From 0e2f1b7abd219f39d67cc2cecd00c441a13eeb29 Mon Sep 17 00:00:00 2001 From: Adin Scannell Date: Mon, 27 Jan 2020 15:17:58 -0800 Subject: Update package locations. Because the abi will depend on the core types for marshalling (usermem, context, safemem, safecopy), these need to be flattened from the sentry directory. These packages contain no sentry-specific details. PiperOrigin-RevId: 291811289 --- pkg/sentry/fsimpl/kernfs/dynamic_bytes_file.go | 4 ++-- 1 file changed, 2 insertions(+), 2 deletions(-) (limited to 'pkg/sentry/fsimpl/kernfs/dynamic_bytes_file.go') diff --git a/pkg/sentry/fsimpl/kernfs/dynamic_bytes_file.go b/pkg/sentry/fsimpl/kernfs/dynamic_bytes_file.go index 75624e0b1..373f801ff 100644 --- a/pkg/sentry/fsimpl/kernfs/dynamic_bytes_file.go +++ b/pkg/sentry/fsimpl/kernfs/dynamic_bytes_file.go @@ -18,11 +18,11 @@ import ( "fmt" "gvisor.dev/gvisor/pkg/abi/linux" - "gvisor.dev/gvisor/pkg/sentry/context" + "gvisor.dev/gvisor/pkg/context" "gvisor.dev/gvisor/pkg/sentry/kernel/auth" - "gvisor.dev/gvisor/pkg/sentry/usermem" "gvisor.dev/gvisor/pkg/sentry/vfs" "gvisor.dev/gvisor/pkg/syserror" + "gvisor.dev/gvisor/pkg/usermem" ) // DynamicBytesFile implements kernfs.Inode and represents a read-only -- cgit v1.2.3 From 396c574db276ae1424af7098b5cd917e2bed9921 Mon Sep 17 00:00:00 2001 From: Fabricio Voznika Date: Tue, 28 Jan 2020 18:30:36 -0800 Subject: Add support for WritableSource in DynamicBytesFileDescriptionImpl WritableSource is a convenience interface used for files that can be written to, e.g. /proc/net/ipv4/tpc_sack. It reads max of 4KB and only from offset 0 which should cover most cases. It can be extended as neeed. Updates #1195 PiperOrigin-RevId: 292056924 --- pkg/sentry/fsimpl/kernfs/dynamic_bytes_file.go | 4 +- pkg/sentry/fsimpl/proc/tasks.go | 2 +- pkg/sentry/fsimpl/proc/tasks_sys.go | 84 +++++++++++-- pkg/sentry/vfs/file_description_impl_util.go | 76 +++++++++--- pkg/sentry/vfs/file_description_impl_util_test.go | 138 +++++++++++++++++----- 5 files changed, 250 insertions(+), 54 deletions(-) (limited to 'pkg/sentry/fsimpl/kernfs/dynamic_bytes_file.go') diff --git a/pkg/sentry/fsimpl/kernfs/dynamic_bytes_file.go b/pkg/sentry/fsimpl/kernfs/dynamic_bytes_file.go index 373f801ff..733792c78 100644 --- a/pkg/sentry/fsimpl/kernfs/dynamic_bytes_file.go +++ b/pkg/sentry/fsimpl/kernfs/dynamic_bytes_file.go @@ -108,12 +108,12 @@ func (fd *DynamicBytesFD) PRead(ctx context.Context, dst usermem.IOSequence, off // Write implements vfs.FileDescriptionImpl.Write. func (fd *DynamicBytesFD) Write(ctx context.Context, src usermem.IOSequence, opts vfs.WriteOptions) (int64, error) { - return fd.FileDescriptionDefaultImpl.Write(ctx, src, opts) + return fd.DynamicBytesFileDescriptionImpl.Write(ctx, src, opts) } // PWrite implements vfs.FileDescriptionImpl.PWrite. func (fd *DynamicBytesFD) PWrite(ctx context.Context, src usermem.IOSequence, offset int64, opts vfs.WriteOptions) (int64, error) { - return fd.FileDescriptionDefaultImpl.PWrite(ctx, src, offset, opts) + return fd.DynamicBytesFileDescriptionImpl.PWrite(ctx, src, offset, opts) } // Release implements vfs.FileDescriptionImpl.Release. diff --git a/pkg/sentry/fsimpl/proc/tasks.go b/pkg/sentry/fsimpl/proc/tasks.go index e0cb9c47b..14bd334e8 100644 --- a/pkg/sentry/fsimpl/proc/tasks.go +++ b/pkg/sentry/fsimpl/proc/tasks.go @@ -69,7 +69,7 @@ func newTasksInode(inoGen InoGenerator, k *kernel.Kernel, pidns *kernel.PIDNames "cpuinfo": newDentry(root, inoGen.NextIno(), 0444, newStaticFile(cpuInfoData(k))), //"filesystems": newDentry(root, inoGen.NextIno(), 0444, &filesystemsData{}), "loadavg": newDentry(root, inoGen.NextIno(), 0444, &loadavgData{}), - "sys": newSysDir(root, inoGen), + "sys": newSysDir(root, inoGen, k), "meminfo": newDentry(root, inoGen.NextIno(), 0444, &meminfoData{}), "mounts": kernfs.NewStaticSymlink(root, inoGen.NextIno(), "self/mounts"), "net": newNetDir(root, inoGen, k), diff --git a/pkg/sentry/fsimpl/proc/tasks_sys.go b/pkg/sentry/fsimpl/proc/tasks_sys.go index ad963870b..c7ce74883 100644 --- a/pkg/sentry/fsimpl/proc/tasks_sys.go +++ b/pkg/sentry/fsimpl/proc/tasks_sys.go @@ -21,12 +21,16 @@ import ( "gvisor.dev/gvisor/pkg/abi/linux" "gvisor.dev/gvisor/pkg/context" "gvisor.dev/gvisor/pkg/sentry/fsimpl/kernfs" + "gvisor.dev/gvisor/pkg/sentry/inet" "gvisor.dev/gvisor/pkg/sentry/kernel" "gvisor.dev/gvisor/pkg/sentry/kernel/auth" + "gvisor.dev/gvisor/pkg/sentry/vfs" + "gvisor.dev/gvisor/pkg/syserror" + "gvisor.dev/gvisor/pkg/usermem" ) // newSysDir returns the dentry corresponding to /proc/sys directory. -func newSysDir(root *auth.Credentials, inoGen InoGenerator) *kernfs.Dentry { +func newSysDir(root *auth.Credentials, inoGen InoGenerator, k *kernel.Kernel) *kernfs.Dentry { return kernfs.NewStaticDir(root, inoGen.NextIno(), 0555, map[string]*kernfs.Dentry{ "kernel": kernfs.NewStaticDir(root, inoGen.NextIno(), 0555, map[string]*kernfs.Dentry{ "hostname": newDentry(root, inoGen.NextIno(), 0444, &hostnameData{}), @@ -38,18 +42,18 @@ func newSysDir(root *auth.Credentials, inoGen InoGenerator) *kernfs.Dentry { "mmap_min_addr": newDentry(root, inoGen.NextIno(), 0444, &mmapMinAddrData{}), "overcommit_memory": newDentry(root, inoGen.NextIno(), 0444, newStaticFile("0\n")), }), - "net": newSysNetDir(root, inoGen), + "net": newSysNetDir(root, inoGen, k), }) } // newSysNetDir returns the dentry corresponding to /proc/sys/net directory. -func newSysNetDir(root *auth.Credentials, inoGen InoGenerator) *kernfs.Dentry { - return kernfs.NewStaticDir(root, inoGen.NextIno(), 0555, map[string]*kernfs.Dentry{ - "net": kernfs.NewStaticDir(root, inoGen.NextIno(), 0555, map[string]*kernfs.Dentry{ +func newSysNetDir(root *auth.Credentials, inoGen InoGenerator, k *kernel.Kernel) *kernfs.Dentry { + var contents map[string]*kernfs.Dentry + + if stack := k.NetworkStack(); stack != nil { + contents = map[string]*kernfs.Dentry{ "ipv4": kernfs.NewStaticDir(root, inoGen.NextIno(), 0555, map[string]*kernfs.Dentry{ - // Add tcp_sack. - // TODO(gvisor.dev/issue/1195): tcp_sack allows write(2) - // "tcp_sack": newTCPSackInode(ctx, msrc, s), + "tcp_sack": newDentry(root, inoGen.NextIno(), 0644, &tcpSackData{stack: stack}), // The following files are simple stubs until they are implemented in // netstack, most of these files are configuration related. We use the @@ -103,7 +107,11 @@ func newSysNetDir(root *auth.Credentials, inoGen InoGenerator) *kernfs.Dentry { "wmem_default": newDentry(root, inoGen.NextIno(), 0444, newStaticFile("212992")), "wmem_max": newDentry(root, inoGen.NextIno(), 0444, newStaticFile("212992")), }), - }), + } + } + + return kernfs.NewStaticDir(root, inoGen.NextIno(), 0555, map[string]*kernfs.Dentry{ + "net": kernfs.NewStaticDir(root, inoGen.NextIno(), 0555, contents), }) } @@ -141,3 +149,61 @@ func (*hostnameData) Generate(ctx context.Context, buf *bytes.Buffer) error { buf.WriteString("\n") return nil } + +// tcpSackData implements vfs.WritableDynamicBytesSource for +// /proc/sys/net/tcp_sack. +// +// +stateify savable +type tcpSackData struct { + kernfs.DynamicBytesFile + + stack inet.Stack `state:"wait"` + enabled *bool +} + +var _ vfs.WritableDynamicBytesSource = (*tcpSackData)(nil) + +// Generate implements vfs.DynamicBytesSource. +func (d *tcpSackData) Generate(ctx context.Context, buf *bytes.Buffer) error { + if d.enabled == nil { + sack, err := d.stack.TCPSACKEnabled() + if err != nil { + return err + } + d.enabled = &sack + } + + val := "0\n" + if *d.enabled { + // Technically, this is not quite compatible with Linux. Linux stores these + // as an integer, so if you write "2" into tcp_sack, you should get 2 back. + // Tough luck. + val = "1\n" + } + buf.WriteString(val) + return nil +} + +func (d *tcpSackData) Write(ctx context.Context, src usermem.IOSequence, offset int64) (int64, error) { + if offset != 0 { + // No need to handle partial writes thus far. + return 0, syserror.EINVAL + } + if src.NumBytes() == 0 { + return 0, nil + } + + // Limit the amount of memory allocated. + 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 n, err + } + if d.enabled == nil { + d.enabled = new(bool) + } + *d.enabled = v != 0 + return n, d.stack.SetTCPSACKEnabled(*d.enabled) +} diff --git a/pkg/sentry/vfs/file_description_impl_util.go b/pkg/sentry/vfs/file_description_impl_util.go index fb9b87fdc..a4900c170 100644 --- a/pkg/sentry/vfs/file_description_impl_util.go +++ b/pkg/sentry/vfs/file_description_impl_util.go @@ -192,21 +192,6 @@ func (DentryMetadataFileDescriptionImpl) SetStat(ctx context.Context, opts SetSt panic("illegal call to DentryMetadataFileDescriptionImpl.SetStat") } -// DynamicBytesFileDescriptionImpl may be embedded by implementations of -// FileDescriptionImpl that represent read-only regular files whose contents -// are backed by a bytes.Buffer that is regenerated when necessary, consistent -// with Linux's fs/seq_file.c:single_open(). -// -// DynamicBytesFileDescriptionImpl.SetDataSource() must be called before first -// use. -type DynamicBytesFileDescriptionImpl struct { - data DynamicBytesSource // immutable - mu sync.Mutex // protects the following fields - buf bytes.Buffer - off int64 - lastRead int64 // offset at which the last Read, PRead, or Seek ended -} - // DynamicBytesSource represents a data source for a // DynamicBytesFileDescriptionImpl. type DynamicBytesSource interface { @@ -225,6 +210,30 @@ func (s *StaticData) Generate(ctx context.Context, buf *bytes.Buffer) error { return nil } +// WritableDynamicBytesSource extends DynamicBytesSource to allow writes to the +// underlying source. +type WritableDynamicBytesSource interface { + DynamicBytesSource + + // Write sends writes to the source. + Write(ctx context.Context, src usermem.IOSequence, offset int64) (int64, error) +} + +// DynamicBytesFileDescriptionImpl may be embedded by implementations of +// FileDescriptionImpl that represent read-only regular files whose contents +// are backed by a bytes.Buffer that is regenerated when necessary, consistent +// with Linux's fs/seq_file.c:single_open(). +// +// DynamicBytesFileDescriptionImpl.SetDataSource() must be called before first +// use. +type DynamicBytesFileDescriptionImpl struct { + data DynamicBytesSource // immutable + mu sync.Mutex // protects the following fields + buf bytes.Buffer + off int64 + lastRead int64 // offset at which the last Read, PRead, or Seek ended +} + // SetDataSource must be called exactly once on fd before first use. func (fd *DynamicBytesFileDescriptionImpl) SetDataSource(data DynamicBytesSource) { fd.data = data @@ -304,6 +313,43 @@ func (fd *DynamicBytesFileDescriptionImpl) Seek(ctx context.Context, offset int6 return offset, nil } +// Preconditions: fd.mu must be locked. +func (fd *DynamicBytesFileDescriptionImpl) pwriteLocked(ctx context.Context, src usermem.IOSequence, offset int64, opts WriteOptions) (int64, error) { + if opts.Flags&^(linux.RWF_HIPRI|linux.RWF_DSYNC|linux.RWF_SYNC) != 0 { + return 0, syserror.EOPNOTSUPP + } + + writable, ok := fd.data.(WritableDynamicBytesSource) + if !ok { + return 0, syserror.EINVAL + } + n, err := writable.Write(ctx, src, offset) + if err != nil { + return 0, err + } + + // Invalidate cached data that might exist prior to this call. + fd.buf.Reset() + return n, nil +} + +// PWrite implements FileDescriptionImpl.PWrite. +func (fd *DynamicBytesFileDescriptionImpl) PWrite(ctx context.Context, src usermem.IOSequence, offset int64, opts WriteOptions) (int64, error) { + fd.mu.Lock() + n, err := fd.pwriteLocked(ctx, src, offset, opts) + fd.mu.Unlock() + return n, err +} + +// Write implements FileDescriptionImpl.Write. +func (fd *DynamicBytesFileDescriptionImpl) Write(ctx context.Context, src usermem.IOSequence, opts WriteOptions) (int64, error) { + fd.mu.Lock() + n, err := fd.pwriteLocked(ctx, src, fd.off, opts) + fd.off += n + fd.mu.Unlock() + return n, err +} + // GenericConfigureMMap may be used by most implementations of // FileDescriptionImpl.ConfigureMMap. func GenericConfigureMMap(fd *FileDescription, m memmap.Mappable, opts *memmap.MMapOpts) error { diff --git a/pkg/sentry/vfs/file_description_impl_util_test.go b/pkg/sentry/vfs/file_description_impl_util_test.go index 0f44e7c8c..8fa26418e 100644 --- a/pkg/sentry/vfs/file_description_impl_util_test.go +++ b/pkg/sentry/vfs/file_description_impl_util_test.go @@ -35,61 +35,80 @@ type fileDescription struct { FileDescriptionDefaultImpl } -// genCountFD is a read-only FileDescriptionImpl representing a regular file -// that contains the number of times its DynamicBytesSource.Generate() +// genCount contains the number of times its DynamicBytesSource.Generate() // implementation has been called. -type genCountFD struct { +type genCount struct { + count uint64 // accessed using atomic memory ops +} + +// Generate implements DynamicBytesSource.Generate. +func (g *genCount) Generate(ctx context.Context, buf *bytes.Buffer) error { + fmt.Fprintf(buf, "%d", atomic.AddUint64(&g.count, 1)) + return nil +} + +type storeData struct { + data string +} + +var _ WritableDynamicBytesSource = (*storeData)(nil) + +// Generate implements DynamicBytesSource. +func (d *storeData) Generate(ctx context.Context, buf *bytes.Buffer) error { + buf.WriteString(d.data) + return nil +} + +// Generate implements WritableDynamicBytesSource. +func (d *storeData) Write(ctx context.Context, src usermem.IOSequence, offset int64) (int64, error) { + buf := make([]byte, src.NumBytes()) + n, err := src.CopyIn(ctx, buf) + if err != nil { + return 0, err + } + + d.data = string(buf[:n]) + return 0, nil +} + +// testFD is a read-only FileDescriptionImpl representing a regular file. +type testFD struct { fileDescription DynamicBytesFileDescriptionImpl - count uint64 // accessed using atomic memory ops + data DynamicBytesSource } -func newGenCountFD(vfsObj *VirtualFilesystem) *FileDescription { +func newTestFD(vfsObj *VirtualFilesystem, statusFlags uint32, data DynamicBytesSource) *FileDescription { vd := vfsObj.NewAnonVirtualDentry("genCountFD") defer vd.DecRef() - var fd genCountFD - fd.vfsfd.Init(&fd, 0 /* statusFlags */, vd.Mount(), vd.Dentry(), &FileDescriptionOptions{}) - fd.DynamicBytesFileDescriptionImpl.SetDataSource(&fd) + var fd testFD + fd.vfsfd.Init(&fd, statusFlags, vd.Mount(), vd.Dentry(), &FileDescriptionOptions{}) + fd.DynamicBytesFileDescriptionImpl.SetDataSource(data) return &fd.vfsfd } // Release implements FileDescriptionImpl.Release. -func (fd *genCountFD) Release() { -} - -// StatusFlags implements FileDescriptionImpl.StatusFlags. -func (fd *genCountFD) StatusFlags(ctx context.Context) (uint32, error) { - return 0, nil +func (fd *testFD) Release() { } // SetStatusFlags implements FileDescriptionImpl.SetStatusFlags. -func (fd *genCountFD) SetStatusFlags(ctx context.Context, flags uint32) error { - return syserror.EPERM -} - // Stat implements FileDescriptionImpl.Stat. -func (fd *genCountFD) Stat(ctx context.Context, opts StatOptions) (linux.Statx, error) { +func (fd *testFD) Stat(ctx context.Context, opts StatOptions) (linux.Statx, error) { // Note that Statx.Mask == 0 in the return value. return linux.Statx{}, nil } // SetStat implements FileDescriptionImpl.SetStat. -func (fd *genCountFD) SetStat(ctx context.Context, opts SetStatOptions) error { +func (fd *testFD) SetStat(ctx context.Context, opts SetStatOptions) error { return syserror.EPERM } -// Generate implements DynamicBytesSource.Generate. -func (fd *genCountFD) Generate(ctx context.Context, buf *bytes.Buffer) error { - fmt.Fprintf(buf, "%d", atomic.AddUint64(&fd.count, 1)) - return nil -} - func TestGenCountFD(t *testing.T) { ctx := contexttest.Context(t) vfsObj := New() // vfs.New() - fd := newGenCountFD(vfsObj) + fd := newTestFD(vfsObj, linux.O_RDWR, &genCount{}) defer fd.DecRef() // The first read causes Generate to be called to fill the FD's buffer. @@ -130,4 +149,69 @@ func TestGenCountFD(t *testing.T) { if want := byte('3'); buf[0] != want { t.Errorf("PRead: got byte %c, wanted %c", buf[0], want) } + + // Write and PWrite fails. + if _, err := fd.Write(ctx, ioseq, WriteOptions{}); err != syserror.EINVAL { + t.Errorf("Write: got err %v, wanted %v", err, syserror.EINVAL) + } + if _, err := fd.PWrite(ctx, ioseq, 0, WriteOptions{}); err != syserror.EINVAL { + t.Errorf("Write: got err %v, wanted %v", err, syserror.EINVAL) + } +} + +func TestWritable(t *testing.T) { + ctx := contexttest.Context(t) + + vfsObj := New() // vfs.New() + fd := newTestFD(vfsObj, linux.O_RDWR, &storeData{data: "init"}) + defer fd.DecRef() + + buf := make([]byte, 10) + ioseq := usermem.BytesIOSequence(buf) + if n, err := fd.Read(ctx, ioseq, ReadOptions{}); n != 4 && err != io.EOF { + t.Fatalf("Read: got (%v, %v), wanted (4, EOF)", n, err) + } + if want := "init"; want == string(buf) { + t.Fatalf("Read: got %v, wanted %v", string(buf), want) + } + + // Test PWrite. + want := "write" + writeIOSeq := usermem.BytesIOSequence([]byte(want)) + if n, err := fd.PWrite(ctx, writeIOSeq, 0, WriteOptions{}); int(n) != len(want) && err != nil { + t.Errorf("PWrite: got err (%v, %v), wanted (%v, nil)", n, err, len(want)) + } + if n, err := fd.PRead(ctx, ioseq, 0, ReadOptions{}); int(n) != len(want) && err != io.EOF { + t.Fatalf("PRead: got (%v, %v), wanted (%v, EOF)", n, err, len(want)) + } + if want == string(buf) { + t.Fatalf("PRead: got %v, wanted %v", string(buf), want) + } + + // Test Seek to 0 followed by Write. + want = "write2" + writeIOSeq = usermem.BytesIOSequence([]byte(want)) + if n, err := fd.Seek(ctx, 0, linux.SEEK_SET); n != 0 && err != nil { + t.Errorf("Seek: got err (%v, %v), wanted (0, nil)", n, err) + } + if n, err := fd.Write(ctx, writeIOSeq, WriteOptions{}); int(n) != len(want) && err != nil { + t.Errorf("Write: got err (%v, %v), wanted (%v, nil)", n, err, len(want)) + } + if n, err := fd.PRead(ctx, ioseq, 0, ReadOptions{}); int(n) != len(want) && err != io.EOF { + t.Fatalf("PRead: got (%v, %v), wanted (%v, EOF)", n, err, len(want)) + } + if want == string(buf) { + t.Fatalf("PRead: got %v, wanted %v", string(buf), want) + } + + // Test failure if offset != 0. + if n, err := fd.Seek(ctx, 1, linux.SEEK_SET); n != 0 && err != nil { + t.Errorf("Seek: got err (%v, %v), wanted (0, nil)", n, err) + } + if n, err := fd.Write(ctx, writeIOSeq, WriteOptions{}); n != 0 && err != syserror.EINVAL { + t.Errorf("Write: got err (%v, %v), wanted (0, EINVAL)", n, err) + } + if n, err := fd.PWrite(ctx, writeIOSeq, 2, WriteOptions{}); n != 0 && err != syserror.EINVAL { + t.Errorf("PWrite: got err (%v, %v), wanted (0, EINVAL)", n, err) + } } -- cgit v1.2.3