From 78004e9a87f240df03e2f73120d291763c32e0a7 Mon Sep 17 00:00:00 2001 From: Ali Ahmet Memis Date: Fri, 21 Aug 2026 01:45:27 +0000 Subject: openrisc: fix arbitrary kernel memory access via or1k_atomic syscall sys_or1k_atomic() (syscall 244 in the "or1k" ABI) takes two user pointers, v1 and v2, and swaps the words they point to in hand-written assembly. l.lwz r29,0(r4) l.lwz r27,0(r5) l.sw 0(r4),r27 l.sw 0(r5),r29 The pointers are not checked with access_ok(). The four memory accesses also have no exception table entries. A caller passes a kernel address as either pointer, and the syscall reads from and writes to it directly. This gives an unprivileged process a kernel read/write primitive. It overwrites kernel data such as the sys_call_table, gaining code execution in kernel context. Check both pointers before entering the critical section. Add fixups for the four memory accesses so faults on valid but unmapped user addresses return -EFAULT. [shorne@gmail.com: fix comment style] Fixes: 9d02a4283e9c ("OpenRISC: Boot code") Cc: stable@vger.kernel.org Signed-off-by: Ali Ahmet Memis Signed-off-by: Stafford Horne --- Documentation/ABI/testing/debugfs-vfio | 57 ++++++++++++++++++++++++++++++++++ 1 file changed, 57 insertions(+) create mode 100644 Documentation/ABI/testing/debugfs-vfio (limited to 'Documentation/ABI/testing/debugfs-vfio') diff --git a/Documentation/ABI/testing/debugfs-vfio b/Documentation/ABI/testing/debugfs-vfio new file mode 100644 index 000000000..ed2f29c3a --- /dev/null +++ b/Documentation/ABI/testing/debugfs-vfio @@ -0,0 +1,57 @@ +What: /sys/kernel/debug/vfio +Date: December 2023 +KernelVersion: 6.8 +Contact: Longfang Liu +Description: This debugfs file directory is used for debugging + of vfio devices, it's a common directory for all vfio devices. + Vfio core will create a device subdirectory under this + directory. + +What: /sys/kernel/debug/vfio//migration +Date: December 2023 +KernelVersion: 6.8 +Contact: Longfang Liu +Description: This debugfs file directory is used for debugging + of vfio devices that support live migration. + The debugfs of each vfio device that supports live migration + could be created under this directory. + +What: /sys/kernel/debug/vfio//migration/state +Date: December 2023 +KernelVersion: 6.8 +Contact: Longfang Liu +Description: Read the live migration status of the vfio device. + The contents of the state file reflects the migration state + relative to those defined in the vfio_device_mig_state enum + +What: /sys/kernel/debug/vfio//migration/features +Date: Oct 2025 +KernelVersion: 6.18 +Contact: Cédric Le Goater +Description: Read the migration features of the vfio device. + +What: /sys/kernel/debug/vfio//pci +Date: June 2026 +KernelVersion: 7.2 +Contact: Alex Williamson +Description: This debugfs file directory is used for debugging + VFIO PCI devices. + +What: /sys/kernel/debug/vfio//pci/nointxmask +Date: June 2026 +KernelVersion: 7.2 +Contact: Alex Williamson +Description: Read the nointxmask policy latched for this device. This + policy governs whether the device may use PCI 2.3 style + INTx masking when supported, reporting a value of "N", or + requires APIC level INTx masking, reporting a value of "Y". + +What: /sys/kernel/debug/vfio//pci/disable_idle_d3 +Date: June 2026 +KernelVersion: 7.2 +Contact: Alex Williamson +Description: Read the disable_idle_d3 policy latched for this device. This + policy governs whether the device PM runtime usage count is + kept elevated while the device is bound to the driver and + unused, reporting a value of "Y", or decremented to allow the + device to enter a low power state, reporting a value of "N". -- cgit v1.3.1