panic: runtime error: index out of range in bcjX86Filter

[ebfe]

package main

import (
    "bytes"
    "encoding/hex"
    "fmt"
    "io/ioutil"

    "xi2.org/x/xz"
)

func main() {
    in, err := hex.DecodeString(`fd377a585a000004e6d6b4460201040021010800d2b974cbe0303030305d3030914584683bdedea84b03d83553a49173a3e51b1e5b1d4af106c1ae79ea4562760c29cd4bafb0003030303030303030303030303030303030303030303030`)
    if err != nil {
        panic(err)
    }

    r, err := xz.NewReader(bytes.NewReader(in), 0)
    if err != nil {
        fmt.Println(err)
    }
    _, err = ioutil.ReadAll(r)
    if err != nil {
        fmt.Println(err)
    }
}

panic: runtime error: index out of range [recovered]
    panic: runtime error: index out of range

goroutine 1 [running]:
io/ioutil.readAll.func1(0xc82003be48)
    /src/go/src/io/ioutil/ioutil.go:30 +0x11e
xi2.org/x/xz.bcjX86Filter(0xc820054070, 0xc82009a000, 0x49, 0x2000, 0x10000)
    /go/src/xi2.org/x/xz/dec_bcj.go:111 +0x3eb
xi2.org/x/xz.bcjApply(0xc820054070, 0xc82009a000, 0x49, 0x2000, 0xc82003ba40)
    /go/src/xi2.org/x/xz/dec_bcj.go:289 +0x8b
xi2.org/x/xz.xzDecBCJRun(0xc820054070, 0xc82009e000, 0xc82005a0c0, 0x10000)
    /go/src/xi2.org/x/xz/dec_bcj.go:370 +0x4fa
xi2.org/x/xz.decBlock(0xc82009c000, 0xc82005a0c0, 0xc82007b801)
    /go/src/xi2.org/x/xz/dec_stream.go:251 +0x7a
xi2.org/x/xz.decMain(0xc82009c000, 0xc82005a0c0, 0x5e)
    /go/src/xi2.org/x/xz/dec_stream.go:651 +0x56b
xi2.org/x/xz.xzDecRun(0xc82009c000, 0xc82005a0c0, 0x2000)
    /go/src/xi2.org/x/xz/dec_stream.go:755 +0x41
xi2.org/x/xz.(*Reader).decode(0xc8200a6000, 0xc8200a6020)
    /go/src/xi2.org/x/xz/reader.go:117 +0x2c9
xi2.org/x/xz.(*Reader).Read(0xc8200a6000, 0xc8200b4000, 0x200, 0x200, 0x0, 0x0, 0x0)
    /go/src/xi2.org/x/xz/reader.go:163 +0x370
bytes.(*Buffer).ReadFrom(0xc82003bda0, 0x7f0d9782d1e8, 0xc8200a6000, 0x0, 0x0, 0x0)
    /src/go/src/bytes/buffer.go:173 +0x23f
io/ioutil.readAll(0x7f0d9782d1e8, 0xc8200a6000, 0x200, 0x0, 0x0, 0x0, 0x0, 0x0)
    /src/go/src/io/ioutil/ioutil.go:33 +0x154
io/ioutil.ReadAll(0x7f0d9782d1e8, 0xc8200a6000, 0x0, 0x0, 0x0, 0x0, 0x0)
    /src/go/src/io/ioutil/ioutil.go:42 +0x51
main.main()
    /t.go:22 +0x277
exit status 2

found using https://github.com/dvyukov/go-fuzz.

[xi2]

I should have said thank you for reporting this, and let me know if you come across any more like it. In this case it was an error I made in my C->Go translation.