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/tracepoint.py | 55 +++++++++++++++++++++++++++++++++++++++++ 1 file changed, 55 insertions(+) create mode 100755 tools/perf/python/tracepoint.py (limited to 'tools/perf/python/tracepoint.py') diff --git a/tools/perf/python/tracepoint.py b/tools/perf/python/tracepoint.py new file mode 100755 index 000000000..15b0c8268 --- /dev/null +++ b/tools/perf/python/tracepoint.py @@ -0,0 +1,55 @@ +#! /usr/bin/env python +# SPDX-License-Identifier: GPL-2.0 +# -*- python -*- +# -*- coding: utf-8 -*- + +import perf + +def change_proctitle(): + try: + import setproctitle + setproctitle.setproctitle("tracepoint.py") + except: + print("Install the setproctitle python package to help with top and friends") + +def main(): + change_proctitle() + cpus = perf.cpu_map() + threads = perf.thread_map(-1) + evlist = perf.parse_events("sched:sched_switch", cpus, threads) + # Disable tracking of mmaps and similar that are unnecessary. + for ev in evlist: + ev.tracking = False + # Configure evsels with default record options. + evlist.config() + # Simplify the sample_type and read_format of evsels + for ev in evlist: + ev.sample_type = ev.sample_type & ~perf.SAMPLE_IP + ev.read_format = 0 + + evlist.open() + evlist.mmap() + evlist.enable(); + + while True: + evlist.poll(timeout = -1) + for cpu in cpus: + event = evlist.read_on_cpu(cpu) + if not event: + continue + + if not isinstance(event, perf.sample_event): + continue + + print("time %u prev_comm=%s prev_pid=%d prev_prio=%d prev_state=0x%x ==> next_comm=%s next_pid=%d next_prio=%d" % ( + event.sample_time, + event.prev_comm, + event.prev_pid, + event.prev_prio, + event.prev_state, + event.next_comm, + event.next_pid, + event.next_prio)) + +if __name__ == '__main__': + main() -- cgit v1.3.1