4 files changed, 8 insertions, 2 deletions
diff --git a/pkg/sentry/fs/dev/null.go b/pkg/sentry/fs/dev/null.go
index 18dd08515..4404b97ef 100644
--- a/pkg/sentry/fs/dev/null.go
+++ b/pkg/sentry/fs/dev/null.go
@@ -97,6 +97,7 @@ func newZeroDevice(ctx context.Context, owner fs.FileOwner, mode linux.FileMode)
 func (zd *zeroDevice) GetFile(ctx context.Context, dirent *fs.Dirent, flags fs.FileFlags) (*fs.File, error) {
 	flags.Pread = true
 	flags.Pwrite = true
+	flags.NonSeekable = true
 
 	return fs.NewFile(ctx, dirent, flags, &zeroFileOperations{}), nil
 }
diff --git a/pkg/sentry/fs/file.go b/pkg/sentry/fs/file.go
index 6df7d7b4f..55ffe6c0c 100644
--- a/pkg/sentry/fs/file.go
+++ b/pkg/sentry/fs/file.go
@@ -267,7 +267,7 @@ func (f *File) Readv(ctx context.Context, dst usermem.IOSequence) (int64, error)
 
 	reads.Increment()
 	n, err := f.FileOperations.Read(ctx, f, dst, f.offset)
-	if n > 0 {
+	if n > 0 && !f.flags.NonSeekable {
 		atomic.AddInt64(&f.offset, n)
 	}
 	f.mu.Unlock()
@@ -330,7 +330,7 @@ func (f *File) Writev(ctx context.Context, src usermem.IOSequence) (int64, error
 
 	// We must hold the lock during the write.
 	n, err := f.FileOperations.Write(ctx, f, src, f.offset)
-	if n >= 0 {
+	if n >= 0 && !f.flags.NonSeekable {
 		atomic.StoreInt64(&f.offset, f.offset+n)
 	}
 	f.mu.Unlock()
diff --git a/pkg/sentry/fs/flags.go b/pkg/sentry/fs/flags.go
index f31bfa0db..1278f9c78 100644
--- a/pkg/sentry/fs/flags.go
+++ b/pkg/sentry/fs/flags.go
@@ -57,6 +57,9 @@ type FileFlags struct {
 	// Linux sets this flag for all files. Since gVisor is only compatible
 	// with 64-bit Linux, it also sets this flag for all files.
 	LargeFile bool
+
+	// NonSeekable indicates that file.offset isn't used.
+	NonSeekable bool
 }
 
 // SettableFileFlags is a subset of FileFlags above that can be changed
diff --git a/pkg/sentry/fs/fs_state_autogen.go b/pkg/sentry/fs/fs_state_autogen.go
index f547ccd0f..5aa800be4 100755
--- a/pkg/sentry/fs/fs_state_autogen.go
+++ b/pkg/sentry/fs/fs_state_autogen.go
@@ -353,6 +353,7 @@ func (x *FileFlags) save(m state.Map) {
 	m.Save("Directory", &x.Directory)
 	m.Save("Async", &x.Async)
 	m.Save("LargeFile", &x.LargeFile)
+	m.Save("NonSeekable", &x.NonSeekable)
 }
 
 func (x *FileFlags) afterLoad() {}
@@ -368,6 +369,7 @@ func (x *FileFlags) load(m state.Map) {
 	m.Load("Directory", &x.Directory)
 	m.Load("Async", &x.Async)
 	m.Load("LargeFile", &x.LargeFile)
+	m.Load("NonSeekable", &x.NonSeekable)
 }
 
 func (x *Inode) beforeSave() {}