https://gcc.gnu.org/bugzilla/show_bug.cgi?id=99479
--- Comment #22 from CVS Commits <cvs-commit at gcc dot gnu.org> --- The master branch has been updated by Patrick Palka <ppa...@gcc.gnu.org>: https://gcc.gnu.org/g:7e7a96f774ed892e5cef53fcb68297cd0d513820 commit r12-8051-g7e7a96f774ed892e5cef53fcb68297cd0d513820 Author: Patrick Palka <ppa...@redhat.com> Date: Thu Apr 7 16:09:52 2022 -0400 c++: use after free during name lookup w/ modules [PR99479] name_lookup::search_unqualified uses a statically allocated vector in order to avoid repeated reallocation, under the assumption that the function can't be called recursively. With modules however, this assumption turns out to be false, and search_unqualified can be called recursively as demonstrated by the testcase in comment #19 of PR99479[1] where the recursive call causes the vector to get reallocated which invalidates the reference to queue[ix] held by the parent call. This patch makes search_unqualified instead use an auto_vec with 16 elements of internal storage. In turn we can simplify the API of some member functions to take the vector by reference and return void. [1]: https://gcc.gnu.org/PR99479#c19 PR c++/99479 gcc/cp/ChangeLog: * name-lookup.cc (name_lookup::using_queue): Change to an auto_vec (with 16 elements of internal storage). (name_lookup::queue_namespace): Change return type to void, take queue parameter by reference and adjust function body accordingly. (name_lookup::do_queue_usings): Inline into ... (name_lookup::queue_usings): ... here. As in queue_namespace. (name_lookup::search_unqualified): Don't make queue static, remove length variable, and adjust function body accordingly.
