[Bug 1922646] Re: Long text crash dcigettext.c with segfault

[Gunnar Hjalmarsson]

Well, I'm not the one who would fix anything. I just jumped in since I
thought you had made a mistake. Leaving it to the glibc maintainers to
evaluate the importance of your observation.

** Changed in: glibc (Ubuntu)
       Status: Incomplete => New

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Title:
  Long text crash dcigettext.c with segfault

Status in glibc package in Ubuntu:
  New

Bug description:
  Bug description:
  Module locale of CPython interpreter use dcigettext.c. When locale.dgettext() is filled with long text, it will cause crashes.  (Short text is fine)

  
  ======================================================
  Python 3.10.0a6 (default, Mar 19 2021, 11:45:56) [GCC 7.5.0] on linux
  Type "help", "copyright", "credits" or "license" for more information.
  >>> import locale;locale.dgettext('abs'*10000000,'')
  Segmentation fault (core dumped)


  
  Testing with valgrind: 
  ======================================================
  ~$ PYTHONMALLOC=malloc_debug valgrind python
  Memcheck, a memory error detector
  ==4870== Copyright (C) 2002-2017, and GNU GPL'd, by Julian Seward et al.
  ==4870== Using Valgrind-3.16.1 and LibVEX; rerun with -h for copyright info
  ==4870== Command: /home/xxm/Desktop/apifuzz/Python-3.10.0a6/python
  ==4870== 
  Python 3.10.0a6 (default, Mar 19 2021, 11:45:56) [GCC 7.5.0] on linux
  Type "help", "copyright", "credits" or "license" for more information.
  >>> import locale
  >>> locale.dgettext('abs'*10000000,'')
  ==4870== Warning: client switching stacks?  SP change: 0x1ffefff5c0 --> 0x1ffd363220
  ==4870==          to suppress, use: --max-stackframe=30000032 or greater
  ==4870== Invalid write of size 8
  ==4870==    at 0x5797E88: __dcigettext (dcigettext.c:675)
  ==4870==  Address 0x1ffd363218 is on thread 1's stack
  ==4870== 
  ==4870== 
  ==4870== Process terminating with default action of signal 11 (SIGSEGV)
  ==4870==  Access not within mapped region at address 0x1FFD363218
  ==4870==    at 0x5797E88: __dcigettext (dcigettext.c:675)
  ==4870==  If you believe this happened as a result of a stack
  ==4870==  overflow in your program's main thread (unlikely but
  ==4870==  possible), you can try to increase the size of the
  ==4870==  main thread stack using the --main-stacksize= flag.
  ==4870==  The main thread stack size used in this run was 8388608.
  ==4870== Invalid write of size 8
  ==4870==    at 0x4A2867A: _vgnU_freeres (vg_preloaded.c:57)
  ==4870==  Address 0x1ffd363210 is on thread 1's stack
  ==4870== 
  ==4870== 
  ==4870== Process terminating with default action of signal 11 (SIGSEGV)
  ==4870==  Access not within mapped region at address 0x1FFD363210
  ==4870==    at 0x4A2867A: _vgnU_freeres (vg_preloaded.c:57)
  ==4870==  If you believe this happened as a result of a stack
  ==4870==  overflow in your program's main thread (unlikely but
  ==4870==  possible), you can try to increase the size of the
  ==4870==  main thread stack using the --main-stacksize= flag.
  ==4870==  The main thread stack size used in this run was 8388608.
  ==4870== 
  ==4870== HEAP SUMMARY:
  ==4870==     in use at exit: 35,310,749 bytes in 35,706 blocks
  ==4870==   total heap usage: 87,221 allocs, 51,515 frees, 44,733,752 bytes allocated
  ==4870== 
  ==4870== LEAK SUMMARY:
  ==4870==    definitely lost: 0 bytes in 0 blocks
  ==4870==    indirectly lost: 0 bytes in 0 blocks
  ==4870==      possibly lost: 35,173,680 bytes in 34,899 blocks
  ==4870==    still reachable: 137,069 bytes in 807 blocks
  ==4870==         suppressed: 0 bytes in 0 blocks
  ==4870== Rerun with --leak-check=full to see details of leaked memory
  ==4870== 
  ==4870== For lists of detected and suppressed errors, rerun with: -s
  ==4870== ERROR SUMMARY: 2 errors from 2 contexts (suppressed: 0 from 0)
  Segmentation fault (core dumped)


  Testing with gdb
  ======================================================
  $gdb ./python
  (gdb) run
  >>> locale.dgettext('abs'*10000000,'')

  Program received signal SIGSEGV, Segmentation fault.
  __dcigettext (
      domainname=domainname at entry=0xadb030 "absabsabsabsabsabsabsabsabsabsabsabsabsabsabsabsabsabsabsabsabsabsabsabsabsabsabsabsabsabsabsabsabsabsabsabsabsabsabsabsabsabsabsabsabsabsabsabsabsabsabsabsabsabsabsabsabsabsabsabsabsabsabsabsabsabsab"..., msgid1=msgid1 at entry=0x7ffff7fc09a0 "", msgid2=msgid2 at entry=0x0, 
      plural=plural at entry=0, n=n at entry=0, category=category at entry=5) at dcigettext.c:675
  675	dcigettext.c: No such file or directory.
  (gdb)

  ======================================================

  
  ProblemType: Crash

  $ldd --version
  Ubuntu GLIBC 2.23-0ubuntu11.2) 2.23


  $uname -a
  Linux xxm 4.15.0-64-generic #73~16.04.1-Ubunut SMP Fri Sep 13, UTC 2019 x86_64 x86_64 x86_64 GNU/Linux

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