sentry: save copy of tcp segment's delivered views to avoid in-struct pointers.

PiperOrigin-RevId: 224033238
Change-Id: Ie5b1854b29340843b02c123766d290a8738d7631

2 files changed, 11 insertions, 2 deletions

diff --git a/pkg/tcpip/transport/tcp/segment.go b/pkg/tcpip/transport/tcp/segment.go
index fc87a05fd..87c6d7d20 100644
--- a/pkg/tcpip/transport/tcp/segment.go
+++ b/pkg/tcpip/transport/tcp/segment.go
@@ -46,7 +46,7 @@ type segment struct {
 	data   buffer.VectorisedView     `state:".(buffer.VectorisedView)"`
 	// views is used as buffer for data when its length is large
 	// enough to store a VectorisedView.
-	views [8]buffer.View
+	views [8]buffer.View `state:"nosave"`
 	// viewToDeliver keeps track of the next View that should be
 	// delivered by the Read endpoint.
 	viewToDeliver  int
diff --git a/pkg/tcpip/transport/tcp/segment_state.go b/pkg/tcpip/transport/tcp/segment_state.go
index 46b6d85a6..d4bd6cf95 100644
--- a/pkg/tcpip/transport/tcp/segment_state.go
+++ b/pkg/tcpip/transport/tcp/segment_state.go
@@ -22,7 +22,16 @@ import (
 func (s *segment) saveData() buffer.VectorisedView {
 	// We cannot save s.data directly as s.data.views may alias to s.views,
 	// which is not allowed by state framework (in-struct pointer).
-	return s.data.Clone(nil)
+	v := make([]buffer.View, len(s.data.Views()))
+	// For views already delivered, we cannot save them directly as they may
+	// have already been sliced and saved elsewhere (e.g., readViews).
+	for i := 0; i < s.viewToDeliver; i++ {
+		v[i] = append([]byte(nil), s.data.Views()[i]...)
+	}
+	for i := s.viewToDeliver; i < len(v); i++ {
+		v[i] = s.data.Views()[i]
+	}
+	return buffer.NewVectorisedView(s.data.Size(), v)
 }
 
 // loadData is invoked by stateify.