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 --- arch/powerpc/tools/checkpatch.sh | 22 ++++++++++++++++++++++ 1 file changed, 22 insertions(+) create mode 100755 arch/powerpc/tools/checkpatch.sh (limited to 'arch/powerpc/tools/checkpatch.sh') diff --git a/arch/powerpc/tools/checkpatch.sh b/arch/powerpc/tools/checkpatch.sh new file mode 100755 index 000000000..91c04802e --- /dev/null +++ b/arch/powerpc/tools/checkpatch.sh @@ -0,0 +1,22 @@ +#!/bin/bash +# SPDX-License-Identifier: GPL-2.0+ +# Copyright 2018, Michael Ellerman, IBM Corporation. +# +# Wrapper around checkpatch that uses our preferred settings + +script_base=$(realpath $(dirname $0)) + +exec $script_base/../../../scripts/checkpatch.pl \ + --subjective \ + --no-summary \ + --show-types \ + --ignore ARCH_INCLUDE_LINUX \ + --ignore BIT_MACRO \ + --ignore COMPARISON_TO_NULL \ + --ignore EMAIL_SUBJECT \ + --ignore FILE_PATH_CHANGES \ + --ignore GLOBAL_INITIALISERS \ + --ignore LINE_SPACING \ + --ignore MULTIPLE_ASSIGNMENTS \ + --ignore DT_SPLIT_BINDING_PATCH \ + $@ -- cgit v1.3.1