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/perf/python/counting.py | 36 ++++++++++++++++++++++++++++++++++++ 1 file changed, 36 insertions(+) create mode 100755 tools/perf/python/counting.py (limited to 'tools/perf/python/counting.py') diff --git a/tools/perf/python/counting.py b/tools/perf/python/counting.py new file mode 100755 index 000000000..02121d2bb --- /dev/null +++ b/tools/perf/python/counting.py @@ -0,0 +1,36 @@ +#!/usr/bin/env python3 +# SPDX-License-Identifier: GPL-2.0 +# -*- python -*- +# -*- coding: utf-8 -*- + +import argparse +import perf + +def main(event: str): + evlist = perf.parse_events(event) + + for evsel in evlist: + evsel.read_format = perf.FORMAT_TOTAL_TIME_ENABLED | perf.FORMAT_TOTAL_TIME_RUNNING + + evlist.open() + evlist.enable() + + count = 100000 + while count > 0: + count -= 1 + + evlist.disable() + + for evsel in evlist: + for cpu in evsel.cpus(): + for thread in evsel.threads(): + counts = evsel.read(cpu, thread) + print(f"For {evsel} val: {counts.val} enable: {counts.ena} run: {counts.run}") + + evlist.close() + +if __name__ == '__main__': + ap = argparse.ArgumentParser() + ap.add_argument('-e', '--event', help="Events to open", default="cpu-clock,task-clock") + args = ap.parse_args() + main(args.event) -- cgit v1.3.1