time: panic in LoadLocationFromTZData with malformed data

[josharian]

package main

import "time"

func main() {
	tzdata := "TZif\x00000000000000000\x00\x00\x00\x01\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x0000"
	time.LoadLocationFromTZData("abc", []byte(tzdata))
}

Tip:

panic: runtime error: index out of range

goroutine 1 [running]:
time.LoadLocationFromTZData(0x1074f08, 0x3, 0xc00007c030, 0x2e, 0x30, 0x30, 0xc000072058, 0x0)
	/Users/josh/go/tip/src/time/zoneinfo_read.go:226 +0xf09
main.main()
	/Users/josh/go/tip/src/x.go:7 +0x77
exit status 2

Playground: https://play.golang.com/p/1nF0x-TpNaL

Found with go-fuzz.

cc @dvyukov

[gopherbot]

Change https://golang.org/cl/155746 mentions this issue: time: reject tzdata with no zones