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/memory.h | 33 +++++++++++++++++++++++++++++++++ 1 file changed, 33 insertions(+) create mode 100644 fs/dlm/memory.h (limited to 'fs/dlm/memory.h') diff --git a/fs/dlm/memory.h b/fs/dlm/memory.h new file mode 100644 index 000000000..551b6b788 --- /dev/null +++ b/fs/dlm/memory.h @@ -0,0 +1,33 @@ +/* SPDX-License-Identifier: GPL-2.0-only */ +/****************************************************************************** +******************************************************************************* +** +** Copyright (C) Sistina Software, Inc. 1997-2003 All rights reserved. +** Copyright (C) 2004-2007 Red Hat, Inc. All rights reserved. +** +** +******************************************************************************* +******************************************************************************/ + +#ifndef __MEMORY_DOT_H__ +#define __MEMORY_DOT_H__ + +int dlm_memory_init(void); +void dlm_memory_exit(void); +struct dlm_rsb *dlm_allocate_rsb(void); +void dlm_free_rsb(struct dlm_rsb *r); +struct dlm_lkb *dlm_allocate_lkb(void); +void dlm_free_lkb(struct dlm_lkb *l); +char *dlm_allocate_lvb(struct dlm_ls *ls); +void dlm_free_lvb(char *l); +struct dlm_mhandle *dlm_allocate_mhandle(void); +void dlm_free_mhandle(struct dlm_mhandle *mhandle); +struct writequeue_entry *dlm_allocate_writequeue(void); +void dlm_free_writequeue(struct writequeue_entry *writequeue); +struct dlm_msg *dlm_allocate_msg(void); +void dlm_free_msg(struct dlm_msg *msg); +struct dlm_callback *dlm_allocate_cb(void); +void dlm_free_cb(struct dlm_callback *cb); + +#endif /* __MEMORY_DOT_H__ */ + -- cgit v1.3.1