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 --- drivers/clocksource/timer-probe.c | 45 +++++++++++++++++++++++++++++++++++++++ 1 file changed, 45 insertions(+) create mode 100644 drivers/clocksource/timer-probe.c (limited to 'drivers/clocksource/timer-probe.c') diff --git a/drivers/clocksource/timer-probe.c b/drivers/clocksource/timer-probe.c new file mode 100644 index 000000000..b7860bc0d --- /dev/null +++ b/drivers/clocksource/timer-probe.c @@ -0,0 +1,45 @@ +// SPDX-License-Identifier: GPL-2.0-only +/* + * Copyright (c) 2012, NVIDIA CORPORATION. All rights reserved. + */ + +#include +#include +#include +#include + +extern struct of_device_id __timer_of_table[]; + +static const struct of_device_id __timer_of_table_sentinel + __used __section("__timer_of_table_end"); + +void __init timer_probe(void) +{ + struct device_node *np; + const struct of_device_id *match; + of_init_fn_1_ret init_func_ret; + unsigned timers = 0; + int ret; + + for_each_matching_node_and_match(np, __timer_of_table, &match) { + if (!of_device_is_available(np)) + continue; + + init_func_ret = match->data; + + ret = init_func_ret(np); + if (ret) { + if (ret != -EPROBE_DEFER) + pr_err("Failed to initialize '%pOF': %d\n", np, + ret); + continue; + } + + timers++; + } + + timers += acpi_probe_device_table(timer); + + if (!timers) + pr_crit("%s: no matching timers found\n", __func__); +} -- cgit v1.3.1