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-class-vduse | 33 +++++++++++++++++++++++++++++ 1 file changed, 33 insertions(+) create mode 100644 Documentation/ABI/testing/sysfs-class-vduse (limited to 'Documentation/ABI/testing/sysfs-class-vduse') diff --git a/Documentation/ABI/testing/sysfs-class-vduse b/Documentation/ABI/testing/sysfs-class-vduse new file mode 100644 index 000000000..2f2bc5c8f --- /dev/null +++ b/Documentation/ABI/testing/sysfs-class-vduse @@ -0,0 +1,33 @@ +What: /sys/class/vduse/ +Date: Oct 2021 +KernelVersion: 5.15 +Contact: Yongji Xie +Description: + The vduse/ class sub-directory belongs to the VDUSE + framework and provides a sysfs interface for configuring + VDUSE devices. + +What: /sys/class/vduse/control/ +Date: Oct 2021 +KernelVersion: 5.15 +Contact: Yongji Xie +Description: + This directory entry is created for the control device + of VDUSE framework. + +What: /sys/class/vduse// +Date: Oct 2021 +KernelVersion: 5.15 +Contact: Yongji Xie +Description: + This directory entry is created when a VDUSE device is + created via the control device. + +What: /sys/class/vduse//msg_timeout +Date: Oct 2021 +KernelVersion: 5.15 +Contact: Yongji Xie +Description: + (RW) The timeout (in seconds) for waiting for the control + message's response from userspace. Default value is 30s. + Writing a '0' to the file means to disable the timeout. -- cgit v1.3.1