ func (i *inodeOperations) Truncate(ctx context.Context, inode *fs.Inode, length } // GetXattr implements fs.InodeOperations.GetXattr. -func (i *inodeOperations) GetXattr(ctx context.Context, inode *fs.Inode, name string, size uint64) (string, error) { +func (i *inodeOperations) GetXattr(ctx context.Context, _ *fs.Inode, name string, size uint64) (string, error) { return i.fileState.file.getXattr(ctx, name, size) } // SetXattr implements fs.InodeOperations.SetXattr. -func (i *inodeOperations) SetXattr(ctx context.Context, inode *fs.Inode, name string, value string, flags uint32) error { +func (i *inodeOperations) SetXattr(ctx context.Context, _ *fs.Inode, name string, value string, flags uint32) error { return i.fileState.file.setXattr(ctx, name, value, flags) } // ListXattr implements fs.InodeOperations.ListXattr. -func (i *inodeOperations) ListXattr(context.Context, *fs.Inode) (map[string]struct{}, error) { - return nil, syscall.EOPNOTSUPP +func (i *inodeOperations) ListXattr(ctx context.Context, _ *fs.Inode, size uint64) (map[string]struct{}, error) { + return i.fileState.file.listXattr(ctx, size) +} + +// RemoveXattr implements fs.InodeOperations.RemoveXattr. +func (i *inodeOperations) RemoveXattr(ctx context.Context, _ *fs.Inode, name string) error { + return i.fileState.file.removeXattr(ctx, name) } // Allocate implements fs.InodeOperations.Allocate. diff --git a/pkg/sentry/fs/gofer/path.go b/pkg/sentry/fs/gofer/path.go index 0c1be05ef..a35c3a23d 100644 --- a/pkg/sentry/fs/gofer/path.go +++ b/pkg/sentry/fs/gofer/path.go @@ -23,14 +23,24 @@ import ( "gvisor.dev/gvisor/pkg/p9" "gvisor.dev/gvisor/pkg/sentry/device" "gvisor.dev/gvisor/pkg/sentry/fs" + "gvisor.dev/gvisor/pkg/sentry/kernel/pipe" "gvisor.dev/gvisor/pkg/sentry/socket/unix/transport" "gvisor.dev/gvisor/pkg/syserror" + "gvisor.dev/gvisor/pkg/usermem" ) // maxFilenameLen is the maximum length of a filename. This is dictated by 9P's // encoding of strings, which uses 2 bytes for the length prefix. const maxFilenameLen = (1 << 16) - 1 +func changeType(mode p9.FileMode, newType p9.FileMode) p9.FileMode { + if newType&^p9.FileModeMask != 0 { + panic(fmt.Sprintf("newType contained more bits than just file mode: %x", newType)) + } + clear := mode &^ p9.FileModeMask + return clear | newType +} + // Lookup loads an Inode at name into a Dirent based on the session's cache // policy. func (i *inodeOperations) Lookup(ctx context.Context, dir *fs.Inode, name string) (*fs.Dirent, error) { @@ -69,8 +79,25 @@ func (i *inodeOperations) Lookup(ctx context.Context, dir *fs.Inode, name string return nil, err } + if i.session().overrides != nil { + // Check if file belongs to a internal named pipe. Note that it doesn't need + // to check for sockets because it's done in newInodeOperations below. + deviceKey := device.MultiDeviceKey{ + Device: p9attr.RDev, + SecondaryDevice: i.session().connID, + Inode: qids[0].Path, + } + unlock := i.session().overrides.lock() + if pipeInode := i.session().overrides.getPipe(deviceKey); pipeInode != nil { + unlock() + pipeInode.IncRef() + return fs.NewDirent(ctx, pipeInode, name), nil + } + unlock() + } + // Construct the Inode operations. - sattr, node := newInodeOperations(ctx, i.fileState.s, newFile, qids[0], mask, p9attr, false) + sattr, node := newInodeOperations(ctx, i.fileState.s, newFile, qids[0], mask, p9attr) // Construct a positive Dirent. return fs.NewDirent(ctx, fs.NewInode(ctx, node, dir.MountSource, sattr), name), nil @@ -138,7 +165,7 @@ func (i *inodeOperations) Create(ctx context.Context, dir *fs.Inode, name string qid := qids[0] // Construct the InodeOperations. - sattr, iops := newInodeOperations(ctx, i.fileState.s, unopened, qid, mask, p9attr, false) + sattr, iops := newInodeOperations(ctx, i.fileState.s, unopened, qid, mask, p9attr) // Construct the positive Dirent. d := fs.NewDirent(ctx, fs.NewInode(ctx, iops, dir.MountSource, sattr), name) @@ -223,82 +250,115 @@ func (i *inodeOperations) Bind(ctx context.Context, dir *fs.Inode, name string, return nil, syserror.ENAMETOOLONG } - if i.session().endpoints == nil { + if i.session().overrides == nil { return nil, syscall.EOPNOTSUPP } - // Create replaces the directory fid with the newly created/opened - // file, so clone this directory so it doesn't change out from under - // this node. - _, newFile, err := i.fileState.file.walk(ctx, nil) + // Stabilize the override map while creation is in progress. + unlock := i.session().overrides.lock() + defer unlock() + + sattr, iops, err := i.createEndpointFile(ctx, dir, name, perm, p9.ModeSocket) if err != nil { return nil, err } - // We're not going to use newFile after return. - defer newFile.close(ctx) - // Stabilize the endpoint map while creation is in progress. - unlock := i.session().endpoints.lock() - defer unlock() + // Construct the positive Dirent. + childDir := fs.NewDirent(ctx, fs.NewInode(ctx, iops, dir.MountSource, sattr), name) + i.session().overrides.addBoundEndpoint(iops.fileState.key, childDir, ep) + return childDir, nil +} - // Create a regular file in the gofer and then mark it as a socket by - // adding this inode key in the 'endpoints' map. - owner := fs.FileOwnerFromContext(ctx) - hostFile, err := newFile.create(ctx, name, p9.ReadWrite, p9.FileMode(perm.LinuxMode()), p9.UID(owner.UID), p9.GID(owner.GID)) - if err != nil { - return nil, err +// CreateFifo implements fs.InodeOperations.CreateFifo. +func (i *inodeOperations) CreateFifo(ctx context.Context, dir *fs.Inode, name string, perm fs.FilePermissions) error { + if len(name) > maxFilenameLen { + return syserror.ENAMETOOLONG } - // We're not going to use this file. - hostFile.Close() - i.touchModificationAndStatusChangeTime(ctx, dir) + owner := fs.FileOwnerFromContext(ctx) + mode := p9.FileMode(perm.LinuxMode()) | p9.ModeNamedPipe - // Get the attributes of the file to create inode key. - qid, mask, attr, err := getattr(ctx, newFile) - if err != nil { - return nil, err + // N.B. FIFOs use major/minor numbers 0. + if _, err := i.fileState.file.mknod(ctx, name, mode, 0, 0, p9.UID(owner.UID), p9.GID(owner.GID)); err != nil { + if i.session().overrides == nil || err != syscall.EPERM { + return err + } + // If gofer doesn't support mknod, check if we can create an internal fifo. + return i.createInternalFifo(ctx, dir, name, owner, perm) } - key := device.MultiDeviceKey{ - Device: attr.RDev, - SecondaryDevice: i.session().connID, - Inode: qid.Path, + i.touchModificationAndStatusChangeTime(ctx, dir) + return nil +} + +func (i *inodeOperations) createInternalFifo(ctx context.Context, dir *fs.Inode, name string, owner fs.FileOwner, perm fs.FilePermissions) error { + if i.session().overrides == nil { + return syserror.EPERM } - // Create child dirent. + // Stabilize the override map while creation is in progress. + unlock := i.session().overrides.lock() + defer unlock() - // Get an unopened p9.File for the file we created so that it can be - // cloned and re-opened multiple times after creation. - _, unopened, err := i.fileState.file.walk(ctx, []string{name}) + sattr, fileOps, err := i.createEndpointFile(ctx, dir, name, perm, p9.ModeNamedPipe) if err != nil { - return nil, err + return err } - // Construct the InodeOperations. - sattr, iops := newInodeOperations(ctx, i.fileState.s, unopened, qid, mask, attr, true) + // First create a pipe. + p := pipe.NewPipe(true /* isNamed */, pipe.DefaultPipeSize, usermem.PageSize) + + // Wrap the fileOps with our Fifo. + iops := &fifo{ + InodeOperations: pipe.NewInodeOperations(ctx, perm, p), + fileIops: fileOps, + } + inode := fs.NewInode(ctx, iops, dir.MountSource, sattr) // Construct the positive Dirent. childDir := fs.NewDirent(ctx, fs.NewInode(ctx, iops, dir.MountSource, sattr), name) - i.session().endpoints.add(key, childDir, ep) - return childDir, nil + i.session().overrides.addPipe(fileOps.fileState.key, childDir, inode) + return nil } -// CreateFifo implements fs.InodeOperations.CreateFifo. -func (i *inodeOperations) CreateFifo(ctx context.Context, dir *fs.Inode, name string, perm fs.FilePermissions) error { - if len(name) > maxFilenameLen { - return syserror.ENAMETOOLONG +// Caller must hold Session.endpoint lock. +func (i *inodeOperations) createEndpointFile(ctx context.Context, dir *fs.Inode, name string, perm fs.FilePermissions, fileType p9.FileMode) (fs.StableAttr, *inodeOperations, error) { + _, dirClone, err := i.fileState.file.walk(ctx, nil) + if err != nil { + return fs.StableAttr{}, nil, err } + // We're not going to use dirClone after return. + defer dirClone.close(ctx) + // Create a regular file in the gofer and then mark it as a socket by + // adding this inode key in the 'overrides' map. owner := fs.FileOwnerFromContext(ctx) - mode := p9.FileMode(perm.LinuxMode()) | p9.ModeNamedPipe - - // N.B. FIFOs use major/minor numbers 0. - if _, err := i.fileState.file.mknod(ctx, name, mode, 0, 0, p9.UID(owner.UID), p9.GID(owner.GID)); err != nil { - return err + hostFile, err := dirClone.create(ctx, name, p9.ReadWrite, p9.FileMode(perm.LinuxMode()), p9.UID(owner.UID), p9.GID(owner.GID)) + if err != nil { + return fs.StableAttr{}, nil, err } + // We're not going to use this file. + hostFile.Close() i.touchModificationAndStatusChangeTime(ctx, dir) - return nil + + // Get the attributes of the file to create inode key. + qid, mask, attr, err := getattr(ctx, dirClone) + if err != nil { + return fs.StableAttr{}, nil, err + } + + // Get an unopened p9.File for the file we created so that it can be + // cloned and re-opened multiple times after creation. + _, unopened, err := i.fileState.file.walk(ctx, []string{name}) + if err != nil { + return fs.StableAttr{}, nil, err + } + + // Construct new inode with file type overridden. + attr.Mode = changeType(attr.Mode, fileType) + sattr, iops := newInodeOperations(ctx, i.fileState.s, unopened, qid, mask, attr) + return sattr, iops, nil } // Remove implements InodeOperations.Remove. @@ -307,20 +367,23 @@ func (i *inodeOperations) Remove(ctx context.Context, dir *fs.Inode, name string return syserror.ENAMETOOLONG } - var key device.MultiDeviceKey - removeSocket := false - if i.session().endpoints != nil { - // Find out if file being deleted is a socket that needs to be + var key *device.MultiDeviceKey + if i.session().overrides != nil { + // Find out if file being deleted is a socket or pipe that needs to be // removed from endpoint map. if d, err := i.Lookup(ctx, dir, name); err == nil { defer d.DecRef() - if fs.IsSocket(d.Inode.StableAttr) { - child := d.Inode.InodeOperations.(*inodeOperations) - key = child.fileState.key - removeSocket = true - // Stabilize the endpoint map while deletion is in progress. - unlock := i.session().endpoints.lock() + if fs.IsSocket(d.Inode.StableAttr) || fs.IsPipe(d.Inode.StableAttr) { + switch iops := d.Inode.InodeOperations.(type) { + case *inodeOperations: + key = &iops.fileState.key + case *fifo: + key = &iops.fileIops.fileState.key + } + + // Stabilize the override map while deletion is in progress. + unlock := i.session().overrides.lock() defer unlock() } } @@ -329,8 +392,8 @@ func (i *inodeOperations) Remove(ctx context.Context, dir *fs.Inode, name string if err := i.fileState.file.unlinkAt(ctx, name, 0); err != nil { return err } - if removeSocket { - i.session().endpoints.remove(key) + if key != nil { + i.session().overrides.remove(*key) } i.touchModificationAndStatusChangeTime(ctx, dir) diff --git a/pkg/sentry/fs/gofer/session.go b/pkg/sentry/fs/gofer/session.go index 498c4645a..f6b3ef178 100644 --- a/pkg/sentry/fs/gofer/session.go +++ b/pkg/sentry/fs/gofer/session.go @@ -33,60 +33,107 @@ import ( var DefaultDirentCacheSize uint64 = fs.DefaultDirentCacheSize // +stateify savable -type endpointMaps struct { - // mu protexts the direntMap, the keyMap, and the pathMap below. - mu sync.RWMutex `state:"nosave"` +type overrideInfo struct { + dirent *fs.Dirent + + // endpoint is set when dirent points to a socket. inode must not be set. + endpoint transport.BoundEndpoint + + // inode is set when dirent points to a pipe. endpoint must not be set. + inode *fs.Inode +} - // direntMap links sockets to their dirents. - // It is filled concurrently with the keyMap and is stored upon save. - // Before saving, this map is used to populate the pathMap. - direntMap map[transport.BoundEndpoint]*fs.Dirent +func (l *overrideInfo) inodeType() fs.InodeType { + switch { + case l.endpoint != nil: + return fs.Socket + case l.inode != nil: + return fs.Pipe + } + panic("endpoint or node must be set") +} - // keyMap links MultiDeviceKeys (containing inode IDs) to their sockets. +// +stateify savable +type overrideMaps struct { + // mu protexts the keyMap, and the pathMap below. + mu sync.RWMutex `state:"nosave"` + + // keyMap links MultiDeviceKeys (containing inode IDs) to their sockets/pipes. // It is not stored during save because the inode ID may change upon restore. - keyMap map[device.MultiDeviceKey]transport.BoundEndpoint `state:"nosave"` + keyMap map[device.MultiDeviceKey]*overrideInfo `state:"nosave"` - // pathMap links the sockets to their paths. + // pathMap links the sockets/pipes to their paths. // It is filled before saving from the direntMap and is stored upon save. // Upon restore, this map is used to re-populate the keyMap. - pathMap map[transport.BoundEndpoint]string + pathMap map[*overrideInfo]string +} + +// addBoundEndpoint adds the bound endpoint to the map. +// A reference is taken on the dirent argument. +// +// Precondition: maps must have been locked with 'lock'. +func (e *overrideMaps) addBoundEndpoint(key device.MultiDeviceKey, d *fs.Dirent, ep transport.BoundEndpoint) { + d.IncRef() + e.keyMap[key] = &overrideInfo{dirent: d, endpoint: ep} } -// add adds the endpoint to the maps. +// addPipe adds the pipe inode to the map. // A reference is taken on the dirent argument. // // Precondition: maps must have been locked with 'lock'. -func (e *endpointMaps) add(key device.MultiDeviceKey, d *fs.Dirent, ep transport.BoundEndpoint) { - e.keyMap[key] = ep +func (e *overrideMaps) addPipe(key device.MultiDeviceKey, d *fs.Dirent, inode *fs.Inode) { d.IncRef() - e.direntMap[ep] = d + e.keyMap[key] = &overrideInfo{dirent: d, inode: inode} } // remove deletes the key from the maps. // // Precondition: maps must have been locked with 'lock'. -func (e *endpointMaps) remove(key device.MultiDeviceKey) { - endpoint := e.get(key) +func (e *overrideMaps) remove(key device.MultiDeviceKey) { + endpoint := e.keyMap[key] delete(e.keyMap, key) - - d := e.direntMap[endpoint] - d.DecRef() - delete(e.direntMap, endpoint) + endpoint.dirent.DecRef() } // lock blocks other addition and removal operations from happening while // the backing file is being created or deleted. Returns a function that unlocks // the endpoint map. -func (e *endpointMaps) lock() func() { +func (e *overrideMaps) lock() func() { e.mu.Lock() return func() { e.mu.Unlock() } } -// get returns the endpoint mapped to the given key. +// getBoundEndpoint returns the bound endpoint mapped to the given key. // -// Precondition: maps must have been locked for reading. -func (e *endpointMaps) get(key device.MultiDeviceKey) transport.BoundEndpoint { - return e.keyMap[key] +// Precondition: maps must have been locked. +func (e *overrideMaps) getBoundEndpoint(key device.MultiDeviceKey) transport.BoundEndpoint { + if v := e.keyMap[key]; v != nil { + return v.endpoint + } + return nil +} + +// getPipe returns the pipe inode mapped to the given key. +// +// Precondition: maps must have been locked. +func (e *overrideMaps) getPipe(key device.MultiDeviceKey) *fs.Inode { + if v := e.keyMap[key]; v != nil { + return v.inode + } + return nil +} + +// getType returns the inode type if there is a corresponding endpoint for the +// given key. Returns false otherwise. +func (e *overrideMaps) getType(key device.MultiDeviceKey) (fs.InodeType, bool) { + e.mu.Lock() + v := e.keyMap[key] + e.mu.Unlock() + + if v != nil { + return v.inodeType(), true + } + return 0, false } // session holds state for each 9p session established during sys_mount. @@ -137,16 +184,16 @@ type session struct { // mounter is the EUID/EGID that mounted this file system. mounter fs.FileOwner `state:"wait"` - // endpoints is used to map inodes that represent socket files to their - // corresponding endpoint. Socket files are created as regular files in the - // gofer and their presence in this map indicate that they should indeed be - // socket files. This allows unix domain sockets to be used with paths that - // belong to a gofer. + // overrides is used to map inodes that represent socket/pipes files to their + // corresponding endpoint/iops. These files are created as regular files in + // the gofer and their presence in this map indicate that they should indeed + // be socket/pipe files. This allows unix domain sockets and named pipes to + // be used with paths that belong to a gofer. // // TODO(gvisor.dev/issue/1200): there are few possible races with someone // stat'ing the file and another deleting it concurrently, where the file // will not be reported as socket file. - endpoints *endpointMaps `state:"wait"` + overrides *overrideMaps `state:"wait"` } // Destroy tears down the session. @@ -179,15 +226,21 @@ func (s *session) SaveInodeMapping(inode *fs.Inode, path string) { // This is very unintuitive. We *CANNOT* trust the inode's StableAttrs, // because overlay copyUp may have changed them out from under us. // So much for "immutable". - sattr := inode.InodeOperations.(*inodeOperations).fileState.sattr - s.inodeMappings[sattr.InodeID] = path + switch iops := inode.InodeOperations.(type) { + case *inodeOperations: + s.inodeMappings[iops.fileState.sattr.InodeID] = path + case *fifo: + s.inodeMappings[iops.fileIops.fileState.sattr.InodeID] = path + default: + panic(fmt.Sprintf("Invalid type: %T", iops)) + } } -// newInodeOperations creates a new 9p fs.InodeOperations backed by a p9.File and attributes -// (p9.QID, p9.AttrMask, p9.Attr). +// newInodeOperations creates a new 9p fs.InodeOperations backed by a p9.File +// and attributes (p9.QID, p9.AttrMask, p9.Attr). // // Endpoints lock must not be held if socket == false. -func newInodeOperations(ctx context.Context, s *session, file contextFile, qid p9.QID, valid p9.AttrMask, attr p9.Attr, socket bool) (fs.StableAttr, *inodeOperations) { +func newInodeOperations(ctx context.Context, s *session, file contextFile, qid p9.QID, valid p9.AttrMask, attr p9.Attr) (fs.StableAttr, *inodeOperations) { deviceKey := device.MultiDeviceKey{ Device: attr.RDev, SecondaryDevice: s.connID, @@ -201,17 +254,11 @@ func newInodeOperations(ctx context.Context, s *session, file contextFile, qid p BlockSize: bsize(attr), } - if s.endpoints != nil { - if socket { - sattr.Type = fs.Socket - } else { - // If unix sockets are allowed on this filesystem, check if this file is - // supposed to be a socket file. - unlock := s.endpoints.lock() - if s.endpoints.get(deviceKey) != nil { - sattr.Type = fs.Socket - } - unlock() + if s.overrides != nil && sattr.Type == fs.RegularFile { + // If overrides are allowed on this filesystem, check if this file is + // supposed to be of a different type, e.g. socket. + if t, ok := s.overrides.getType(deviceKey); ok { + sattr.Type = t } } @@ -267,7 +314,7 @@ func Root(ctx context.Context, dev string, filesystem fs.Filesystem, superBlockF s.EnableLeakCheck("gofer.session") if o.privateunixsocket { - s.endpoints = newEndpointMaps() + s.overrides = newOverrideMaps() } // Construct the MountSource with the session and superBlockFlags. @@ -305,26 +352,24 @@ func Root(ctx context.Context, dev string, filesystem fs.Filesystem, superBlockF return nil, err } - sattr, iops := newInodeOperations(ctx, &s, s.attach, qid, valid, attr, false) + sattr, iops := newInodeOperations(ctx, &s, s.attach, qid, valid, attr) return fs.NewInode(ctx, iops, m, sattr), nil } -// newEndpointMaps creates a new endpointMaps. -func newEndpointMaps() *endpointMaps { - return &endpointMaps{ - direntMap: make(map[transport.BoundEndpoint]*fs.Dirent), - keyMap: make(map[device.MultiDeviceKey]transport.BoundEndpoint), - pathMap: make(map[transport.BoundEndpoint]string), +// newOverrideMaps creates a new overrideMaps. +func newOverrideMaps() *overrideMaps { + return &overrideMaps{ + keyMap: make(map[device.MultiDeviceKey]*overrideInfo), + pathMap: make(map[*overrideInfo]string), } } -// fillKeyMap populates key and dirent maps upon restore from saved -// pathmap. +// fillKeyMap populates key and dirent maps upon restore from saved pathmap. func (s *session) fillKeyMap(ctx context.Context) error { - unlock := s.endpoints.lock() + unlock := s.overrides.lock() defer unlock() - for ep, dirPath := range s.endpoints.pathMap { + for ep, dirPath := range s.overrides.pathMap { _, file, err := s.attach.walk(ctx, splitAbsolutePath(dirPath)) if err != nil { return fmt.Errorf("error filling endpointmaps, failed to walk to %q: %v", dirPath, err) @@ -341,25 +386,25 @@ func (s *session) fillKeyMap(ctx context.Context) error { Inode: qid.Path, } - s.endpoints.keyMap[key] = ep + s.overrides.keyMap[key] = ep } return nil } -// fillPathMap populates paths for endpoints from dirents in direntMap +// fillPathMap populates paths for overrides from dirents in direntMap // before save. func (s *session) fillPathMap() error { - unlock := s.endpoints.lock() + unlock := s.overrides.lock() defer unlock() - for ep, dir := range s.endpoints.direntMap { - mountRoot := dir.MountRoot() + for _, endpoint := range s.overrides.keyMap { + mountRoot := endpoint.dirent.MountRoot() defer mountRoot.DecRef() - dirPath, _ := dir.FullName(mountRoot) + dirPath, _ := endpoint.dirent.FullName(mountRoot) if dirPath == "" { return fmt.Errorf("error getting path from dirent") } - s.endpoints.pathMap[ep] = dirPath + s.overrides.pathMap[endpoint] = dirPath } return nil } @@ -368,7 +413,7 @@ func (s *session) fillPathMap() error { func (s *session) restoreEndpointMaps(ctx context.Context) error { // When restoring, only need to create the keyMap because the dirent and path // maps got stored through the save. - s.endpoints.keyMap = make(map[device.MultiDeviceKey]transport.BoundEndpoint) + s.overrides.keyMap = make(map[device.MultiDeviceKey]*overrideInfo) if err := s.fillKeyMap(ctx); err != nil { return fmt.Errorf("failed to insert sockets into endpoint map: %v", err) } @@ -376,6 +421,6 @@ func (s *session) restoreEndpointMaps(ctx context.Context) error { // Re-create pathMap because it can no longer be trusted as socket paths can // change while process continues to run. Empty pathMap will be re-filled upon // next save. - s.endpoints.pathMap = make(map[transport.BoundEndpoint]string) + s.overrides.pathMap = make(map[*overrideInfo]string) return nil } diff --git a/pkg/sentry/fs/gofer/session_state.go b/pkg/sentry/fs/gofer/session_state.go index 0285c5361..111da59f9 100644 --- a/pkg/sentry/fs/gofer/session_state.go +++ b/pkg/sentry/fs/gofer/session_state.go @@ -25,9 +25,9 @@ import ( // beforeSave is invoked by stateify. func (s *session) beforeSave() { - if s.endpoints != nil { + if s.overrides != nil { if err := s.fillPathMap(); err != nil { - panic("failed to save paths to endpoint map before saving" + err.Error()) + panic("failed to save paths to override map before saving" + err.Error()) } } } @@ -74,10 +74,10 @@ func (s *session) afterLoad() { panic(fmt.Sprintf("new attach name %v, want %v", opts.aname, s.aname)) } - // Check if endpointMaps exist when uds sockets are enabled - // (only pathmap will actualy have been saved). - if opts.privateunixsocket != (s.endpoints != nil) { - panic(fmt.Sprintf("new privateunixsocket option %v, want %v", opts.privateunixsocket, s.endpoints != nil)) + // Check if overrideMaps exist when uds sockets are enabled (only pathmaps + // will actually have been saved). + if opts.privateunixsocket != (s.overrides != nil) { + panic(fmt.Sprintf("new privateunixsocket option %v, want %v", opts.privateunixsocket, s.overrides != nil)) } if args.Flags != s.superBlockFlags { panic(fmt.Sprintf("new mount flags %v, want %v", args.Flags, s.superBlockFlags)) diff --git a/pkg/sentry/fs/gofer/socket.go b/pkg/sentry/fs/gofer/socket.go index 376cfce2c..10ba2f5f0 100644 --- a/pkg/sentry/fs/gofer/socket.go +++ b/pkg/sentry/fs/gofer/socket.go @@ -32,15 +32,15 @@ func (i *inodeOperations) BoundEndpoint(inode *fs.Inode, path string) transport. return nil } - if i.session().endpoints != nil { - unlock := i.session().endpoints.lock() + if i.session().overrides != nil { + unlock := i.session().overrides.lock() defer unlock() - ep := i.session().endpoints.get(i.fileState.key) + ep := i.session().overrides.getBoundEndpoint(i.fileState.key) if ep != nil { return ep } - // Not found in endpoints map, it may be a gofer backed unix socket... + // Not found in overrides map, it may be a gofer backed unix socket... } inode.IncRef() diff --git a/pkg/sentry/fs/host/util.go b/pkg/sentry/fs/host/util.go index e37e687c6..7c60dc1db 100644 --- a/pkg/sentry/fs/host/util.go +++ b/pkg/sentry/fs/host/util.go @@ -24,7 +24,7 @@ import ( "gvisor.dev/gvisor/pkg/sentry/device" "gvisor.dev/gvisor/pkg/sentry/fs" "gvisor.dev/gvisor/pkg/sentry/kernel/auth" - ktime "gvisor.dev/gvisor/pkg/sentry/kernel/time" + "gvisor.dev/gvisor/pkg/sentry/kernel/time" "gvisor.dev/gvisor/pkg/syserror" ) @@ -152,9 +152,9 @@ func unstableAttr(mo *superOperations, s *syscall.Stat_t) fs.UnstableAttr { Usage: s.Blocks * 512, Perms: fs.FilePermsFromMode(linux.FileMode(s.Mode)), Owner: owner(mo, s), - AccessTime: ktime.FromUnix(s.Atim.Sec, s.Atim.Nsec), - ModificationTime: ktime.FromUnix(s.Mtim.Sec, s.Mtim.Nsec), - StatusChangeTime: ktime.FromUnix(s.Ctim.Sec, s.Ctim.Nsec), + AccessTime: time.FromUnix(s.Atim.Sec, s.Atim.Nsec), + ModificationTime: time.FromUnix(s.Mtim.Sec, s.Mtim.Nsec), + StatusChangeTime: time.FromUnix(s.Ctim.Sec, s.Ctim.Nsec), Links: uint64(s.Nlink), } } @@ -165,6 +165,8 @@ type dirInfo struct { bufp int // location of next record in buf. } +// LINT.IfChange + // isBlockError unwraps os errors and checks if they are caused by EAGAIN or // EWOULDBLOCK. This is so they can be transformed into syserror.ErrWouldBlock. func isBlockError(err error) bool { @@ -177,6 +179,8 @@ func isBlockError(err error) bool { return false } +// LINT.ThenChange(../../fsimpl/host/util.go) + func hostEffectiveKIDs() (uint32, []uint32, error) { gids, err := os.Getgroups() if err != nil { diff --git a/pkg/sentry/fs/inode.go b/pkg/sentry/fs/inode.go index b66c091ab..55fb71c16 100644 --- a/pkg/sentry/fs/inode.go +++ b/pkg/sentry/fs/inode.go @@ -278,11 +278,19 @@ func (i *Inode) SetXattr(ctx context.Context, d *Dirent, name, value string, fla } // ListXattr calls i.InodeOperations.ListXattr with i as the Inode. -func (i *Inode) ListXattr(ctx context.Context) (map[string]struct{}, error) { +func (i *Inode) ListXattr(ctx context.Context, size uint64) (map[string]struct{}, error) { if i.overlay != nil { - return overlayListXattr(ctx, i.overlay) + return overlayListXattr(ctx, i.overlay, size) } - return i.InodeOperations.ListXattr(ctx, i) + return i.InodeOperations.ListXattr(ctx, i, size) +} + +// RemoveXattr calls i.InodeOperations.RemoveXattr with i as the Inode. +func (i *Inode) RemoveXattr(ctx context.Context, d *Dirent, name string) error { + if i.overlay != nil { + return overlayRemoveXattr(ctx, i.overlay, d, name) + } + return i.InodeOperations.RemoveXattr(ctx, i, name) } // CheckPermission will check if the caller may access this file in the diff --git a/pkg/sentry/fs/inode_operations.go b/pkg/sentry/fs/inode_operations.go index 70f2eae96..2bbfb72ef 100644 --- a/pkg/sentry/fs/inode_operations.go +++ b/pkg/sentry/fs/inode_operations.go @@ -190,7 +190,18 @@ type InodeOperations interface { // ListXattr returns the set of all extended attributes names that // have values. Inodes that do not support extended attributes return // EOPNOTSUPP. - ListXattr(ctx context.Context, inode *Inode) (map[string]struct{}, error) + // + // If this is called through the listxattr(2) syscall, size indicates the + // size of the buffer that the application has allocated to hold the + // attribute list. If the list would be larger than size, implementations may + // return ERANGE to indicate that the buffer is too small, but they are also + // free to ignore the hint entirely. All size checking is done independently + // at the syscall layer. + ListXattr(ctx context.Context, inode *Inode, size uint64) (map[string]struct{}, error) + + // RemoveXattr removes an extended attribute specified by name. Inodes that + // do not support extended attributes return EOPNOTSUPP. + RemoveXattr(ctx context.Context, inode *Inode, name string) error // Check determines whether an Inode can be accessed with the // requested permission mask using the context (which gives access diff --git a/pkg/sentry/fs/inode_overlay.go b/pkg/sentry/fs/inode_overlay.go index 4729b4aac..5ada33a32 100644 --- a/pkg/sentry/fs/inode_overlay.go +++ b/pkg/sentry/fs/inode_overlay.go @@ -564,15 +564,15 @@ func overlaySetxattr(ctx context.Context, o *overlayEntry, d *Dirent, name, valu return o.upper.SetXattr(ctx, d, name, value, flags) } -func overlayListXattr(ctx context.Context, o *overlayEntry) (map[string]struct{}, error) { +func overlayListXattr(ctx context.Context, o *overlayEntry, size uint64) (map[string]struct{}, error) { o.copyMu.RLock() defer o.copyMu.RUnlock() var names map[string]struct{} var err error if o.upper != nil { - names, err = o.upper.ListXattr(ctx) + names, err = o.upper.ListXattr(ctx, size) } else { - names, err = o.lower.ListXattr(ctx) + names, err = o.lower.ListXattr(ctx, size) } for name := range names { // Same as overlayGetXattr, we shouldn't forward along @@ -584,6 +584,18 @@ func overlayListXattr(ctx context.Context, o *overlayEntry) (map[string]struct{} return names, err } +func overlayRemoveXattr(ctx context.Context, o *overlayEntry, d *Dirent, name string) error { + // Don't allow changes to overlay xattrs through a removexattr syscall. + if strings.HasPrefix(XattrOverlayPrefix, name) { + return syserror.EPERM + } + + if err := copyUp(ctx, d); err != nil { + return err + } + return o.upper.RemoveXattr(ctx, d, name) +} + func overlayCheck(ctx context.Context, o *overlayEntry, p PermMask) error { o.copyMu.RLock() // Hot path. Avoid defers. diff --git a/pkg/sentry/fs/inotify.go b/pkg/sentry/fs/inotify.go index 928c90aa0..e3a715c1f 100644 --- a/pkg/sentry/fs/inotify.go +++ b/pkg/sentry/fs/inotify.go @@ -143,7 +143,10 @@ func (i *Inotify) Read(ctx context.Context, _ *File, dst usermem.IOSequence, _ i } var writeLen int64 - for event := i.events.Front(); event != nil; event = event.Next() { + for it := i.events.Front(); it != nil; { + event := it + it = it.Next() + // Does the buffer have enough remaining space to hold the event we're // about to write out? if dst.NumBytes() < int64(event.sizeOf()) { diff --git a/pkg/sentry/fs/mount_test.go b/pkg/sentry/fs/mount_test.go index e672a438c..a3d10770b 100644 --- a/pkg/sentry/fs/mount_test.go +++ b/pkg/sentry/fs/mount_test.go @@ -36,11 +36,12 @@ func mountPathsAre(root *Dirent, got []*Mount, want ...string) error { gotPaths := make(map[string]struct{}, len(got)) gotStr := make([]string, len(got)) for i, g := range got { - groot := g.Root() - name, _ := groot.FullName(root) - groot.DecRef() - gotStr[i] = name - gotPaths[name] = struct{}{} + if groot := g.Root(); groot != nil { + name, _ := groot.FullName(root) + groot.DecRef() + gotStr[i] = name + gotPaths[name] = struct{}{} + } } if len(got) != len(want) { return fmt.Errorf("mount paths are different, got: %q, want: %q", gotStr, want) diff --git a/pkg/sentry/fs/mounts.go b/pkg/sentry/fs/mounts.go index 574a2cc91..c7981f66e 100644 --- a/pkg/sentry/fs/mounts.go +++ b/pkg/sentry/fs/mounts.go @@ -100,10 +100,14 @@ func newUndoMount(d *Dirent) *Mount { } } -// Root returns the root dirent of this mount. Callers must call DecRef on the -// returned dirent. +// Root returns the root dirent of this mount. +// +// This may return nil if the mount has already been free. Callers must handle this +// case appropriately. If non-nil, callers must call DecRef on the returned *Dirent. func (m *Mount) Root() *Dirent { - m.root.IncRef() + if !m.root.TryIncRef() { + return nil + } return m.root } diff --git a/pkg/sentry/fs/proc/BUILD b/pkg/sentry/fs/proc/BUILD index 280093c5e..77c2c5c0e 100644 --- a/pkg/sentry/fs/proc/BUILD +++ b/pkg/sentry/fs/proc/BUILD @@ -36,6 +36,7 @@ go_library( "//pkg/sentry/fs/proc/device", "//pkg/sentry/fs/proc/seqfile", "//pkg/sentry/fs/ramfs", + "//pkg/sentry/fsbridge", "//pkg/sentry/inet", "//pkg/sentry/kernel", "//pkg/sentry/kernel/auth", diff --git a/pkg/sentry/fs/proc/README.md b/pkg/sentry/fs/proc/README.md index 5d4ec6c7b..6667a0916 100644 --- a/pkg/sentry/fs/proc/README.md +++ b/pkg/sentry/fs/proc/README.md @@ -11,6 +11,8 @@ inconsistency, please file a bug. The following files are implemented: +<!-- mdformat off(don't wrap the table) --> + | File /proc/ | Content | | :------------------------ | :---------------------------------------------------- | | [cpuinfo](#cpuinfo) | Info about the CPU | @@ -22,6 +24,8 @@ The following files are implemented: | [uptime](#uptime) | Wall clock since boot, combined idle time of all cpus | | [version](#version) | Kernel version | +<!-- mdformat on --> + ### cpuinfo ```bash diff --git a/pkg/sentry/fs/proc/mounts.go b/pkg/sentry/fs/proc/mounts.go index c10888100..94deb553b 100644 --- a/pkg/sentry/fs/proc/mounts.go +++ b/pkg/sentry/fs/proc/mounts.go @@ -60,13 +60,15 @@ func forEachMount(t *kernel.Task, fn func(string, *fs.Mount)) { }) for _, m := range ms { mroot := m.Root() + if mroot == nil { + continue // No longer valid. + } mountPath, desc := mroot.FullName(rootDir) mroot.DecRef() if !desc { // MountSources that are not descendants of the chroot jail are ignored. continue } - fn(mountPath, m) } } @@ -91,6 +93,12 @@ func (mif *mountInfoFile) ReadSeqFileData(ctx context.Context, handle seqfile.Se var buf bytes.Buffer forEachMount(mif.t, func(mountPath string, m *fs.Mount) { + mroot := m.Root() + if mroot == nil { + return // No longer valid. + } + defer mroot.DecRef() + // Format: // 36 35 98:0 /mnt1 /mnt2 rw,noatime master:1 - ext3 /dev/root rw,errors=continue // (1)(2)(3) (4) (5) (6) (7) (8) (9) (10) (11) @@ -107,9 +115,6 @@ func (mif *mountInfoFile) ReadSeqFileData(ctx context.Context, handle seqfile.Se // (3) Major:Minor device ID. We don't have a superblock, so we // just use the root inode device number. - mroot := m.Root() - defer mroot.DecRef() - sa := mroot.Inode.StableAttr fmt.Fprintf(&buf, "%d:%d ", sa.DeviceFileMajor, sa.DeviceFileMinor) @@ -207,6 +212,9 @@ func (mf *mountsFile) ReadSeqFileData(ctx context.Context, handle seqfile.SeqHan // // The "needs dump"and fsck flags are always 0, which is allowed. root := m.Root() + if root == nil { + return // No longer valid. + } defer root.DecRef() flags := root.Inode.MountSource.Flags diff --git a/pkg/sentry/fs/proc/net.go b/pkg/sentry/fs/proc/net.go index 6f2775344..95d5817ff 100644 --- a/pkg/sentry/fs/proc/net.go +++ b/pkg/sentry/fs/proc/net.go @@ -43,7 +43,10 @@ import ( // newNet creates a new proc net entry. func (p *proc) newNetDir(ctx context.Context, k *kernel.Kernel, msrc *fs.MountSource) *fs.Inode { var contents map[string]*fs.Inode - if s := p.k.NetworkStack(); s != nil { + // TODO(gvisor.dev/issue/1833): Support for using the network stack in the + // network namespace of the calling process. We should make this per-process, + // a.k.a. /proc/PID/net, and make /proc/net a symlink to /proc/self/net. + if s := p.k.RootNetworkNamespace().Stack(); s != nil { contents = map[string]*fs.Inode{ "dev": seqfile.NewSeqFileInode(ctx, &netDev{s: s}, msrc), "snmp": seqfile.NewSeqFileInode(ctx, &netSnmp{s: s}, msrc), diff --git a/pkg/sentry/fs/proc/sys_net.go b/pkg/sentry/fs/proc/sys_net.go index 0772d4ae4..d4c4b533d 100644 --- a/pkg/sentry/fs/proc/sys_net.go +++ b/pkg/sentry/fs/proc/sys_net.go @@ -357,7 +357,9 @@ func (p *proc) newSysNetIPv4Dir(ctx context.Context, msrc *fs.MountSource, s ine func (p *proc) newSysNetDir(ctx context.Context, msrc *fs.MountSource) *fs.Inode { var contents map[string]*fs.Inode - if s := p.k.NetworkStack(); s != nil { + // TODO(gvisor.dev/issue/1833): Support for using the network stack in the + // network namespace of the calling process. + if s := p.k.RootNetworkNamespace().Stack(); s != nil { contents = map[string]*fs.Inode{ "ipv4": p.newSysNetIPv4Dir(ctx, msrc, s), "core": p.newSysNetCore(ctx, msrc, s), diff --git a/pkg/sentry/fs/proc/task.go b/pkg/sentry/fs/proc/task.go index ca020e11e..4e9b0fc00 100644 --- a/pkg/sentry/fs/proc/task.go +++ b/pkg/sentry/fs/proc/task.go @@ -28,6 +28,7 @@ import ( "gvisor.dev/gvisor/pkg/sentry/fs/proc/device" "gvisor.dev/gvisor/pkg/sentry/fs/proc/seqfile" "gvisor.dev/gvisor/pkg/sentry/fs/ramfs" + "gvisor.dev/gvisor/pkg/sentry/fsbridge" "gvisor.dev/gvisor/pkg/sentry/kernel" "gvisor.dev/gvisor/pkg/sentry/limits" "gvisor.dev/gvisor/pkg/sentry/mm" @@ -71,24 +72,26 @@ var _ fs.InodeOperations = (*taskDir)(nil) // newTaskDir creates a new proc task entry. func (p *proc) newTaskDir(t *kernel.Task, msrc *fs.MountSource, isThreadGroup bool) *fs.Inode { contents := map[string]*fs.Inode{ - "auxv": newAuxvec(t, msrc), - "cmdline": newExecArgInode(t, msrc, cmdlineExecArg), - "comm": newComm(t, msrc), - "environ": newExecArgInode(t, msrc, environExecArg), - "exe": newExe(t, msrc), - "fd": newFdDir(t, msrc), - "fdinfo": newFdInfoDir(t, msrc), - "gid_map": newGIDMap(t, msrc), - "io": newIO(t, msrc, isThreadGroup), - "maps": newMaps(t, msrc), - "mountinfo": seqfile.NewSeqFileInode(t, &mountInfoFile{t: t}, msrc), - "mounts": seqfile.NewSeqFileInode(t, &mountsFile{t: t}, msrc), - "ns": newNamespaceDir(t, msrc), - "smaps": newSmaps(t, msrc), - "stat": newTaskStat(t, msrc, isThreadGroup, p.pidns), - "statm": newStatm(t, msrc), - "status": newStatus(t, msrc, p.pidns), - "uid_map": newUIDMap(t, msrc), + "auxv": newAuxvec(t, msrc), + "cmdline": newExecArgInode(t, msrc, cmdlineExecArg), + "comm": newComm(t, msrc), + "environ": newExecArgInode(t, msrc, environExecArg), + "exe": newExe(t, msrc), + "fd": newFdDir(t, msrc), + "fdinfo": newFdInfoDir(t, msrc), + "gid_map": newGIDMap(t, msrc), + "io": newIO(t, msrc, isThreadGroup), + "maps": newMaps(t, msrc), + "mountinfo": seqfile.NewSeqFileInode(t, &mountInfoFile{t: t}, msrc), + "mounts": seqfile.NewSeqFileInode(t, &mountsFile{t: t}, msrc), + "ns": newNamespaceDir(t, msrc), + "oom_score": newOOMScore(t, msrc), + "oom_score_adj": newOOMScoreAdj(t, msrc), + "smaps": newSmaps(t, msrc), + "stat": newTaskStat(t, msrc, isThreadGroup, p.pidns), + "statm": newStatm(t, msrc), + "status": newStatus(t, msrc, p.pidns), + "uid_map": newUIDMap(t, msrc), } if isThreadGroup { contents["task"] = p.newSubtasks(t, msrc) @@ -249,7 +252,7 @@ func newExe(t *kernel.Task, msrc *fs.MountSource) *fs.Inode { return newProcInode(t, exeSymlink, msrc, fs.Symlink, t) } -func (e *exe) executable() (d *fs.Dirent, err error) { +func (e *exe) executable() (file fsbridge.File, err error) { e.t.WithMuLocked(func(t *kernel.Task) { mm := t.MemoryManager() if mm == nil { @@ -262,8 +265,8 @@ func (e *exe) executable() (d *fs.Dirent, err error) { // The MemoryManager may be destroyed, in which case // MemoryManager.destroy will simply set the executable to nil // (with locks held). - d = mm.Executable() - if d == nil { + file = mm.Executable() + if file == nil { err = syserror.ENOENT } }) @@ -283,15 +286,7 @@ func (e *exe) Readlink(ctx context.Context, inode *fs.Inode) (string, error) { } defer exec.DecRef() - root := fs.RootFromContext(ctx) - if root == nil { - // This doesn't correspond to anything in Linux because the vfs is - // global there. - return "", syserror.EINVAL - } - defer root.DecRef() - n, _ := exec.FullName(root) - return n, nil + return exec.PathnameWithDeleted(ctx), nil } // namespaceSymlink represents a symlink in the namespacefs, such as the files @@ -803,4 +798,92 @@ func (f *auxvecFile) Read(ctx context.Context, _ *fs.File, dst usermem.IOSequenc return int64(n), err } +// newOOMScore returns a oom_score file. It is a stub that always returns 0. +// TODO(gvisor.dev/issue/1967) +func newOOMScore(t *kernel.Task, msrc *fs.MountSource) *fs.Inode { + return newStaticProcInode(t, msrc, []byte("0\n")) +} + +// oomScoreAdj is a file containing the oom_score adjustment for a task. +// +// +stateify savable +type oomScoreAdj struct { + fsutil.SimpleFileInode + + t *kernel.Task +} + +// +stateify savable +type oomScoreAdjFile struct { + fsutil.FileGenericSeek `state:"nosave"` + fsutil.FileNoIoctl `state:"nosave"` + fsutil.FileNoMMap `state:"nosave"` + fsutil.FileNoSplice `state:"nosave"` + fsutil.FileNoopFlush `state:"nosave"` + fsutil.FileNoopFsync `state:"nosave"` + fsutil.FileNoopRelease `state:"nosave"` + fsutil.FileNotDirReaddir `state:"nosave"` + fsutil.FileUseInodeUnstableAttr `state:"nosave"` + waiter.AlwaysReady `state:"nosave"` + + t *kernel.Task +} + +// newOOMScoreAdj returns a oom_score_adj file. +func newOOMScoreAdj(t *kernel.Task, msrc *fs.MountSource) *fs.Inode { + i := &oomScoreAdj{ + SimpleFileInode: *fsutil.NewSimpleFileInode(t, fs.RootOwner, fs.FilePermsFromMode(0644), linux.PROC_SUPER_MAGIC), + t: t, + } + return newProcInode(t, i, msrc, fs.SpecialFile, t) +} + +// Truncate implements fs.InodeOperations.Truncate. Truncate is called when +// O_TRUNC is specified for any kind of existing Dirent but is not called via +// (f)truncate for proc files. +func (*oomScoreAdj) Truncate(context.Context, *fs.Inode, int64) error { + return nil +} + +// GetFile implements fs.InodeOperations.GetFile. +func (o *oomScoreAdj) GetFile(ctx context.Context, dirent *fs.Dirent, flags fs.FileFlags) (*fs.File, error) { + return fs.NewFile(ctx, dirent, flags, &oomScoreAdjFile{t: o.t}), nil +} + +// Read implements fs.FileOperations.Read. +func (f *oomScoreAdjFile) Read(ctx context.Context, _ *fs.File, dst usermem.IOSequence, offset int64) (int64, error) { + if offset != 0 { + return 0, io.EOF + } + adj, err := f.t.OOMScoreAdj() + if err != nil { + return 0, err + } + adjBytes := []byte(strconv.FormatInt(int64(adj), 10) + "\n") + n, err := dst.CopyOut(ctx, adjBytes) + return int64(n), err +} + +// Write implements fs.FileOperations.Write. +func (f *oomScoreAdjFile) Write(ctx context.Context, _ *fs.File, src usermem.IOSequence, offset int64) (int64, error) { + if src.NumBytes() == 0 { + return 0, nil + } + + // Limit input size so as not to impact performance if input size is large. + src = src.TakeFirst(usermem.PageSize - 1) + + var v int32 + n, err := usermem.CopyInt32StringInVec(ctx, src.IO, src.Addrs, &v, src.Opts) + if err != nil { + return 0, err + } + + if err := f.t.SetOOMScoreAdj(v); err != nil { + return 0, err + } + + return n, nil +} + // LINT.ThenChange(../../fsimpl/proc/task.go|../../fsimpl/proc/task_files.go) diff --git a/pkg/sentry/fs/tmpfs/inode_file.go b/pkg/sentry/fs/tmpfs/inode_file.go index dabc10662..25abbc151 100644 --- a/pkg/sentry/fs/tmpfs/inode_file.go +++ b/pkg/sentry/fs/tmpfs/inode_file.go @@ -17,6 +17,7 @@ package tmpfs import ( "fmt" "io" + "math" "time" "gvisor.dev/gvisor/pkg/abi/linux" @@ -444,10 +445,15 @@ func (rw *fileReadWriter) WriteFromBlocks(srcs safemem.BlockSeq) (uint64, error) defer rw.f.dataMu.Unlock() // Compute the range to write. - end := fs.WriteEndOffset(rw.offset, int64(srcs.NumBytes())) - if end == rw.offset { // srcs.NumBytes() == 0? + if srcs.NumBytes() == 0 { + // Nothing to do. return 0, nil } + end := fs.WriteEndOffset(rw.offset, int64(srcs.NumBytes())) + if end == math.MaxInt64 { + // Overflow. + return 0, syserror.EINVAL + } // Check if seals prevent either file growth or all writes. switch { diff --git a/pkg/sentry/fs/tmpfs/tmpfs.go b/pkg/sentry/fs/tmpfs/tmpfs.go index c00cef0a5..3c2b583ae 100644 --- a/pkg/sentry/fs/tmpfs/tmpfs.go +++ b/pkg/sentry/fs/tmpfs/tmpfs.go @@ -159,8 +159,13 @@ func (d *Dir) SetXattr(ctx context.Context, i *fs.Inode, name, value string, fla } // ListXattr implements fs.InodeOperations.ListXattr. -func (d *Dir) ListXattr(ctx context.Context, i *fs.Inode) (map[string]struct{}, error) { - return d.ramfsDir.ListXattr(ctx, i) +func (d *Dir) ListXattr(ctx context.Context, i *fs.Inode, size uint64) (map[string]struct{}, error) { + return d.ramfsDir.ListXattr(ctx, i, size) +} + +// RemoveXattr implements fs.InodeOperations.RemoveXattr. +func (d *Dir) RemoveXattr(ctx context.Context, i *fs.Inode, name string) error { + return d.ramfsDir.RemoveXattr(ctx, i, name) } // Lookup implements fs.InodeOperations.Lookup. diff --git a/pkg/sentry/fs/tty/slave.go b/pkg/sentry/fs/tty/slave.go index db55cdc48..6a2dbc576 100644 --- a/pkg/sentry/fs/tty/slave.go +++ b/pkg/sentry/fs/tty/slave.go @@ -73,7 +73,7 @@ func (si *slaveInodeOperations) Release(ctx context.Context) { } // Truncate implements fs.InodeOperations.Truncate. -func (slaveInodeOperations) Truncate(context.Context, *fs.Inode, int64) error { +func (*slaveInodeOperations) Truncate(context.Context, *fs.Inode, int64) error { return nil } |