In the Linux kernel, the following vulnerability has been resolved:
s390/mm: Add missing secure storage access fixups for donated memory
There are special cases where secure storage access exceptions happen
in a kernel context for pages that don't have the PG_arch_1 bit
set. That bit is set for non-exported guest secure storage (memory)
but is absent on storage donated to the Ultravisor since the kernel
isn't allowed to export donated pages.
Prior to this patch we would try to export the page by calling
arch_make_folio_accessible() which would instantly return since the
arch bit is absent signifying that the page was already exported and
no further action is necessary. This leads to secure storage access
exception loops which can never be resolved.
With this patch we unconditionally try to export and if that fails we
fixup.
A Linux kernel vulnerability on s390 architecture allows secure storage access exception loops when handling donated memory pages lacking the PG_arch_1 bit. The fix ensures unconditional export attempts with proper fixup handling to prevent infinite exception loops.
تؤثر هذه الثغرة على نواة Linux في معمارية s390 حيث تحدث استثناءات وصول التخزين الآمن في سياق kernel لصفحات الذاكرة المتبرع بها للـ Ultravisor. المشكلة تحدث لأن الكود السابق كان يحاول تصدير الصفحات بناءً على وجود بت PG_arch_1 الذي لا يكون موجوداً في الذاكرة المتبرع بها، مما يؤدي إلى حلقات استثناء لا نهائية.
A Linux kernel vulnerability on s390 architecture allows secure storage access exception loops when handling donated memory pages lacking the PG_arch_1 bit. The fix ensures unconditional export attempts with proper fixup handling to prevent infinite exception loops.
Update Linux kernel to patched version that implements unconditional secure storage export attempts with proper fixup handling for donated memory pages. Apply security patches from your Linux distribution vendor immediately.
قم بتحديث نواة Linux إلى الإصدار المصحح الذي ينفذ محاولات تصدير التخزين الآمن غير المشروط مع معالجة الإصلاح المناسبة لصفحات الذاكرة المتبرع بها. طبق تصحيحات الأمان من موفر توزيعة Linux الخاص بك فوراً.