diff --git a/pkg/sentry/socket/epsocket/epsocket.go b/pkg/sentry/socket/epsocket/epsocket.go index 3e05e40fe..25adca090 100644 --- a/pkg/sentry/socket/epsocket/epsocket.go +++ b/pkg/sentry/socket/epsocket/epsocket.go @@ -415,13 +415,13 @@ func (s *SocketOperations) Read(ctx context.Context, _ *fs.File, dst usermem.IOS // WriteTo implements fs.FileOperations.WriteTo. func (s *SocketOperations) WriteTo(ctx context.Context, _ *fs.File, dst io.Writer, count int64, dup bool) (int64, error) { s.readMu.Lock() - defer s.readMu.Unlock() // Copy as much data as possible. done := int64(0) for count > 0 { // This may return a blocking error. if err := s.fetchReadView(); err != nil { + s.readMu.Unlock() return done, err.ToError() } @@ -434,16 +434,18 @@ func (s *SocketOperations) WriteTo(ctx context.Context, _ *fs.File, dst io.Write // supported by any Linux system calls, but the // expectation is that now a caller will call read to // actually remove these bytes from the socket. - return done, nil + break } // Drop that part of the view. s.readView.TrimFront(n) if err != nil { + s.readMu.Unlock() return done, err } } + s.readMu.Unlock() return done, nil } @@ -549,7 +551,11 @@ func (r *readerPayload) Payload(size int) ([]byte, *tcpip.Error) { // ReadFrom implements fs.FileOperations.ReadFrom. func (s *SocketOperations) ReadFrom(ctx context.Context, _ *fs.File, r io.Reader, count int64) (int64, error) { f := &readerPayload{ctx: ctx, r: r, count: count} - n, resCh, err := s.Endpoint.Write(f, tcpip.WriteOptions{}) + n, resCh, err := s.Endpoint.Write(f, tcpip.WriteOptions{ + // Reads may be destructive but should be very fast, + // so we can't release the lock while copying data. + Atomic: true, + }) if err == tcpip.ErrWouldBlock { return 0, syserror.ErrWouldBlock } @@ -561,9 +567,7 @@ func (s *SocketOperations) ReadFrom(ctx context.Context, _ *fs.File, r io.Reader } n, _, err = s.Endpoint.Write(f, tcpip.WriteOptions{ - // Reads may be destructive but should be very fast, - // so we can't release the lock while copying data. - Atomic: true, + Atomic: true, // See above. }) } if err == tcpip.ErrWouldBlock {