[patch] Fix BZ 23400 -- stdlib/test-bz22786.c creates temporary files in glibc source tree

[Stefan Liebler]

Hi Paul,

If I run the test on s390 (31bit), the test fails with:
malloc: unable to allocate 2147483675 bytes: Cannot allocate memory
warning: could not remove temporary file: /tmp/bz22786.iaoLYS: Directory 
not empty

This test tries to allocate a little bit too much bytes for 31bit. Thus 
the former implementation returned EXIT_UNSUPPORTED. Now the test is 
failing due to xmalloc.

As the symlink was created within the temporary directory 
/tmp/bz22786.XXXXXX, but was not unlinked by the test, 
support_delete_temp_files() fails to remove it.

Can we just return EXIT_UNSUPPORTED on 31bit as done with the attached 
patch?

Bye
Stefan

On 08/06/2018 05:12 PM, Paul Pluzhnikov wrote:
> Thanks for review!
> 
> On Mon, Jul 30, 2018 at 1:13 PM Adhemerval Zanella
> <adhemerval.zanella@linaro.org> wrote:
> 
>>> +  strcpy (lnk, dir);
>>> +  strcat (lnk, "/symlink");
>>
>> Maybe just 'char *lnk = xasprintf ("%s/symlink", dir);' instead?
> 
> Done.
> 
>>> +  if (symlink (".", lnk) != 0)
>>>       {
>>>         printf ("symlink (%s, %s): %m\n", dir, lnk);
>>>         return EXIT_FAILURE;
>>
>> Use FAIL_EXIT1 or just TEST_VERIFY_EXIT.
> 
> Done.
> 
>>>     memset (p, 'a', path_len - (path - p) - 2);
>>>     p[path_len - (path - p) - 1] = '\0';
>>
>> Shouldn't it 'p - path' instead? The subtraction is clearly issuing a
>> overflow and I think it is not what the test meant here.
> 
> Good catch. Turns out that this was a buffer overflow in the original
> test. Fixed.
> 
> Thanks,
> 
> 2018-08-06  Paul Pluzhnikov  <ppluzhnikov@google.com>
> 
>          [BZ #23400]
>          * stdlib/test-bz22786.c (do_test): Fix undefined behavior.
> 

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