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 --- net/dcb/dcbevent.c | 30 ++++++++++++++++++++++++++++++ 1 file changed, 30 insertions(+) create mode 100644 net/dcb/dcbevent.c (limited to 'net/dcb/dcbevent.c') diff --git a/net/dcb/dcbevent.c b/net/dcb/dcbevent.c new file mode 100644 index 000000000..8620564c2 --- /dev/null +++ b/net/dcb/dcbevent.c @@ -0,0 +1,30 @@ +// SPDX-License-Identifier: GPL-2.0-only +/* + * Copyright (c) 2010, Intel Corporation. + * + * Author: John Fastabend + */ + +#include +#include +#include +#include + +static ATOMIC_NOTIFIER_HEAD(dcbevent_notif_chain); + +int register_dcbevent_notifier(struct notifier_block *nb) +{ + return atomic_notifier_chain_register(&dcbevent_notif_chain, nb); +} +EXPORT_SYMBOL(register_dcbevent_notifier); + +int unregister_dcbevent_notifier(struct notifier_block *nb) +{ + return atomic_notifier_chain_unregister(&dcbevent_notif_chain, nb); +} +EXPORT_SYMBOL(unregister_dcbevent_notifier); + +int call_dcbevent_notifiers(unsigned long val, void *v) +{ + return atomic_notifier_call_chain(&dcbevent_notif_chain, val, v); +} -- cgit v1.3.1