CVE-2025-21713

In the Linux kernel, the following vulnerability has been resolved:<br /> <br /> powerpc/pseries/iommu: Don&amp;#39;t unset window if it was never set<br /> <br /> On pSeries, when user attempts to use the same vfio container used by<br /> different iommu group, the spapr_tce_set_window() returns -EPERM<br /> and the subsequent cleanup leads to the below crash.<br /> <br /> Kernel attempted to read user page (308) - exploit attempt?<br /> BUG: Kernel NULL pointer dereference on read at 0x00000308<br /> Faulting instruction address: 0xc0000000001ce358<br /> Oops: Kernel access of bad area, sig: 11 [#1]<br /> NIP: c0000000001ce358 LR: c0000000001ce05c CTR: c00000000005add0<br /> <br /> NIP [c0000000001ce358] spapr_tce_unset_window+0x3b8/0x510<br /> LR [c0000000001ce05c] spapr_tce_unset_window+0xbc/0x510<br /> Call Trace:<br /> spapr_tce_unset_window+0xbc/0x510 (unreliable)<br /> tce_iommu_attach_group+0x24c/0x340 [vfio_iommu_spapr_tce]<br /> vfio_container_attach_group+0xec/0x240 [vfio]<br /> vfio_group_fops_unl_ioctl+0x548/0xb00 [vfio]<br /> sys_ioctl+0x754/0x1580<br /> system_call_exception+0x13c/0x330<br /> system_call_vectored_common+0x15c/0x2ec<br /> <br /> --- interrupt: 3000<br /> <br /> Fix this by having null check for the tbl passed to the<br /> spapr_tce_unset_window().