#6 heap overflow / off by one read with malformed arc file

[Hanno Böck]

Attached file will cause a read heap overflow in arc. Test with arc -t [file]. It will usually just segfault, with valgrind or address sanitizer one can see details.

This is the relevant part of the address sanitizer stack trace:
==20169==ERROR: AddressSanitizer: heap-buffer-overflow on address 0x62d0000083fe at pc 0x42ee98 bp 0x7fff87e23b50 sp 0x7fff87e23b40
READ of size 1 at 0x62d0000083fe thread T0
#0 0x42ee97 in putb_ncr /f/arc-5.21p/arcunp.c:220
#1 0x42f5d0 in unpack /f/arc-5.21p/arcunp.c:88
#2 0x42d8bd in tstarc /f/arc-5.21p/arctst.c:43
#3 0x404f7a in main /f/arc-5.21p/arc.c:413
#4 0x7f98f1ee9f9f in __libc_start_main (/lib64/libc.so.6+0x1ff9f)
#5 0x406b2a (/f/arc-5.21p/arc+0x406b2a)

(I'll attach the full output)