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-eud | 9 +++++++++ 1 file changed, 9 insertions(+) create mode 100644 Documentation/ABI/testing/sysfs-driver-eud (limited to 'Documentation/ABI/testing/sysfs-driver-eud') diff --git a/Documentation/ABI/testing/sysfs-driver-eud b/Documentation/ABI/testing/sysfs-driver-eud new file mode 100644 index 000000000..2bab0db2d --- /dev/null +++ b/Documentation/ABI/testing/sysfs-driver-eud @@ -0,0 +1,9 @@ +What: /sys/bus/platform/drivers/qcom_eud/.../enable +Date: February 2022 +Contact: Souradeep Chowdhury +Description: + The Enable/Disable sysfs interface for Embedded + USB Debugger(EUD). This enables and disables the + EUD based on a 1 or a 0 value. By enabling EUD, + the user is able to activate the mini-usb hub of + EUD for debug and trace capabilities. -- cgit v1.3.1