office-gobmx/external/mdds/use-after-free.patch
Stephan Bergmann a6f21bc32e external/mdds: Avoid -Werror=use-after-free (GCC 12 trunk)
> In file included from workdir/UnpackedTarball/mdds/include/mdds/flat_segment_tree.hpp:37,
>                  from sc/inc/columnspanset.hxx:16,
>                  from sc/source/core/data/columnspanset.cxx:10:
> In function ‘void mdds::__st::intrusive_ptr_add_ref(node<T>*) [with T = mdds::flat_segment_tree<int, bool>]’,
>     inlined from ‘boost::intrusive_ptr<T>::intrusive_ptr(const boost::intrusive_ptr<T>&) [with T = mdds::__st::node<mdds::flat_segment_tree<int, bool> >]’ at workdir/UnpackedTarball/boost/boost/smart_ptr/intrusive_ptr.hpp:93:44,
>     inlined from ‘boost::intrusive_ptr<T>& boost::intrusive_ptr<T>::operator=(const boost::intrusive_ptr<T>&) [with T = mdds::__st::node<mdds::flat_segment_tree<int, bool> >]’ at workdir/UnpackedTarball/boost/boost/smart_ptr/intrusive_ptr.hpp:154:9,
>     inlined from ‘mdds::flat_segment_tree<_Key, _Value>::flat_segment_tree(const mdds::flat_segment_tree<_Key, _Value>&) [with _Key = int; _Value = bool]’ at workdir/UnpackedTarball/mdds/include/mdds/flat_segment_tree_def.inl:88:25:
> workdir/UnpackedTarball/mdds/include/mdds/node.hpp:244:10: error: pointer used after ‘void operator delete(void*, std::size_t)’ [-Werror=use-after-free]
>   244 |     ++p->refcount;
>       |       ~~~^~~~~~~~
> In function ‘void mdds::__st::intrusive_ptr_release(node<T>*) [with T = mdds::flat_segment_tree<int, bool>]’,
>     inlined from ‘void mdds::__st::intrusive_ptr_release(node<T>*) [with T = mdds::flat_segment_tree<int, bool>]’ at workdir/UnpackedTarball/mdds/include/mdds/node.hpp:248:13,
>     inlined from ‘boost::intrusive_ptr<T>::~intrusive_ptr() [with T = mdds::__st::node<mdds::flat_segment_tree<int, bool> >]’ at workdir/UnpackedTarball/boost/boost/smart_ptr/intrusive_ptr.hpp:98:44,
>     inlined from ‘boost::intrusive_ptr<T>& boost::intrusive_ptr<T>::operator=(const boost::intrusive_ptr<T>&) [with T = mdds::__st::node<mdds::flat_segment_tree<int, bool> >]’ at workdir/UnpackedTarball/boost/boost/smart_ptr/intrusive_ptr.hpp:154:9,
>     inlined from ‘mdds::flat_segment_tree<_Key, _Value>::flat_segment_tree(const mdds::flat_segment_tree<_Key, _Value>&) [with _Key = int; _Value = bool]’ at workdir/UnpackedTarball/mdds/include/mdds/flat_segment_tree_def.inl:87:19:
> workdir/UnpackedTarball/mdds/include/mdds/node.hpp:252:9: note: call to ‘void operator delete(void*, std::size_t)’ here
>   252 |         delete p;
>       |         ^~~~~~~~

etc.  The warning is apparently new in GCC 12 trunk (see
<https://gcc.gnu.org/git/?p=gcc.git;a=commit;h=671a283636de75f7ed638ee6b01ed2d44361b8b6>
"Add -Wuse-after-free [PR80532]"), and I'm not entirely sure whether this
is a true or false positive, but the fix looks somewhat plausible, and at least
also my (Clang) ASan+UBSan build does a successful `make check` with (and
without) this change.

Change-Id: I63fafceba8d1b4e0ddd7cf2e58403a3bc763e53c
Reviewed-on: https://gerrit.libreoffice.org/c/core/+/129008
Tested-by: Jenkins
Reviewed-by: Stephan Bergmann <sbergman@redhat.com>
2022-01-27 08:00:48 +01:00

12 lines
440 B
Diff

--- include/mdds/flat_segment_tree_def.inl
+++ include/mdds/flat_segment_tree_def.inl
@@ -84,8 +84,8 @@
// Move on to the next destination node, and have the next node point
// back to the previous node.
node_ptr old_node = dest_node;
+ dest_node->next->prev = old_node;
dest_node = dest_node->next;
- dest_node->prev = old_node;
if (src_node == r.m_right_leaf.get())
{