#78 stack-buffer-overflow in genptk_text at genptk.c:618

[Suhwan Song]

Hi,
I found a stack-buffer-overflow in genptk_text at genptk.c:618

fig2dev Version 3.2.7b
commit 93795dd396730c80e63767dede7777f4cb7dc383

Please run following command to reproduce it,

fig2dev -L ptk $PoC

ASAN LOG

==45827==ERROR: AddressSanitizer: stack-buffer-overflow on address 0x7fff76457e80 at pc 0x000000841291 bp 0x7fff76457650 sp 0x7fff76457648
WRITE of size 1 at 0x7fff76457e80 thread T0
    #0 0x841290 in genptk_text /home/tmp/mcj-fig2dev/fig2dev/dev/genptk.c:618:13
    #1 0x54ba7b in gendev_objects /home/tmp/mcj-fig2dev/fig2dev/fig2dev.c:1012:6
    #2 0x54ba7b in main /home/tmp/mcj-fig2dev/fig2dev/fig2dev.c:489
    #3 0x7f8360406b96 in __libc_start_main /build/glibc-OTsEL5/glibc-2.27/csu/../csu/libc-start.c:310
    #4 0x41b429 in _start (/home/tmp/fig2dev+0x41b429)

Address 0x7fff76457e80 is located in stack of thread T0 at offset 2080 in frame
    #0 0x83e5ef in genptk_text /home/tmp/mcj-fig2dev/fig2dev/dev/genptk.c:520

  This frame has 1 object(s):
    [32, 2080) 'stfp' (line 521) <== Memory access at offset 2080 overflows this variable
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-buffer-overflow /home/tmp/mcj-fig2dev/fig2dev/dev/genptk.c:618:13 in genptk_text
Shadow bytes around the buggy address:
  0x10006ec82f80: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00
  0x10006ec82f90: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00
  0x10006ec82fa0: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00
  0x10006ec82fb0: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00
  0x10006ec82fc0: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00
=>0x10006ec82fd0:[f3]f3 f3 f3 f3 f3 f3 f3 f3 f3 f3 f3 f3 f3 f3 f3
  0x10006ec82fe0: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00
  0x10006ec82ff0: 00 00 00 00 f1 f1 f1 f1 00 00 00 00 00 00 00 00
  0x10006ec83000: 00 00 f3 f3 f3 f3 f3 f3 00 00 00 00 00 00 00 00
  0x10006ec83010: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00
  0x10006ec83020: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00
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
==45827==ABORTING

[tkl]

Fixed with commit [41b9bb].