From 52758e16e0d1e67b3cdd56e04abfce663607ac42 Mon Sep 17 00:00:00 2001
From: Bhasker Hariharan <bhaskerh@google.com>
Date: Mon, 16 Mar 2020 08:02:05 -0700
Subject: Prevent vnetHdr from escaping in WritePacket.
PiperOrigin-RevId: 301157950
---
pkg/tcpip/link/fdbased/endpoint.go | 2 +-
pkg/tcpip/link/fdbased/endpoint_unsafe.go | 9 +++++----
2 files changed, 6 insertions(+), 5 deletions(-)
(limited to 'pkg/tcpip')
diff --git a/pkg/tcpip/link/fdbased/endpoint.go b/pkg/tcpip/link/fdbased/endpoint.go
index a753fb243..3b36b9673 100644
--- a/pkg/tcpip/link/fdbased/endpoint.go
+++ b/pkg/tcpip/link/fdbased/endpoint.go
@@ -407,7 +407,6 @@ func (e *endpoint) WritePacket(r *stack.Route, gso *stack.GSO, protocol tcpip.Ne
if e.Capabilities()&stack.CapabilityHardwareGSO != 0 {
vnetHdr := virtioNetHdr{}
- vnetHdrBuf := vnetHdrToByteSlice(&vnetHdr)
if gso != nil {
vnetHdr.hdrLen = uint16(pkt.Header.UsedLength())
if gso.NeedsCsum {
@@ -428,6 +427,7 @@ func (e *endpoint) WritePacket(r *stack.Route, gso *stack.GSO, protocol tcpip.Ne
}
}
+ vnetHdrBuf := vnetHdrToByteSlice(&vnetHdr)
return rawfile.NonBlockingWrite3(e.fds[0], vnetHdrBuf, pkt.Header.View(), pkt.Data.ToView())
}
diff --git a/pkg/tcpip/link/fdbased/endpoint_unsafe.go b/pkg/tcpip/link/fdbased/endpoint_unsafe.go
index 97a477b61..d81858353 100644
--- a/pkg/tcpip/link/fdbased/endpoint_unsafe.go
+++ b/pkg/tcpip/link/fdbased/endpoint_unsafe.go
@@ -24,9 +24,10 @@ import (
const virtioNetHdrSize = int(unsafe.Sizeof(virtioNetHdr{}))
func vnetHdrToByteSlice(hdr *virtioNetHdr) (slice []byte) {
- sh := (*reflect.SliceHeader)(unsafe.Pointer(&slice))
- sh.Data = uintptr(unsafe.Pointer(hdr))
- sh.Len = virtioNetHdrSize
- sh.Cap = virtioNetHdrSize
+ *(*reflect.SliceHeader)(unsafe.Pointer(&slice)) = reflect.SliceHeader{
+ Data: uintptr((unsafe.Pointer(hdr))),
+ Len: virtioNetHdrSize,
+ Cap: virtioNetHdrSize,
+ }
return
}
--
cgit v1.2.3