CVE-2025-38257

In the Linux kernel, the following vulnerability has been resolved:<br /> <br /> s390/pkey: Prevent overflow in size calculation for memdup_user()<br /> <br /> Number of apqn target list entries contained in &amp;#39;nr_apqns&amp;#39; variable is<br /> determined by userspace via an ioctl call so the result of the product in<br /> calculation of size passed to memdup_user() may overflow.<br /> <br /> In this case the actual size of the allocated area and the value<br /> describing it won&amp;#39;t be in sync leading to various types of unpredictable<br /> behaviour later.<br /> <br /> Use a proper memdup_array_user() helper which returns an error if an<br /> overflow is detected. Note that it is different from when nr_apqns is<br /> initially zero - that case is considered valid and should be handled in<br /> subsequent pkey_handler implementations.<br /> <br /> Found by Linux Verification Center (linuxtesting.org).