diff options
| -rw-r--r-- | pkg/sentry/socket/netlink/socket.go | 22 |
1 files changed, 22 insertions, 0 deletions
diff --git a/pkg/sentry/socket/netlink/socket.go b/pkg/sentry/socket/netlink/socket.go index d0aab293d..b2732ca29 100644 --- a/pkg/sentry/socket/netlink/socket.go +++ b/pkg/sentry/socket/netlink/socket.go @@ -28,6 +28,7 @@ import ( "gvisor.dev/gvisor/pkg/sentry/fs/fsutil" "gvisor.dev/gvisor/pkg/sentry/kernel" ktime "gvisor.dev/gvisor/pkg/sentry/kernel/time" + "gvisor.dev/gvisor/pkg/sentry/safemem" "gvisor.dev/gvisor/pkg/sentry/socket" "gvisor.dev/gvisor/pkg/sentry/socket/netlink/port" "gvisor.dev/gvisor/pkg/sentry/socket/unix" @@ -416,6 +417,24 @@ func (s *Socket) RecvMsg(t *kernel.Task, dst usermem.IOSequence, flags int, have Peek: flags&linux.MSG_PEEK != 0, } + // If MSG_TRUNC is set with a zero byte destination then we still need + // to read the message and discard it, or in the case where MSG_PEEK is + // set, leave it be. In both cases the full message length must be + // returned. However, the memory manager for the destination will not read + // the endpoint if the destination is zero length. + // + // In order for the endpoint to be read when the destination size is zero, + // we must cause a read of the endpoint by using a separate fake zero + // length block sequence and calling the EndpointReader directly. + if trunc && dst.Addrs.NumBytes() == 0 { + // Perform a read to a zero byte block sequence. We can ignore the + // original destination since it was zero bytes. The length returned by + // ReadToBlocks is ignored and we return the full message length to comply + // with MSG_TRUNC. + _, err := r.ReadToBlocks(safemem.BlockSeqOf(safemem.BlockFromSafeSlice(make([]byte, 0)))) + return int(r.MsgSize), linux.MSG_TRUNC, from, fromLen, socket.ControlMessages{}, syserr.FromError(err) + } + if n, err := dst.CopyOutFrom(t, &r); err != syserror.ErrWouldBlock || flags&linux.MSG_DONTWAIT != 0 { var mflags int if n < int64(r.MsgSize) { @@ -499,6 +518,9 @@ func (s *Socket) sendResponse(ctx context.Context, ms *MessageSet) *syserr.Error PortID: uint32(ms.PortID), }) + // Add the dump_done_errno payload. + m.Put(int64(0)) + _, notify, err := s.connection.Send([][]byte{m.Finalize()}, transport.ControlMessages{}, tcpip.FullAddress{}) if err != nil && err != syserr.ErrWouldBlock { return err |