[Nasm-bugs] [Bug 3392643] New: stack-use-after-scope in expand_mmac_params at asm/preproc.c:4931

[noreply-nasm at dev.nasm.us]

https://bugzilla.nasm.us/show_bug.cgi?id=3392643

            Bug ID: 3392643
           Summary: stack-use-after-scope in expand_mmac_params at
                    asm/preproc.c:4931
           Product: NASM
           Version: 2.15 (development)
          Hardware: PC
                OS: Linux
            Status: OPEN
          Severity: normal
          Priority: Medium
         Component: Assembler
          Assignee: nobody at nasm.us
          Reporter: prada960808 at gmail.com
                CC: chang.seok.bae at intel.com, gorcunov at gmail.com,
                    hpa at zytor.com, nasm-bugs at nasm.us
     Obtained from: Built from git using configure

Created attachment 411754
  --> https://bugzilla.nasm.us/attachment.cgi?id=411754&action=edit
poc

Hi, 
I found a stack-use-after-scope in expand_mmac_params at asm/preproc.c:4931
It is triggered in nasm version 2.15.
Please run following command

nasm -o /dev/null -f bin $PoC

Here's ASAN LOG
==30308==ERROR: AddressSanitizer: stack-use-after-scope on address
0x7ffc324707c0 at pc 0x00000062e905 bp 0x7ffc32470790 sp 0x7ffc32470788
WRITE of size 8 at 0x7ffc324707c0 thread T0
    #0 0x62e904 in expand_mmac_params
/home/suhwan/project/program/nasm-2.15rc0-20191023/asm/preproc.c:4931:11
    #1 0x5e8123 in pp_tokline
/home/suhwan/project/program/nasm-2.15rc0-20191023/asm/preproc.c:6361:21
    #2 0x5e8123 in pp_getline
/home/suhwan/project/program/nasm-2.15rc0-20191023/asm/preproc.c:6428
    #3 0x50a7f9 in assemble_file
/home/suhwan/project/program/nasm-2.15rc0-20191023/asm/nasm.c:1630:24
    #4 0x50a7f9 in main
/home/suhwan/project/program/nasm-2.15rc0-20191023/asm/nasm.c:637
    #5 0x7f2ca11a5b96 in __libc_start_main
/build/glibc-OTsEL5/glibc-2.27/csu/../csu/libc-start.c:310
    #6 0x41a4a9 in _start
(/mnt/hda2/suhwan/BUG_AFL/ezxml_fuzzing/nasm+0x41a4a9)

Address 0x7ffc324707c0 is located in stack of thread T0 at offset 32 in frame
    #0 0x61fc6f in expand_mmac_params
/home/suhwan/project/program/nasm-2.15rc0-20191023/asm/preproc.c:4749

  This frame has 5 object(s):
    [32, 40) 'newlist.i249' (line 979) <== Memory access at offset 32 is inside
this variable
    [64, 72) 'newlist.i' (line 1002)
    [96, 104) 'thead' (line 4750)
    [128, 136) 'ep' (line 4816)
    [160, 168) 'ep36' (line 4834)
HINT: this may be a false positive if your program uses some custom stack
unwind mechanism or swapcontext
      (longjmp and C++ exceptions *are* supported)
SUMMARY: AddressSanitizer: stack-use-after-scope
/home/suhwan/project/program/nasm-2.15rc0-20191023/asm/preproc.c:4931:11 in
expand_mmac_params
Shadow bytes around the buggy address:
  0x1000064860a0: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00
  0x1000064860b0: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00
  0x1000064860c0: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00
  0x1000064860d0: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00
  0x1000064860e0: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00
=>0x1000064860f0: 00 00 00 00 f1 f1 f1 f1[f8]f2 f2 f2 f8 f2 f2 f2
  0x100006486100: 00 f2 f2 f2 f8 f2 f2 f2 f8 f3 f3 f3 00 00 00 00
  0x100006486110: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00
  0x100006486120: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00
  0x100006486130: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00
  0x100006486140: f1 f1 f1 f1 f8 f2 f2 f2 f8 f2 f2 f2 f8 f2 f2 f2
Shadow byte legend (one shadow byte represents 8 application bytes):
  Addressable:           00
  Partially addressable: 01 02 03 04 05 06 07 
  Heap left redzone:       fa
  Freed heap region:       fd
  Stack left redzone:      f1
  Stack mid redzone:       f2
  Stack right redzone:     f3
  Stack after return:      f5
  Stack use after scope:   f8
  Global redzone:          f9
  Global init order:       f6
  Poisoned by user:        f7
  Container overflow:      fc
  Array cookie:            ac
  Intra object redzone:    bb
  ASan internal:           fe
  Left alloca redzone:     ca
  Right alloca redzone:    cb
==30308==ABORTING

NASM version 2.15rc0-20191023 compiled on Dec  9 2019

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