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/lock.h | 85 +++++++++++++++++++++++++++++++++++++++++++++++++++++++++++ 1 file changed, 85 insertions(+) create mode 100644 fs/dlm/lock.h (limited to 'fs/dlm/lock.h') diff --git a/fs/dlm/lock.h b/fs/dlm/lock.h new file mode 100644 index 000000000..b23d7b854 --- /dev/null +++ b/fs/dlm/lock.h @@ -0,0 +1,85 @@ +/* SPDX-License-Identifier: GPL-2.0-only */ +/****************************************************************************** +******************************************************************************* +** +** Copyright (C) 2005-2007 Red Hat, Inc. All rights reserved. +** +** +******************************************************************************* +******************************************************************************/ + +#ifndef __LOCK_DOT_H__ +#define __LOCK_DOT_H__ + +void dlm_dump_rsb(struct dlm_rsb *r); +void dlm_dump_rsb_name(struct dlm_ls *ls, const char *name, int len); +void dlm_print_lkb(struct dlm_lkb *lkb); +void dlm_receive_message_saved(struct dlm_ls *ls, const struct dlm_message *ms, + uint32_t saved_seq); +void dlm_receive_buffer(const union dlm_packet *p, int nodeid); +int dlm_modes_compat(int mode1, int mode2); +void free_inactive_rsb(struct dlm_rsb *r); +void dlm_put_rsb(struct dlm_rsb *r); +void dlm_hold_rsb(struct dlm_rsb *r); +int dlm_put_lkb(struct dlm_lkb *lkb); +int dlm_lock_recovery_try(struct dlm_ls *ls); +void dlm_lock_recovery(struct dlm_ls *ls); +void dlm_unlock_recovery(struct dlm_ls *ls); +void dlm_rsb_scan(struct timer_list *timer); +void resume_scan_timer(struct dlm_ls *ls); + +int dlm_master_lookup(struct dlm_ls *ls, int from_nodeid, const char *name, + int len, unsigned int flags, int *r_nodeid, int *result); + +int dlm_search_rsb_tree(struct rhashtable *rhash, const void *name, int len, + struct dlm_rsb **r_ret); + +void dlm_recover_purge(struct dlm_ls *ls, const struct list_head *root_list); +void dlm_purge_mstcpy_locks(struct dlm_rsb *r); +void dlm_recover_grant(struct dlm_ls *ls); +int dlm_recover_waiters_post(struct dlm_ls *ls); +void dlm_recover_waiters_pre(struct dlm_ls *ls); +int dlm_recover_master_copy(struct dlm_ls *ls, const struct dlm_rcom *rc, + __le32 *rl_remid, __le32 *rl_result); +int dlm_recover_process_copy(struct dlm_ls *ls, const struct dlm_rcom *rc, + uint64_t seq); + +int dlm_user_request(struct dlm_ls *ls, struct dlm_user_args *ua, int mode, + uint32_t flags, void *name, unsigned int namelen); +int dlm_user_convert(struct dlm_ls *ls, struct dlm_user_args *ua_tmp, + int mode, uint32_t flags, uint32_t lkid, char *lvb_in); +int dlm_user_adopt_orphan(struct dlm_ls *ls, struct dlm_user_args *ua_tmp, + int mode, uint32_t flags, void *name, unsigned int namelen, + uint32_t *lkid); +int dlm_user_unlock(struct dlm_ls *ls, struct dlm_user_args *ua_tmp, + uint32_t flags, uint32_t lkid, char *lvb_in); +int dlm_user_cancel(struct dlm_ls *ls, struct dlm_user_args *ua_tmp, + uint32_t flags, uint32_t lkid); +int dlm_user_purge(struct dlm_ls *ls, struct dlm_user_proc *proc, + int nodeid, int pid); +int dlm_user_deadlock(struct dlm_ls *ls, uint32_t flags, uint32_t lkid); +void dlm_clear_proc_locks(struct dlm_ls *ls, struct dlm_user_proc *proc); +int dlm_debug_add_lkb(struct dlm_ls *ls, uint32_t lkb_id, char *name, int len, + int lkb_nodeid, unsigned int lkb_flags, int lkb_status); +int dlm_debug_add_lkb_to_waiters(struct dlm_ls *ls, uint32_t lkb_id, + int mstype, int to_nodeid); + +static inline int is_master(struct dlm_rsb *r) +{ + WARN_ON_ONCE(r->res_nodeid == -1); + + return !r->res_nodeid; +} + +static inline void lock_rsb(struct dlm_rsb *r) +{ + spin_lock_bh(&r->res_lock); +} + +static inline void unlock_rsb(struct dlm_rsb *r) +{ + spin_unlock_bh(&r->res_lock); +} + +#endif + -- cgit v1.3.1