diff options
Diffstat (limited to 'pkg/sentry/socket/unix/unix.go')
| -rw-r--r-- | pkg/sentry/socket/unix/unix.go | 23 |
1 files changed, 21 insertions, 2 deletions
diff --git a/pkg/sentry/socket/unix/unix.go b/pkg/sentry/socket/unix/unix.go index 885758054..91effe89a 100644 --- a/pkg/sentry/socket/unix/unix.go +++ b/pkg/sentry/socket/unix/unix.go @@ -544,8 +544,27 @@ func (s *SocketOperations) RecvMsg(t *kernel.Task, dst usermem.IOSequence, flags if senderRequested { r.From = &tcpip.FullAddress{} } + + doRead := func() (int64, error) { + return dst.CopyOutFrom(t, &r) + } + + // 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. + if trunc && dst.Addrs.NumBytes() == 0 { + doRead = func() (int64, error) { + err := r.Truncate() + // Always return zero for bytes read since the destination size is + // zero. + return 0, err + } + + } + var total int64 - if n, err := dst.CopyOutFrom(t, &r); err != syserror.ErrWouldBlock || dontWait { + if n, err := doRead(); err != syserror.ErrWouldBlock || dontWait { var from linux.SockAddr var fromLen uint32 if r.From != nil && len([]byte(r.From.Addr)) != 0 { @@ -580,7 +599,7 @@ func (s *SocketOperations) RecvMsg(t *kernel.Task, dst usermem.IOSequence, flags defer s.EventUnregister(&e) for { - if n, err := dst.CopyOutFrom(t, &r); err != syserror.ErrWouldBlock { + if n, err := doRead(); err != syserror.ErrWouldBlock { var from linux.SockAddr var fromLen uint32 if r.From != nil { |