Let rtl_[u]stringbuffer_insert throw std::bad_alloc on overflow

Prior to a95c585433246813096e8890b7ed6ef4fe30c621 "Pump XInputStream into an
SvMemoryStream rather than an OStringBuffer", this change would have caused

> $ truncate -s 3G test.xml
> $ instdir/program/soffice test.xml

to open an effectively empty draw document (after apparently catching the
std::bad_alloc now thrown from within OrcusFormatDetect::detect; see that
commit's commit message for details) rather than crashing.  This works because
rtl_[u]stringbuffer_insert happen not to be decorated with SAL_THROW_EXTERN_C().
But even if they were (or when they are called from an external C program), it
wouldn't be worse to let the process terminate due to the unexpected C++
std::bad_alloc exception than to let it crash due to an overflown signed integer
computation and out-of-bounds memory write.

Change-Id: I21e353367e2b978e8893a2886ac875367a75abd9
Reviewed-on: https://gerrit.libreoffice.org/c/core/+/136352
Tested-by: Jenkins
Reviewed-by: Stephan Bergmann <sbergman@redhat.com>

0 files changed, 0 insertions, 0 deletions