Crash in Nasm 3.01

[kittener]

Environment

Tool(s): nasm
Version: 3.01

Platform: Linux version 5.4.0-200-generic (buildd@lcy02-amd64-023) (gcc version 9.4.0 (Ubuntu 9.4.0-1ubuntu1~20.04.2))

Build details (if relevant):

Built from: gcc

Compiler options: -g -fsanitize=address -fno-omit-frame-pointer

Detailed Reports

Memory Leak in gmem.cc
Tool: nasm

Command line to reproduce:

nasm -M -MD /tmp/output.d -o /tmp/output.o crash_nasm
Input file: crash_nasm

Observed behavior:

AddressSanitizer:DEADLYSIGNAL

==2029897==ERROR: AddressSanitizer: SEGV on unknown address 0x000000000000 (pc 0x5604db566bf6 bp 0x7ffeccf79fe0 sp 0x7ffeccf79fc0 T0)
==2029897==The signal is caused by a READ memory access.
==2029897==Hint: address points to the zero page.
#0 0x5604db566bf5 in free_Token ../asm/preproc.c:2013
#1 0x5604db566c5c in do_delete_Token ../asm/preproc.c:2028
#2 0x5604db573b34 in do_directive ../asm/preproc.c:4721
#3 0x5604db58a06f in pp_tokline ../asm/preproc.c:8748
#4 0x5604db58a5ce in pp_getline ../asm/preproc.c:8803
#5 0x5604db5313c4 in main ../asm/nasm.c:591
#6 0x7fc61bf5e082 in __libc_start_main ../csu/libc-start.c:308
#7 0x5604db52ed4d in _start (/dev_sdb/xky/opfuzz/vaild_bug/nasm-3.01/build/nasm+0x174d4d)

AddressSanitizer can not provide additional info.
SUMMARY: AddressSanitizer: SEGV ../asm/preproc.c:2013 in free_Token
==2029897==ABORTING

By
Kaiyu xie,
Institute of Information Engineering，Chinese Academy of Sciences

[maciejwieczorretman]

Hello and thanks for reporting the issue, could you post the faulting code in plain text here? The one in your link is oddly mangled and unreadable when I download it

[kittener]

The file that causes NASM to crash is a mutation created by the fuzzing tool, so it's normal that it's unreadable.