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-xdata | 49 ++++++++++++++++++++++++++++ 1 file changed, 49 insertions(+) create mode 100644 Documentation/ABI/testing/sysfs-driver-xdata (limited to 'Documentation/ABI/testing/sysfs-driver-xdata') diff --git a/Documentation/ABI/testing/sysfs-driver-xdata b/Documentation/ABI/testing/sysfs-driver-xdata new file mode 100644 index 000000000..f574e8e6d --- /dev/null +++ b/Documentation/ABI/testing/sysfs-driver-xdata @@ -0,0 +1,49 @@ +What: /sys/class/misc/drivers/dw-xdata-pcie./write +Date: April 2021 +KernelVersion: 5.13 +Contact: Gustavo Pimentel +Description: Allows the user to enable the PCIe traffic generator which + will create write TLPs frames - from the Root Complex to the + Endpoint direction or to disable the PCIe traffic generator + in all directions. + + Write y/1/on to enable, n/0/off to disable + + Usage e.g. + echo 1 > /sys/class/misc/dw-xdata-pcie./write + or + echo 0 > /sys/class/misc/dw-xdata-pcie./write + + The user can read the current PCIe link throughput generated + through this generator in MB/s. + + Usage e.g. + cat /sys/class/misc/dw-xdata-pcie./write + 204 + + The file is read and write. + +What: /sys/class/misc/dw-xdata-pcie./read +Date: April 2021 +KernelVersion: 5.13 +Contact: Gustavo Pimentel +Description: Allows the user to enable the PCIe traffic generator which + will create read TLPs frames - from the Endpoint to the Root + Complex direction or to disable the PCIe traffic generator + in all directions. + + Write y/1/on to enable, n/0/off to disable + + Usage e.g. + echo 1 > /sys/class/misc/dw-xdata-pcie./read + or + echo 0 > /sys/class/misc/dw-xdata-pcie./read + + The user can read the current PCIe link throughput generated + through this generator in MB/s. + + Usage e.g. + cat /sys/class/misc/dw-xdata-pcie./read + 199 + + The file is read and write. -- cgit v1.3.1