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-kernel-livepatch | 95 ++++++++++++++++++++++++ 1 file changed, 95 insertions(+) create mode 100644 Documentation/ABI/testing/sysfs-kernel-livepatch (limited to 'Documentation/ABI/testing/sysfs-kernel-livepatch') diff --git a/Documentation/ABI/testing/sysfs-kernel-livepatch b/Documentation/ABI/testing/sysfs-kernel-livepatch new file mode 100644 index 000000000..3c3f36b32 --- /dev/null +++ b/Documentation/ABI/testing/sysfs-kernel-livepatch @@ -0,0 +1,95 @@ +What: /sys/kernel/livepatch +Date: Nov 2014 +KernelVersion: 3.19.0 +Contact: live-patching@vger.kernel.org +Description: + Interface for kernel live patching + + The /sys/kernel/livepatch directory contains subdirectories for + each loaded live patch module. + +What: /sys/kernel/livepatch/ +Date: Nov 2014 +KernelVersion: 3.19.0 +Contact: live-patching@vger.kernel.org +Description: + The patch directory contains subdirectories for each kernel + object (vmlinux or a module) in which it patched functions. + +What: /sys/kernel/livepatch//enabled +Date: Nov 2014 +KernelVersion: 3.19.0 +Contact: live-patching@vger.kernel.org +Description: + A writable attribute that indicates whether the patched + code is currently applied. Writing 0 will disable the patch + while writing 1 will re-enable the patch. + +What: /sys/kernel/livepatch//transition +Date: Feb 2017 +KernelVersion: 4.12.0 +Contact: live-patching@vger.kernel.org +Description: + An attribute which indicates whether the patch is currently in + transition. + +What: /sys/kernel/livepatch//force +Date: Nov 2017 +KernelVersion: 4.15.0 +Contact: live-patching@vger.kernel.org +Description: + A writable attribute that allows administrator to affect the + course of an existing transition. Writing 1 clears + TIF_PATCH_PENDING flag of all tasks and thus forces the tasks to + the patched or unpatched state. Administrator should not + use this feature without a clearance from a patch + distributor. Removal (rmmod) of patch modules is permanently + disabled when the feature is used. See + Documentation/livepatch/livepatch.rst for more information. + +What: /sys/kernel/livepatch//replace +Date: Jun 2024 +KernelVersion: 6.11.0 +Contact: live-patching@vger.kernel.org +Description: + An attribute which indicates whether the patch supports + atomic-replace. + +What: /sys/kernel/livepatch//stack_order +Date: Jan 2025 +KernelVersion: 6.14.0 +Description: + This attribute specifies the sequence in which live patch modules + are applied to the system. If multiple live patches modify the same + function, the implementation with the biggest 'stack_order' number + is used, unless a transition is currently in progress. + +What: /sys/kernel/livepatch// +Date: Nov 2014 +KernelVersion: 3.19.0 +Contact: live-patching@vger.kernel.org +Description: + The object directory contains subdirectories for each function + that is patched within the object. + +What: /sys/kernel/livepatch///patched +Date: August 2022 +KernelVersion: 6.1.0 +Contact: live-patching@vger.kernel.org +Description: + An attribute which indicates whether the object is currently + patched. + +What: /sys/kernel/livepatch/// +Date: Nov 2014 +KernelVersion: 3.19.0 +Contact: live-patching@vger.kernel.org +Description: + The function directory contains attributes regarding the + properties and state of the patched function. + + The directory name contains the patched function name and a + sympos number corresponding to the nth occurrence of the symbol + name in kallsyms for the patched object. + + There are currently no such attributes. -- cgit v1.3.1