This confuses valgrind. I submitted a pull request upstream: https://github.com/besser82/libxcrypt/pull/21 We also need this in Fedora 28.
libxcrypt-4.1.1-1.fc28 has been submitted as an update to Fedora 28. https://bodhi.fedoraproject.org/updates/FEDORA-2018-41093fcfb6
libxcrypt-4.1.1-1.fc28 has been pushed to the Fedora 28 testing repository. If problems still persist, please make note of it in this bug report. See https://fedoraproject.org/wiki/QA:Updates_Testing for instructions on how to install test updates. You can provide feedback for this update here: https://bodhi.fedoraproject.org/updates/FEDORA-2018-41093fcfb6
libxcrypt-4.1.1-1.fc28 has been pushed to the Fedora 28 stable repository. If problems still persist, please make note of it in this bug report.