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 --- tools/testing/selftests/module/Makefile | 12 ++++ tools/testing/selftests/module/config | 3 + tools/testing/selftests/module/find_symbol.sh | 81 +++++++++++++++++++++++++++ 3 files changed, 96 insertions(+) create mode 100644 tools/testing/selftests/module/Makefile create mode 100644 tools/testing/selftests/module/config create mode 100755 tools/testing/selftests/module/find_symbol.sh (limited to 'tools/testing/selftests/module') diff --git a/tools/testing/selftests/module/Makefile b/tools/testing/selftests/module/Makefile new file mode 100644 index 000000000..6132d7ddb --- /dev/null +++ b/tools/testing/selftests/module/Makefile @@ -0,0 +1,12 @@ +# SPDX-License-Identifier: GPL-2.0-only +# Makefile for module loading selftests + +# No binaries, but make sure arg-less "make" doesn't trigger "run_tests" +all: + +TEST_PROGS := find_symbol.sh + +include ../lib.mk + +# Nothing to clean up. +clean: diff --git a/tools/testing/selftests/module/config b/tools/testing/selftests/module/config new file mode 100644 index 000000000..b0c206b1a --- /dev/null +++ b/tools/testing/selftests/module/config @@ -0,0 +1,3 @@ +CONFIG_TEST_RUNTIME=y +CONFIG_TEST_RUNTIME_MODULE=y +CONFIG_TEST_KALLSYMS=m diff --git a/tools/testing/selftests/module/find_symbol.sh b/tools/testing/selftests/module/find_symbol.sh new file mode 100755 index 000000000..2c56805c9 --- /dev/null +++ b/tools/testing/selftests/module/find_symbol.sh @@ -0,0 +1,81 @@ +#!/bin/bash +# SPDX-License-Identifier: GPL-2.0-or-later OR copyleft-next-0.3.1 +# Copyright (C) 2023 Luis Chamberlain +# +# This is a stress test script for kallsyms through find_symbol() + +set -e + +# Kselftest framework requirement - SKIP code is 4. +ksft_skip=4 + +test_reqs() +{ + if ! which modprobe 2> /dev/null > /dev/null; then + echo "$0: You need modprobe installed" >&2 + exit $ksft_skip + fi + + if ! which kmod 2> /dev/null > /dev/null; then + echo "$0: You need kmod installed" >&2 + exit $ksft_skip + fi + + if ! which perf 2> /dev/null > /dev/null; then + echo "$0: You need perf installed" >&2 + exit $ksft_skip + fi + + uid=$(id -u) + if [ $uid -ne 0 ]; then + echo $msg must be run as root >&2 + exit $ksft_skip + fi +} + +load_mod() +{ + local STATS="-e duration_time" + STATS="$STATS -e user_time" + STATS="$STATS -e system_time" + STATS="$STATS -e page-faults" + local MOD=$1 + + local ARCH="$(uname -m)" + case "${ARCH}" in + x86_64) + perf stat $STATS $MODPROBE $MOD + ;; + *) + time $MODPROBE $MOD + exit 1 + ;; + esac +} + +remove_all() +{ + $MODPROBE -r test_kallsyms_b + for i in a b c d; do + $MODPROBE -r test_kallsyms_$i + done +} +test_reqs + +MODPROBE=$(