Input Causes Panic: "wÔΩø\xdc<<070005000\n"

[BrianHicks]

I've found a crashing input in HCL as of d7400db. Here's an SSCCE demonstrating the problem.

package main

import (
    "github.com/hashicorp/hcl"
)

var (
    data =  "wÔΩø\xdc<<070005000\n"
)

func main() {
    var out interface{}
    hcl.Unmarshal([]byte(data), &out)
}

When run, this gives the following output:

illegal
panic: regexp: Compile("[[:space:]]*\xdc<<070005\\z"): error parsing regexp: invalid UTF-8: `‹<<070005\z`

goroutine 1 [running]:
panic(0x19b960, 0xc82000a420)
    /var/folders/f6/l26tk3xs5pjczcd5k5pcrmk00000gn/T/go-fuzz-build846495901/src/runtime/panic.go:481 +0x3e6
regexp.MustCompile(0xc8200102c0, 0x17, 0xc820041618)
    /var/folders/f6/l26tk3xs5pjczcd5k5pcrmk00000gn/T/go-fuzz-build846495901/src/regexp/regexp.go:232 +0x1d5
github.com/hashicorp/hcl/hcl/scanner.(*Scanner).scanHeredoc(0xc820072d00)
    /var/folders/f6/l26tk3xs5pjczcd5k5pcrmk00000gn/T/go-fuzz-build846495901/src/github.com/hashicorp/hcl/hcl/scanner/scanner.go:433 +0xc6a
github.com/hashicorp/hcl/hcl/scanner.(*Scanner).Scan(0xc820072d00, 0x0, 0x0, 0x0, 0x0, 0x0, 0x0, 0x0, 0x0, 0x0)
    /var/folders/f6/l26tk3xs5pjczcd5k5pcrmk00000gn/T/go-fuzz-build846495901/src/github.com/hashicorp/hcl/hcl/scanner/scanner.go:180 +0xa74
github.com/hashicorp/hcl/hcl/parser.(*Parser).scan(0xc820041c88, 0x0, 0x0, 0x0, 0x0, 0x0, 0x0, 0x0, 0x0, 0x0)
    /var/folders/f6/l26tk3xs5pjczcd5k5pcrmk00000gn/T/go-fuzz-build846495901/src/github.com/hashicorp/hcl/hcl/parser/parser.go:376 +0x156
github.com/hashicorp/hcl/hcl/parser.(*Parser).objectKey(0xc820041c88, 0x0, 0x0, 0x0, 0x0, 0x0)
    /var/folders/f6/l26tk3xs5pjczcd5k5pcrmk00000gn/T/go-fuzz-build846495901/src/github.com/hashicorp/hcl/hcl/parser/parser.go:196 +0x122
github.com/hashicorp/hcl/hcl/parser.(*Parser).objectItem(0xc820041c88, 0x0, 0x0, 0x0)
    /var/folders/f6/l26tk3xs5pjczcd5k5pcrmk00000gn/T/go-fuzz-build846495901/src/github.com/hashicorp/hcl/hcl/parser/parser.go:125 +0xd5
github.com/hashicorp/hcl/hcl/parser.(*Parser).objectList(0xc820041c88, 0x0, 0x0, 0x0)
    /var/folders/f6/l26tk3xs5pjczcd5k5pcrmk00000gn/T/go-fuzz-build846495901/src/github.com/hashicorp/hcl/hcl/parser/parser.go:70 +0x127
github.com/hashicorp/hcl/hcl/parser.(*Parser).Parse(0xc820041c88, 0xc820072d00, 0x0, 0x0)
    /var/folders/f6/l26tk3xs5pjczcd5k5pcrmk00000gn/T/go-fuzz-build846495901/src/github.com/hashicorp/hcl/hcl/parser/parser.go:53 +0x166
github.com/hashicorp/hcl/hcl/parser.Parse(0x3d3000, 0x11, 0x200000, 0x1, 0x0, 0x0)
    /var/folders/f6/l26tk3xs5pjczcd5k5pcrmk00000gn/T/go-fuzz-build846495901/src/github.com/hashicorp/hcl/hcl/parser/parser.go:40 +0x24d
github.com/hashicorp/hcl.parse(0x3d3000, 0x11, 0x200000, 0x0, 0x0, 0x0)
    /var/folders/f6/l26tk3xs5pjczcd5k5pcrmk00000gn/T/go-fuzz-build846495901/src/github.com/hashicorp/hcl/parse.go:26 +0xc3
github.com/hashicorp/hcl.Unmarshal(0x3d3000, 0x11, 0x200000, 0x18d2e0, 0xc82000a340, 0x0, 0x0)
    /var/folders/f6/l26tk3xs5pjczcd5k5pcrmk00000gn/T/go-fuzz-build846495901/src/github.com/hashicorp/hcl/decoder.go:27 +0x7e
github.com/BrianHicks/fuzz-hcl.ParseSafely(0x3d3000, 0x11, 0x200000, 0x0, 0x0, 0x0, 0x0)
    /var/folders/f6/l26tk3xs5pjczcd5k5pcrmk00000gn/T/go-fuzz-build846495901/src/github.com/BrianHicks/fuzz-hcl/fuzz.go:20 +0xc1
github.com/BrianHicks/fuzz-hcl.Fuzz(0x3d3000, 0x11, 0x200000, 0xc820070058)
    /var/folders/f6/l26tk3xs5pjczcd5k5pcrmk00000gn/T/go-fuzz-build846495901/src/github.com/BrianHicks/fuzz-hcl/fuzz.go:11 +0x105
go-fuzz-dep.Main(0x23a3e8)
    /var/folders/f6/l26tk3xs5pjczcd5k5pcrmk00000gn/T/go-fuzz-build846495901/src/go-fuzz-dep/main.go:49 +0x14c
main.main()
    /var/folders/f6/l26tk3xs5pjczcd5k5pcrmk00000gn/T/go-fuzz-build846495901/src/go.fuzz.main/main.go:10 +0x23
exit status 2

(and here it is when run through panicparse, for convenience)

illegal
panic: regexp: Compile("[[:space:]]*\xdc<<070005\\z"): error parsing regexp: invalid UTF-8: `‹<<070005\z`

exit status 2
To see all goroutines, visit https://github.com/maruel/panicparse#GOTRACEBACK

1: running
                panic.go:481   panic(0x19b960, 0xc82000a420)
    regexp      regexp.go:232  MustCompile(0xc8200102c0, 0x17, 0xc820041618)
    scanner     scanner.go:433 (*Scanner).scanHeredoc(#2)
    scanner     scanner.go:180 (*Scanner).Scan(#2, 0, 0, 0, 0, 0, 0, 0, 0, 0)
    parser      parser.go:376  (*Parser).scan(#1, 0, 0, 0, 0, 0, 0, 0, 0, 0)
    parser      parser.go:196  (*Parser).objectKey(#1, 0, 0, 0, 0, 0)
    parser      parser.go:125  (*Parser).objectItem(#1, 0, 0, 0)
    parser      parser.go:70   (*Parser).objectList(#1, 0, 0, 0)
    parser      parser.go:53   (*Parser).Parse(#1, #2, 0, 0)
    parser      parser.go:40   Parse(0x3d3000, 0x11, 0x200000, 0x1, 0, 0)
    hcl         parse.go:26    parse(0x3d3000, 0x11, 0x200000, 0, 0, 0)
    hcl         decoder.go:27  Unmarshal(0x3d3000, 0x11, 0x200000, 0x18d2e0, 0xc82000a340, 0, 0)
    fuzz-hcl    fuzz.go:20     ParseSafely(0x3d3000, 0x11, 0x200000, 0, 0, 0, 0)
    fuzz-hcl    fuzz.go:11     Fuzz(0x3d3000, 0x11, 0x200000, 0xc820070058)
    go-fuzz-dep main.go:49     Main(0x23a3e8)
    main        main.go:10     main()

Other inputs that create this same panic: https://gist.github.com/d092170934be43ecfd4af02ebe61d5ad