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/admin-guide/abi-testing.rst | 22 ++++++++++++++++++++++ 1 file changed, 22 insertions(+) create mode 100644 Documentation/admin-guide/abi-testing.rst (limited to 'Documentation/admin-guide/abi-testing.rst') diff --git a/Documentation/admin-guide/abi-testing.rst b/Documentation/admin-guide/abi-testing.rst new file mode 100644 index 000000000..6153ebd38 --- /dev/null +++ b/Documentation/admin-guide/abi-testing.rst @@ -0,0 +1,22 @@ +.. SPDX-License-Identifier: GPL-2.0 + +ABI testing symbols +=================== + +Documents interfaces that are felt to be stable, +as the main development of this interface has been completed. + +The interface can be changed to add new features, but the +current interface will not break by doing this, unless grave +errors or security problems are found in them. + +Userspace programs can start to rely on these interfaces, but they must +be aware of changes that can occur before these interfaces move to +be marked stable. + +Programs that use these interfaces are strongly encouraged to add their +name to the description of these interfaces, so that the kernel +developers can easily notify them if any changes occur. + +.. kernel-abi:: testing + :no-files: -- cgit v1.3.1