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/sysfs/sysfs.h | 43 +++++++++++++++++++++++++++++++++++++++++++ 1 file changed, 43 insertions(+) create mode 100644 fs/sysfs/sysfs.h (limited to 'fs/sysfs/sysfs.h') diff --git a/fs/sysfs/sysfs.h b/fs/sysfs/sysfs.h new file mode 100644 index 000000000..f4583dcaf --- /dev/null +++ b/fs/sysfs/sysfs.h @@ -0,0 +1,43 @@ +/* SPDX-License-Identifier: GPL-2.0 */ +/* + * fs/sysfs/sysfs.h - sysfs internal header file + * + * Copyright (c) 2001-3 Patrick Mochel + * Copyright (c) 2007 SUSE Linux Products GmbH + * Copyright (c) 2007 Tejun Heo + */ + +#ifndef __SYSFS_INTERNAL_H +#define __SYSFS_INTERNAL_H + +#include + +/* + * mount.c + */ +extern struct kernfs_node *sysfs_root_kn; + +/* + * dir.c + */ +extern spinlock_t sysfs_symlink_target_lock; + +void sysfs_warn_dup(struct kernfs_node *parent, const char *name); + +/* + * file.c + */ +int sysfs_add_file_mode_ns(struct kernfs_node *parent, + const struct attribute *attr, umode_t amode, kuid_t uid, + kgid_t gid, const struct ns_common *ns); +int sysfs_add_bin_file_mode_ns(struct kernfs_node *parent, + const struct bin_attribute *battr, umode_t mode, size_t size, + kuid_t uid, kgid_t gid, const struct ns_common *ns); + +/* + * symlink.c + */ +int sysfs_create_link_sd(struct kernfs_node *kn, struct kobject *target, + const char *name); + +#endif /* __SYSFS_INTERNAL_H */ -- cgit v1.3.1