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/main.c | 105 ++++++++++++++++++++++++++++++++++++++++++++++++++++++++++ 1 file changed, 105 insertions(+) create mode 100644 fs/dlm/main.c (limited to 'fs/dlm/main.c') diff --git a/fs/dlm/main.c b/fs/dlm/main.c new file mode 100644 index 000000000..a44d16da7 --- /dev/null +++ b/fs/dlm/main.c @@ -0,0 +1,105 @@ +// 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. +** +** +******************************************************************************* +******************************************************************************/ + +#include + +#include "dlm_internal.h" +#include "lockspace.h" +#include "lock.h" +#include "user.h" +#include "memory.h" +#include "config.h" +#include "midcomms.h" + +#define CREATE_TRACE_POINTS +#include + +struct workqueue_struct *dlm_wq; + +static int __init init_dlm(void) +{ + int error; + + error = dlm_memory_init(); + if (error) + goto out; + + dlm_midcomms_init(); + + error = dlm_lockspace_init(); + if (error) + goto out_mem; + + error = dlm_config_init(); + if (error) + goto out_lockspace; + + dlm_register_debugfs(); + + error = dlm_user_init(); + if (error) + goto out_debug; + + error = dlm_plock_init(); + if (error) + goto out_user; + + dlm_wq = alloc_workqueue("dlm_wq", WQ_PERCPU, 0); + if (!dlm_wq) { + error = -ENOMEM; + goto out_plock; + } + + printk("DLM installed\n"); + + return 0; + + out_plock: + dlm_plock_exit(); + out_user: + dlm_user_exit(); + out_debug: + dlm_unregister_debugfs(); + dlm_config_exit(); + out_lockspace: + dlm_lockspace_exit(); + out_mem: + dlm_midcomms_exit(); + dlm_memory_exit(); + out: + return error; +} + +static void __exit exit_dlm(void) +{ + /* be sure every pending work e.g. freeing is done */ + destroy_workqueue(dlm_wq); + dlm_plock_exit(); + dlm_user_exit(); + dlm_config_exit(); + dlm_lockspace_exit(); + dlm_midcomms_exit(); + dlm_unregister_debugfs(); + dlm_memory_exit(); +} + +module_init(init_dlm); +module_exit(exit_dlm); + +MODULE_DESCRIPTION("Distributed Lock Manager"); +MODULE_AUTHOR("Red Hat, Inc."); +MODULE_LICENSE("GPL"); + +EXPORT_SYMBOL_GPL(dlm_new_lockspace); +EXPORT_SYMBOL_GPL(dlm_release_lockspace); +EXPORT_SYMBOL_GPL(dlm_lock); +EXPORT_SYMBOL_GPL(dlm_unlock); + -- cgit v1.3.1