A NULL pointer dereference in the function hash() modules/preprocs/nasm/nasm-pp.c:1114

[Clingto]

System info:
Ubuntu 16.04.6 LTS, X64, gcc 5.4.0, yasm (latest master 009450c)
Compile Command:

$ ./autogen.sh
make distclean

CC=gcc CXX=g++ CFLAGS="-fsanitize=address -fno-omit-frame-pointer -g" CXXFLAGS="-fsanitize=address -fno-omit-frame-pointer -g" ./configure --prefix=$PWD/build --disable-shared
make -j
make install

Run Command:

$ yasm  $POC

POC file:
https://github.com/Clingto/POC/blob/master/MSA/yasm/yasm-1114-hash-null-pointer-deref

ASAN info:

yasm: file name already has no extension: output will be in `yasm.out'
ASAN:SIGSEGV
=================================================================
==11392==ERROR: AddressSanitizer: SEGV on unknown address 0x000000000000 (pc 0x7f3f936ac15c bp 0x7ffc98fb57a0 sp 0x7ffc98fb5760 T0)
    #0 0x7f3f936ac15b in hash  test/yasm-uaf/SRC_asan/modules/preprocs/nasm/nasm-pp.c:1114
    #1 0x7f3f936b5ab9 in do_directive  test/yasm-uaf/SRC_asan/modules/preprocs/nasm/nasm-pp.c:3103
    #2 0x7f3f936c0333 in pp_getline  test/yasm-uaf/SRC_asan/modules/preprocs/nasm/nasm-pp.c:5083
    #3 0x7f3f936a9d46 in nasm_preproc_get_line  test/yasm-uaf/SRC_asan/modules/preprocs/nasm/nasm-preproc.c:198
    #4 0x7f3f9369b2ac in nasm_parser_parse  test/yasm-uaf/SRC_asan/modules/parsers/nasm/nasm-parse.c:218
    #5 0x7f3f9368f36b in nasm_do_parse  test/yasm-uaf/SRC_asan/modules/parsers/nasm/nasm-parser.c:66
    #6 0x7f3f9368f36b in nasm_parser_do_parse  test/yasm-uaf/SRC_asan/modules/parsers/nasm/nasm-parser.c:83
    #7 0x402c84 in do_assemble  test/yasm-uaf/SRC_asan/frontends/yasm/yasm.c:521
    #8 0x402c84 in main  test/yasm-uaf/SRC_asan/frontends/yasm/yasm.c:753
    #9 0x7f3f967b582f in __libc_start_main (/lib/x86_64-linux-gnu/libc.so.6+0x2082f)
    #10 0x403ee8 in _start ( test/yasm-uaf/bin_asan/bin/yasm+0x403ee8)

AddressSanitizer can not provide additional info.
SUMMARY: AddressSanitizer: SEGV  test/yasm-uaf/SRC_asan/modules/preprocs/nasm/nasm-pp.c:1114 hash
==11392==ABORTING

[rathann]

This is CVE-2021-33456 .