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 --- fs/dlm/rcom.h | 26 ++++++++++++++++++++++++++ 1 file changed, 26 insertions(+) create mode 100644 fs/dlm/rcom.h (limited to 'fs/dlm/rcom.h') diff --git a/fs/dlm/rcom.h b/fs/dlm/rcom.h new file mode 100644 index 000000000..765926ae0 --- /dev/null +++ b/fs/dlm/rcom.h @@ -0,0 +1,26 @@ +/* SPDX-License-Identifier: GPL-2.0-only */ +/****************************************************************************** +******************************************************************************* +** +** Copyright (C) Sistina Software, Inc. 1997-2003 All rights reserved. +** Copyright (C) 2005-2007 Red Hat, Inc. All rights reserved. +** +** +******************************************************************************* +******************************************************************************/ + +#ifndef __RCOM_DOT_H__ +#define __RCOM_DOT_H__ + +int dlm_rcom_status(struct dlm_ls *ls, int nodeid, uint32_t status_flags, + uint64_t seq); +int dlm_rcom_names(struct dlm_ls *ls, int nodeid, char *last_name, + int last_len, uint64_t seq); +int dlm_send_rcom_lookup(struct dlm_rsb *r, int dir_nodeid, uint64_t seq); +int dlm_send_rcom_lock(struct dlm_rsb *r, struct dlm_lkb *lkb, uint64_t seq); +void dlm_receive_rcom(struct dlm_ls *ls, const struct dlm_rcom *rc, + int nodeid); +int dlm_send_ls_not_ready(int nodeid, const struct dlm_rcom *rc_in); + +#endif + -- cgit v1.3.1