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 --- .../ABI/testing/sysfs-class-devfreq-event | 25 ++++++++++++++++++++++ 1 file changed, 25 insertions(+) create mode 100644 Documentation/ABI/testing/sysfs-class-devfreq-event (limited to 'Documentation/ABI/testing/sysfs-class-devfreq-event') diff --git a/Documentation/ABI/testing/sysfs-class-devfreq-event b/Documentation/ABI/testing/sysfs-class-devfreq-event new file mode 100644 index 000000000..dbe48495e --- /dev/null +++ b/Documentation/ABI/testing/sysfs-class-devfreq-event @@ -0,0 +1,25 @@ +What: /sys/class/devfreq-event/event/ +Date: January 2017 +Contact: Chanwoo Choi +Description: + Provide a place in sysfs for the devfreq-event objects. + This allows accessing various devfreq-event specific variables. + The name of devfreq-event object denoted as 'event' which + includes the unique number of 'x' for each devfreq-event object. + +What: /sys/class/devfreq-event/event/name +Date: January 2017 +Contact: Chanwoo Choi +Description: + The /sys/class/devfreq-event/event/name attribute contains + the name of the devfreq-event object. This attribute is + read-only. + +What: /sys/class/devfreq-event/event/enable_count +Date: January 2017 +Contact: Chanwoo Choi +Description: + The /sys/class/devfreq-event/event/enable_count attribute + contains the reference count to enable the devfreq-event + object. If the device is enabled, the value of attribute is + greater than zero. -- cgit v1.3.1