x/image/tiff: integer divide by zero

[dvyukov]

Run the following program on the following input:

package main

import (
    "bytes"
    "io/ioutil"
    "os"
    "golang.org/x/image/tiff"
)

func main() {
    data, _ := ioutil.ReadFile(os.Args[1])
    img, err := tiff.Decode(bytes.NewReader(data))
    if err != nil {
        return
    }
    var w bytes.Buffer
    err = tiff.Encode(&w, img, nil)
    if err != nil {
        panic(err)
    }
}

https://drive.google.com/file/d/0B20Uwp8Hs1oCNkpVc2VEdDE0RmM/view?usp=sharing

It crashes with:

panic: runtime error: integer divide by zero
[signal 0x8 code=0x1 addr=0x45cd86 pc=0x45cd86]

goroutine 1 [running]:
runtime.gopanic(0x52ae80, 0xc20800e230)
    src/runtime/panic.go:477 +0x3fe fp=0xc208041668 sp=0xc2080415e8
runtime.panicdivide()
    src/runtime/panic.go:24 +0x52 fp=0xc208041690 sp=0xc208041668
runtime.sigpanic()
    src/runtime/sigpanic_unix.go:31 +0x1dd fp=0xc2080416e0 sp=0xc208041690
golang.org/x/image/tiff.Decode(0x7f4174bb52d8, 0xc208014480, 0x7f4174bb5380, 0xc2080104c0, 0x0, 0x0)
    src/golang.org/x/image/tiff/reader.go:547 +0x6c6 fp=0xc208041ed0 sp=0xc2080416e0
main.main()
    /tmp/tiff.go:12 +0x132 fp=0xc208041f90 sp=0xc208041ed0

I am on commit 65a798f031fd31a65574938bed2ec44c2bcba496

[osocurioso]

Sent http://golang.org/cl/9182.

The offending data has zero ImageWidth, which causes the panic.

The data also has an IFD where tags are not sorted in ascending order. According to section 2 of the TIFF spec this should not be supported. Should I file an issue?

[nigeltao]

Yes, please file an issue.

[nigeltao]

CC'ing @bsiegert