qbit/go
1
0
Fork 0
mirror of https://github.com/golang/go synced 2024-11-12 07:40:23 -07:00
Code Releases Activity

image/gif: be stricter on parsing graphic control extensions.

Browse Source 
See Section 23. Graphic Control Extension of the spec:
https://www.w3.org/Graphics/GIF/spec-gif89a.txt

Change-Id: Ie78b4ff4aa97e1b332ade67ae4fa25f7c0770610
Reviewed-on: https://go-review.googlesource.com/22547
Reviewed-by: Rob Pike <r@golang.org>
This commit is contained in:
Nigel Tao 2016-04-28 19:01:48 +10:00
parent cb97fd7741
commit ac0ee77d63
2 changed files with 7 additions and 1 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

6
src/image/gif/reader.go
View File

@ -349,6 +349,9 @@ func (d *decoder) readGraphicControl() error {
if _, err := io.ReadFull(d.r, d.tmp[:6]); err != nil {
return fmt.Errorf("gif: can't read graphic control: %s", err)
}
if d.tmp[0] != 4 {
return fmt.Errorf("gif: invalid graphic control extension block size: %d", d.tmp[0])
}
flags := d.tmp[1]
d.disposalMethod = (flags & gcDisposalMethodMask) >> 2
d.delayTime = int(d.tmp[2]) | int(d.tmp[3])<<8
@ -356,6 +359,9 @@ func (d *decoder) readGraphicControl() error {
d.transparentIndex = d.tmp[4]
d.hasTransparentIndex = true
}
if d.tmp[5] != 0 {
return fmt.Errorf("gif: invalid graphic control extension block terminator: %d", d.tmp[5])
}
return nil
}

2
src/image/gif/reader_test.go
View File

@ -97,7 +97,7 @@ func TestTransparentIndex(t *testing.T) {
for transparentIndex := 0; transparentIndex < 3; transparentIndex++ {
if transparentIndex < 2 {
// Write the graphic control for the transparent index.
b.WriteString("\x21\xf9\x00\x01\x00\x00")
b.WriteString("\x21\xf9\x04\x01\x00\x00")
b.WriteByte(byte(transparentIndex))
b.WriteByte(0)
}