fix(graphics): validate placement scrolling

commit: a67301cbb68aa950cc595694fd11e246c88eff68
author: brice · 57d ago · 2026-08-26 15:30 UTC
parent: 47ca903
signature: GPG VerifiedCD88F9E564E0102646FB6077A1A07C7C7C3E349D · arch-gpg Verified for the committer email

3 files · +42 -2

M protocol/kittygraphics/session.go +1 -1


@@ -407,7 +407,7 @@ func decodeImagePayload(payload []byte, controls Controls, limits Limits) ([]byt
407	407		if err != nil {
408	408		return nil, fmt.Errorf("%w: zlib: %v", ErrInvalidCommand, err)
409	409		}
410		-	defer zr.Close()
	410	+	defer func() { _ = zr.Close() }()
411	411		limit := limits.MaxDecodedBytes
412	412		if limit >= math.MaxInt64 {
413	413		limit = math.MaxInt64 - 1


@@ -407,7 +407,7 @@ func decodeImagePayload(payload []byte, controls Controls, limits Limits) ([]byt
407		if err != nil {	407		if err != nil {
408		return nil, fmt.Errorf("%w: zlib: %v", ErrInvalidCommand, err)	408		return nil, fmt.Errorf("%w: zlib: %v", ErrInvalidCommand, err)
409		}	409		}
410	-	defer zr.Close()	410	+	defer func() { _ = zr.Close() }()
411		limit := limits.MaxDecodedBytes	411		limit := limits.MaxDecodedBytes
412		if limit >= math.MaxInt64 {	412		if limit >= math.MaxInt64 {
413		limit = math.MaxInt64 - 1	413		limit = math.MaxInt64 - 1

M screen_graphics_test.go +34 -0


@@ -2,6 +2,7 @@ package vt
2	2
3	3		import (
4	4		"encoding/base64"
	5	+	"math"
5	6		"strconv"
6	7		"testing"
7	8

@@ -283,3 +284,36 @@ func TestScreenKittyPlacementScrollsWithTallImageCursorAdvance(t *testing.T) {
283	284		require.Equal(t, 4, screen.CursorRow())
284	285		require.Equal(t, 2, screen.CursorCol())
285	286		}
	287	+
	288	+	func TestScreenKittyPlacementScrollsOnlyWhenContainedInRegion(t *testing.T) {
	289	+	screen := NewScreen(10, 6)
	290	+	screen.SetGeometry(Geometry{Cols: 10, Rows: 6, PixelWidth: 100, PixelHeight: 60})
	291	+	screen.Write([]byte("\x1b[2;5r"))
	292	+
	293	+	insidePayload := base64.RawStdEncoding.EncodeToString(make([]byte, 1104))
	294	+	screen.Write([]byte("\x1b[3;1H\x1b_Ga=T,i=1,f=32,s=1,v=10,C=1;" + insidePayload + "\x1b\\"))
	295	+	straddlingPayload := base64.RawStdEncoding.EncodeToString(make([]byte, 1204))
	296	+	screen.Write([]byte("\x1b[1;1H\x1b_Ga=T,i=2,f=32,s=1,v=20,Y=5,C=1;" + straddlingPayload + "\x1b\\"))
	297	+
	298	+	screen.Write([]byte("\x1b[S"))
	299	+
	300	+	placements := screen.GraphicsSnapshot().Placements()
	301	+	require.Len(t, placements, 2)
	302	+	require.Equal(t, graphics.PixelRect{X: 0, Y: 10, Width: 1, Height: 10}, placements[0].Destination(), "a placement contained in the margin must scroll")
	303	+	require.Equal(t, graphics.PixelRect{X: 0, Y: 5, Width: 1, Height: 20}, placements[1].Destination(), "a placement crossing the margin must remain fixed")
	304	+	}
	305	+
	306	+	func TestScreenKittyPlacementScrollSkipsBottomEdgeOverflow(t *testing.T) {
	307	+	screen := NewScreen(1, 2)
	308	+	screen.SetGeometry(Geometry{Cols: 1, Rows: 2, PixelWidth: 10, PixelHeight: 20})
	309	+	payload := base64.RawStdEncoding.EncodeToString(make([]byte, 1104))
	310	+	screen.Write([]byte("\x1b_Ga=T,i=1,f=32,s=1,v=10,C=1;" + payload + "\x1b\\"))
	311	+	placement := screen.GraphicsSnapshot().Placements()[0]
	312	+	nearLimit := graphics.PixelRect{X: 0, Y: math.MaxInt64 - 11, Width: 1, Height: 10}
	313	+	require.NoError(t, screen.graphics.scene.UpdatePlacement(placement.ID(), graphics.PlacementSpec{Destination: nearLimit}))
	314	+
	315	+	require.NotPanics(t, func() { screen.Write([]byte("\x1b[T")) })
	316	+
	317	+	placement = screen.GraphicsSnapshot().Placements()[0]
	318	+	require.Equal(t, nearLimit, placement.Destination())
	319	+	}


@@ -2,6 +2,7 @@ package vt
2		2
3	import (	3		import (
4	"encoding/base64"	4		"encoding/base64"
		5	+	"math"
5	"strconv"	6		"strconv"
6	"testing"	7		"testing"
7		8

@@ -283,3 +284,36 @@ func TestScreenKittyPlacementScrollsWithTallImageCursorAdvance(t *testing.T) {
283	require.Equal(t, 4, screen.CursorRow())	284		require.Equal(t, 4, screen.CursorRow())
284	require.Equal(t, 2, screen.CursorCol())	285		require.Equal(t, 2, screen.CursorCol())
285	}	286		}
		287	+
		288	+	func TestScreenKittyPlacementScrollsOnlyWhenContainedInRegion(t *testing.T) {
		289	+	screen := NewScreen(10, 6)
		290	+	screen.SetGeometry(Geometry{Cols: 10, Rows: 6, PixelWidth: 100, PixelHeight: 60})
		291	+	screen.Write([]byte("\x1b[2;5r"))
		292	+
		293	+	insidePayload := base64.RawStdEncoding.EncodeToString(make([]byte, 1104))
		294	+	screen.Write([]byte("\x1b[3;1H\x1b_Ga=T,i=1,f=32,s=1,v=10,C=1;" + insidePayload + "\x1b\\"))
		295	+	straddlingPayload := base64.RawStdEncoding.EncodeToString(make([]byte, 1204))
		296	+	screen.Write([]byte("\x1b[1;1H\x1b_Ga=T,i=2,f=32,s=1,v=20,Y=5,C=1;" + straddlingPayload + "\x1b\\"))
		297	+
		298	+	screen.Write([]byte("\x1b[S"))
		299	+
		300	+	placements := screen.GraphicsSnapshot().Placements()
		301	+	require.Len(t, placements, 2)
		302	+	require.Equal(t, graphics.PixelRect{X: 0, Y: 10, Width: 1, Height: 10}, placements[0].Destination(), "a placement contained in the margin must scroll")
		303	+	require.Equal(t, graphics.PixelRect{X: 0, Y: 5, Width: 1, Height: 20}, placements[1].Destination(), "a placement crossing the margin must remain fixed")
		304	+	}
		305	+
		306	+	func TestScreenKittyPlacementScrollSkipsBottomEdgeOverflow(t *testing.T) {
		307	+	screen := NewScreen(1, 2)
		308	+	screen.SetGeometry(Geometry{Cols: 1, Rows: 2, PixelWidth: 10, PixelHeight: 20})
		309	+	payload := base64.RawStdEncoding.EncodeToString(make([]byte, 1104))
		310	+	screen.Write([]byte("\x1b_Ga=T,i=1,f=32,s=1,v=10,C=1;" + payload + "\x1b\\"))
		311	+	placement := screen.GraphicsSnapshot().Placements()[0]
		312	+	nearLimit := graphics.PixelRect{X: 0, Y: math.MaxInt64 - 11, Width: 1, Height: 10}
		313	+	require.NoError(t, screen.graphics.scene.UpdatePlacement(placement.ID(), graphics.PlacementSpec{Destination: nearLimit}))
		314	+
		315	+	require.NotPanics(t, func() { screen.Write([]byte("\x1b[T")) })
		316	+
		317	+	placement = screen.GraphicsSnapshot().Placements()[0]
		318	+	require.Equal(t, nearLimit, placement.Destination())
		319	+	}

M screen_scroll.go +7 -1


@@ -2,6 +2,7 @@ package vt
2	2
3	3		import (
4	4		"errors"
	5	+	"fmt"
5	6		"math"
6	7
7	8		renderer "github.com/bnema/vev-vt/core"

@@ -175,12 +176,17 @@ func (s *Screen) scrollGraphicsRegion(top, bottom, rows int) {
175	176		continue
176	177		}
177	178		destination.Y += delta
	179	+	if _, valid := destination.Bottom(); !valid {
	180	+	continue
	181	+	}
178	182		spec := placement.Spec()
179	183		spec.Destination = destination
180	184		operations = append(operations, graphics.Operation{Kind: graphics.OperationUpdatePlacement, PlacementID: placement.ID(), Placement: spec})
181	185		}
182	186		if len(operations) != 0 {
183		-	_ = s.graphics.scene.Apply(operations...)
	187	+	if err := s.graphics.scene.Apply(operations...); err != nil {
	188	+	panic(fmt.Errorf("scroll graphics placements: %w", err))
	189	+	}
184	190		}
185	191		}
186	192

 import (
 	"errors"
+	"fmt"
 	"math"
 	renderer "github.com/bnema/vev-vt/core"
 			continue
 		}
 		destination.Y += delta
+		if _, valid := destination.Bottom(); !valid {
+			continue
+		}
 		spec := placement.Spec()
 		spec.Destination = destination
 		operations = append(operations, graphics.Operation{Kind: graphics.OperationUpdatePlacement, PlacementID: placement.ID(), Placement: spec})
 	}
 	if len(operations) != 0 {
-		_ = s.graphics.scene.Apply(operations...)
+		if err := s.graphics.scene.Apply(operations...); err != nil {
+			panic(fmt.Errorf("scroll graphics placements: %w", err))
+		}
 	}
 }