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/sysfs-driver-uacce | 57 ++++++++++++++++++++++++++++ 1 file changed, 57 insertions(+) create mode 100644 Documentation/ABI/testing/sysfs-driver-uacce (limited to 'Documentation/ABI/testing/sysfs-driver-uacce') diff --git a/Documentation/ABI/testing/sysfs-driver-uacce b/Documentation/ABI/testing/sysfs-driver-uacce new file mode 100644 index 000000000..d3f0b8f3c --- /dev/null +++ b/Documentation/ABI/testing/sysfs-driver-uacce @@ -0,0 +1,57 @@ +What: /sys/class/uacce//api +Date: Feb 2020 +KernelVersion: 5.7 +Contact: linux-accelerators@lists.ozlabs.org +Description: Api of the device + Can be any string and up to userspace to parse. + Application use the api to match the correct driver + +What: /sys/class/uacce//flags +Date: Feb 2020 +KernelVersion: 5.7 +Contact: linux-accelerators@lists.ozlabs.org +Description: Attributes of the device, see UACCE_DEV_xxx flag defined in uacce.h + +What: /sys/class/uacce//available_instances +Date: Feb 2020 +KernelVersion: 5.7 +Contact: linux-accelerators@lists.ozlabs.org +Description: Available instances left of the device + Return -ENODEV if uacce_ops get_available_instances is not provided + +What: /sys/class/uacce//isolate_strategy +Date: Nov 2022 +KernelVersion: 6.1 +Contact: linux-accelerators@lists.ozlabs.org +Description: (RW) A sysfs node that configure the error threshold for the hardware + isolation strategy. This size is a configured integer value, which is the + number of threshold for hardware errors occurred in one hour. The default is 0. + 0 means never isolate the device. The maximum value is 65535. You can write + a number of threshold based on your hardware. + +What: /sys/class/uacce//isolate +Date: Nov 2022 +KernelVersion: 6.1 +Contact: linux-accelerators@lists.ozlabs.org +Description: (R) A sysfs node that read the device isolated state. The value 1 + means the device is unavailable. The 0 means the device is + available. + +What: /sys/class/uacce//algorithms +Date: Feb 2020 +KernelVersion: 5.7 +Contact: linux-accelerators@lists.ozlabs.org +Description: Algorithms supported by this accelerator, separated by new line. + Can be any string and up to userspace to parse. + +What: /sys/class/uacce//region_mmio_size +Date: Feb 2020 +KernelVersion: 5.7 +Contact: linux-accelerators@lists.ozlabs.org +Description: Size (bytes) of mmio region queue file + +What: /sys/class/uacce//region_dus_size +Date: Feb 2020 +KernelVersion: 5.7 +Contact: linux-accelerators@lists.ozlabs.org +Description: Size (bytes) of dus region queue file -- cgit v1.3.1