CVE-2022-50230

In the Linux kernel, the following vulnerability has been resolved:<br /> <br /> arm64: set UXN on swapper page tables<br /> <br /> [ This issue was fixed upstream by accident in c3cee924bd85 ("arm64:<br /> head: cover entire kernel image in initial ID map") as part of a<br /> large refactoring of the arm64 boot flow. This simple fix is therefore<br /> preferred for -stable backporting ]<br /> <br /> On a system that implements FEAT_EPAN, read/write access to the idmap<br /> is denied because UXN is not set on the swapper PTEs. As a result,<br /> idmap_kpti_install_ng_mappings panics the kernel when accessing<br /> __idmap_kpti_flag. Fix it by setting UXN on these PTEs.