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/rust/arch-support.rst | 26 ++++++++++++++++++++++++++ 1 file changed, 26 insertions(+) create mode 100644 Documentation/rust/arch-support.rst (limited to 'Documentation/rust/arch-support.rst') diff --git a/Documentation/rust/arch-support.rst b/Documentation/rust/arch-support.rst new file mode 100644 index 000000000..4f980815e --- /dev/null +++ b/Documentation/rust/arch-support.rst @@ -0,0 +1,26 @@ +.. SPDX-License-Identifier: GPL-2.0 + +Arch Support +============ + +Currently, the Rust compiler (``rustc``) uses LLVM for code generation, +which limits the supported architectures that can be targeted. In addition, +support for building the kernel with LLVM/Clang varies (please see +Documentation/kbuild/llvm.rst). This support is needed for ``bindgen`` +which uses ``libclang``. + +Below is a general summary of architectures that currently work. Level of +support corresponds to ``S`` values in the ``MAINTAINERS`` file. + +============= ================ ============================================== +Architecture Level of support Constraints +============= ================ ============================================== +``arm`` Maintained ARMv7 Little Endian only. +``arm64`` Maintained Little Endian only. +``loongarch`` Maintained \- +``riscv`` Maintained ``riscv64`` and LLVM/Clang only. +``s390`` Maintained ``CONFIG_EXPOLINE`` must be disabled. +``um`` Maintained \- +``x86`` Maintained ``x86_64`` only. +============= ================ ============================================== + -- cgit v1.3.1