panic: sandbox escaping file name "../file0"

goroutine 16 [running]:
github.com/google/syzkaller/prog.(*randGen).filename(0xc000759260, 0xc000544ac0, 0xbf4ec0, 0x498aee, 0xc000656780)
	/syzkaller/gopath/src/github.com/google/syzkaller/prog/rand.go:161 +0x2ac
github.com/google/syzkaller/prog.(*BufferType).generate(0xbf4ec0, 0xc000759260, 0xc000544ac0, 0xc000079500, 0x1a5889a35249a32, 0xc0008ef960, 0x4f0c53, 0xc00092fce0)
	/syzkaller/gopath/src/github.com/google/syzkaller/prog/rand.go:646 +0x4fc
github.com/google/syzkaller/prog.(*randGen).generateArgImpl(0xc000759260, 0xc000544ac0, 0x8fd600, 0xbf4ec0, 0x200, 0x0, 0x0, 0x0, 0x0, 0x0)
	/syzkaller/gopath/src/github.com/google/syzkaller/prog/rand.go:581 +0x1b6
github.com/google/syzkaller/prog.(*randGen).generateArg(0xc000759260, 0xc000544ac0, 0x8fd600, 0xbf4ec0, 0xaaaaaaaaaaaaaaaa, 0x38, 0x7437b2, 0x87a299, 0x3)
	/syzkaller/gopath/src/github.com/google/syzkaller/prog/rand.go:530 +0x52
github.com/google/syzkaller/prog.(*PtrType).generate(0xbd1b40, 0xc000759260, 0xc000544ac0, 0x40b7ff, 0xc0007594a0, 0x20, 0x20, 0x8115a0)
	/syzkaller/gopath/src/github.com/google/syzkaller/prog/rand.go:729 +0x84
github.com/google/syzkaller/prog.(*randGen).generateArgImpl(0xc000759260, 0xc000544ac0, 0x8fda60, 0xbd1b40, 0xc0008efb00, 0x0, 0x0, 0x0, 0x0, 0x0)
	/syzkaller/gopath/src/github.com/google/syzkaller/prog/rand.go:581 +0x1b6
github.com/google/syzkaller/prog.(*randGen).generateArg(0xc000759260, 0xc000544ac0, 0x8fda60, 0xbd1b40, 0x2, 0x2, 0x0, 0x203000, 0xc0008efc60)
	/syzkaller/gopath/src/github.com/google/syzkaller/prog/rand.go:530 +0x52
github.com/google/syzkaller/prog.(*randGen).generateArgs(0xc000759260, 0xc000544ac0, 0xbc6840, 0x2, 0x2, 0x14276daeea19286e, 0xc0008efd28, 0x72beae, 0x7f3580, 0xc00092f110, ...)
	/syzkaller/gopath/src/github.com/google/syzkaller/prog/rand.go:518 +0x11d
github.com/google/syzkaller/prog.(*randGen).generateParticularCall(0xc000759260, 0xc000544ac0, 0xbdd420, 0x6d, 0xc000544ac0, 0xc00090ac60)
	/syzkaller/gopath/src/github.com/google/syzkaller/prog/rand.go:462 +0xd1
github.com/google/syzkaller/prog.(*randGen).generateCall(0xc000759260, 0xc000544ac0, 0xc00043f4c0, 0xc000544ac0, 0xc0008efdc0, 0x7311e7)
	/syzkaller/gopath/src/github.com/google/syzkaller/prog/rand.go:454 +0xa4
github.com/google/syzkaller/prog.(*mutator).insertCall(0xc0008efe48, 0x14)
	/syzkaller/gopath/src/github.com/google/syzkaller/prog/mutation.go:118 +0xcb
github.com/google/syzkaller/prog.(*Prog).Mutate(0xc00043f4c0, 0x8f8660, 0xc00092fce0, 0x1e, 0xc0006b8680, 0xc000790000, 0x8f6, 0x900)
	/syzkaller/gopath/src/github.com/google/syzkaller/prog/mutation.go:32 +0x299
main.(*Proc).smashInput(0xc0006b86c0, 0xc000a8cb40)
	/syzkaller/gopath/src/github.com/google/syzkaller/syz-fuzzer/proc.go:196 +0x103
main.(*Proc).loop(0xc0006b86c0)
	/syzkaller/gopath/src/github.com/google/syzkaller/syz-fuzzer/proc.go:82 +0x177created by main.main
	/syzkaller/gopath/src/github.com/google/syzkaller/syz-fuzzer/fuzzer.go:236 +0xfe2


OpenBSD/amd64 (worker.syzkaller) (tty00)

login: set $lines = 0
Password:
Login incorrect
login: trace
Password:
Login incorrect
login: show proc
Password:
Login incorrect