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/midcomms.h | 42 ++++++++++++++++++++++++++++++++++++++++++ 1 file changed, 42 insertions(+) create mode 100644 fs/dlm/midcomms.h (limited to 'fs/dlm/midcomms.h') diff --git a/fs/dlm/midcomms.h b/fs/dlm/midcomms.h new file mode 100644 index 000000000..7fad1d170 --- /dev/null +++ b/fs/dlm/midcomms.h @@ -0,0 +1,42 @@ +/* SPDX-License-Identifier: GPL-2.0-only */ +/****************************************************************************** +******************************************************************************* +** +** Copyright (C) Sistina Software, Inc. 1997-2003 All rights reserved. +** Copyright (C) 2004-2005 Red Hat, Inc. All rights reserved. +** +** +******************************************************************************* +******************************************************************************/ + +#ifndef __MIDCOMMS_DOT_H__ +#define __MIDCOMMS_DOT_H__ + +struct midcomms_node; + +int dlm_validate_incoming_buffer(int nodeid, unsigned char *buf, int len); +int dlm_process_incoming_buffer(int nodeid, unsigned char *buf, int buflen); +struct dlm_mhandle *dlm_midcomms_get_mhandle(int nodeid, int len, char **ppc); +void dlm_midcomms_commit_mhandle(struct dlm_mhandle *mh, const void *name, + int namelen); +int dlm_midcomms_addr(int nodeid, struct sockaddr_storage *addr); +void dlm_midcomms_version_wait(void); +int dlm_midcomms_close(int nodeid); +int dlm_midcomms_start(void); +void dlm_midcomms_stop(void); +void dlm_midcomms_init(void); +void dlm_midcomms_exit(void); +void dlm_midcomms_shutdown(void); +void dlm_midcomms_add_member(int nodeid); +void dlm_midcomms_remove_member(int nodeid); +void dlm_midcomms_unack_msg_resend(int nodeid); +const char *dlm_midcomms_state(struct midcomms_node *node); +unsigned long dlm_midcomms_flags(struct midcomms_node *node); +int dlm_midcomms_send_queue_cnt(struct midcomms_node *node); +uint32_t dlm_midcomms_version(struct midcomms_node *node); +int dlm_midcomms_rawmsg_send(struct midcomms_node *node, void *buf, + int buflen); +struct kmem_cache *dlm_midcomms_cache_create(void); + +#endif /* __MIDCOMMS_DOT_H__ */ + -- cgit v1.3.1