Bad hack to silence UBSan nullptr-with-offset

...since e912a446210fdae61be3fc04d20d90488cedcdf6 "tiff: use more complicated
apis to need a smaller buffer during read" in CppunitTest_vcl_filters_test,

> [_RUN_____] TiffFilterTest::testCVEs
[...]
> tif_getimage.c:998:21: runtime error: applying zero offset to null pointer
>     #0 0x7f487da9d408 in gtStripContig /workdir/UnpackedTarball/libtiff/libtiff/tif_getimage.c:998:21
>     #1 0x7f487da97c27 in TIFFRGBAImageGet /workdir/UnpackedTarball/libtiff/libtiff/tif_getimage.c:512:12
>     #2 0x7f487bd1a56c in ImportTiffGraphicImport(SvStream&, Graphic&) /vcl/source/filter/itiff/itiff.cxx:219:19
>     #3 0x7f485d820126 in TiffFilterTest::load(rtl::OUString const&, rtl::OUString const&, rtl::OUString const&, SfxFilterFlags, SotClipboardFormatId, unsigned int) /vcl/qa/cppunit/graphicfilter/filters-tiff-test.cxx:70:12
>     #4 0x7f485a49ffa0 in test::FiltersTest::recursiveScan(test::filterStatus, rtl::OUString const&, rtl::OUString const&, rtl::OUString const&, SfxFilterFlags, SotClipboardFormatId, unsigned int, bool) /unotest/source/cpp/filters-test.cxx:132:20
>     #5 0x7f485a4a3a52 in test::FiltersTest::testDir(rtl::OUString const&, std::basic_string_view<char16_t, std::char_traits<char16_t> >, rtl::OUString const&, SfxFilterFlags, SotClipboardFormatId, unsigned int, bool) /unotest/source/cpp/filters-test.cxx:157:5
>     #6 0x7f485d8206f9 in TiffFilterTest::testCVEs() /vcl/qa/cppunit/graphicfilter/filters-tiff-test.cxx:76:5

(<https://ci.libreoffice.org/job/lo_ubsan/2406/>).

(If UBSan or some other tool starts to flag this too, we'll probably need to
pass in a nullptr after all and teach libtiff to treat that case specially and
not advance it.)

Change-Id: I4477e6c7036c3c5f2782c2c90c612d98fee60468
Reviewed-on: https://gerrit.libreoffice.org/c/core/+/134822
Tested-by: Jenkins
Reviewed-by: Caolán McNamara <caolanm@redhat.com>

0 files changed, 0 insertions, 0 deletions