encoding/asn1: incorrectly handles incorrect utf8 strings

[dvyukov]

The following program crashes with "Marshal: asn1: string not valid UTF-8" panic:

package main

import "encoding/asn1"

func main() {
    data := []byte("0\x05\f\x03a\xc9c")
    v := X{}
    _, err := asn1.Unmarshal(data, &v)
    if err != nil {
        panic("Unmarshal: " + err.Error())
    }
    _, err = asn1.Marshal(v)
    if err != nil {
        panic("Marshal: " + err.Error())
    }
}

type X struct {
    S string //`asn1:"utf8"`
}

The string must either be not decoded successfully or encoded successfully.

If the utf8 tag is uncommented, then program finishes successfully. This also looks wrong as the string is not valid utf8.

on commit b0532a9

[agl]

Thanks for that. Fix is at https://go-review.googlesource.com/11056 although I think I'll leave it until after 1.5. It's a little risky.

[gopherbot]

CL https://golang.org/cl/11056 mentions this issue.