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| author | Brian Geffon <bgeffon@google.com> | 2018-06-11 16:39:39 -0700 |
|---|---|---|
| committer | Shentubot <shentubot@google.com> | 2018-06-11 16:40:38 -0700 |
| commit | ab2c2575d61266725ce13dff570663464a171342 (patch) | |
| tree | 619eb5019fe4ea98d47254c9c419368bb57a5857 /pkg/sentry | |
| parent | 0412f17e06670fb1f1d1d85ddd73bbadde40c087 (diff) | |
Rpcinet is incorrectly handling MSG_TRUNC with SOCK_STREAM
SOCK_STREAM has special behavior with respect to MSG_TRUNC. Specifically,
the data isn't actually copied back out to userspace when MSG_TRUNC is
provided on a SOCK_STREAM.
According to tcp(7): "Since version 2.4, Linux supports the use of
MSG_TRUNC in the flags argument of recv(2) (and recvmsg(2)). This flag
causes the received bytes of data to be discarded, rather than passed
back in a caller-supplied buffer."
PiperOrigin-RevId: 200134860
Change-Id: I70f17a5f60ffe7794c3f0cfafd131c069202e90d
Diffstat (limited to 'pkg/sentry')
| -rw-r--r-- | pkg/sentry/socket/rpcinet/socket.go | 20 |
1 files changed, 14 insertions, 6 deletions
diff --git a/pkg/sentry/socket/rpcinet/socket.go b/pkg/sentry/socket/rpcinet/socket.go index ffe947500..6f1a4fe01 100644 --- a/pkg/sentry/socket/rpcinet/socket.go +++ b/pkg/sentry/socket/rpcinet/socket.go @@ -465,9 +465,13 @@ func (s *socketOperations) RecvMsg(t *kernel.Task, dst usermem.IOSequence, flags res, err := rpcRecvMsg(t, req) if err == nil { - n, e := dst.CopyOut(t, res.Data) - if e == nil && n != len(res.Data) { - panic("CopyOut failed to copy full buffer") + var e error + var n int + if len(res.Data) > 0 { + n, e = dst.CopyOut(t, res.Data) + if e == nil && n != len(res.Data) { + panic("CopyOut failed to copy full buffer") + } } return int(res.Length), res.Address.GetAddress(), res.Address.GetLength(), socket.ControlMessages{}, syserr.FromError(e) } @@ -484,9 +488,13 @@ func (s *socketOperations) RecvMsg(t *kernel.Task, dst usermem.IOSequence, flags for { res, err := rpcRecvMsg(t, req) if err == nil { - n, e := dst.CopyOut(t, res.Data) - if e == nil && n != len(res.Data) { - panic("CopyOut failed to copy full buffer") + var e error + var n int + if len(res.Data) > 0 { + n, e = dst.CopyOut(t, res.Data) + if e == nil && n != len(res.Data) { + panic("CopyOut failed to copy full buffer") + } } return int(res.Length), res.Address.GetAddress(), res.Address.GetLength(), socket.ControlMessages{}, syserr.FromError(e) } |