Crash with gnome#627420-1.ods in string related function

[Markus Mohrhard]

2013/1/3 Lubos Lunak <l.lunak at suse.cz>:
> On Thursday 03 of January 2013, Markus Mohrhard wrote:
>> Hey,
>>
>> while going through the list of calc documents crashing during import
>> I came across gnome#627420-1.ods which creates an insanely large
>> OUStringBuffer that ultimately leads to a crash. Since I believe we
>> have quite a few places contain such problems. I wanted to ask if we
>> should not try to find a solution in the string classes instead of
>> having crashs with such documents from time to time.
>
>  The question is, what kind of solution do you expect? Presumably the crash
> was because the allocation failed and the assert was a no-op because of
> non-debug build, leading to NULL pointer dereference. So probably the only
> thing we can do is have the assert always active, changing the crash to a
> different kind of crash, but that seems to be about it.
>

Just to cear somethings up. I do have a dbgutil/debug build and it did
not return a null pointer. It returned a pointer to some invalid
memory which later results in the crash. Please also note that the
document is perfectly fine and valid according to ODF and my "fix" for
it is for example now only a random limit for the text length.

I have no idea how to find a general solution but I know that it would
be good to have a way to prevent crashes with these documents. It
sounds much better to find a way to prevent the crash in these
documents on the string implementation than hope to find all places in
our import code. While it might be a good idea to fix the import and
check the input we will always have new import code where we forget to
add these additional dafety checks. A string that is several ten
million characters long is a good indicator for a potential problem.

Regards,
Markus