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/debugfs/internal.h | 58 +++++++++++++++++++++++++++++++++++++++++++++++++++ 1 file changed, 58 insertions(+) create mode 100644 fs/debugfs/internal.h (limited to 'fs/debugfs/internal.h') diff --git a/fs/debugfs/internal.h b/fs/debugfs/internal.h new file mode 100644 index 000000000..c95699b27 --- /dev/null +++ b/fs/debugfs/internal.h @@ -0,0 +1,58 @@ +/* SPDX-License-Identifier: GPL-2.0 */ +/* + * internal.h - declarations internal to debugfs + * + * Copyright (C) 2016 Nicolai Stange + */ + +#ifndef _DEBUGFS_INTERNAL_H_ +#define _DEBUGFS_INTERNAL_H_ +#include + +struct file_operations; + +struct debugfs_inode_info { + struct inode vfs_inode; + union { + const void *raw; + const struct file_operations *real_fops; + const struct debugfs_short_fops *short_fops; + debugfs_automount_t automount; + }; + void *aux; +}; + +static inline struct debugfs_inode_info *DEBUGFS_I(struct inode *inode) +{ + return container_of(inode, struct debugfs_inode_info, vfs_inode); +} + +/* declared over in file.c */ +extern const struct file_operations debugfs_noop_file_operations; +extern const struct file_operations debugfs_open_proxy_file_operations; +extern const struct file_operations debugfs_full_proxy_file_operations; +extern const struct file_operations debugfs_full_short_proxy_file_operations; + +struct debugfs_fsdata { + const struct file_operations *real_fops; + const struct debugfs_short_fops *short_fops; + struct { + refcount_t active_users; + struct completion active_users_drained; + + /* protect cancellations */ + struct mutex cancellations_mtx; + struct list_head cancellations; + unsigned int methods; + }; +}; + +enum { + HAS_READ = 1, + HAS_WRITE = 2, + HAS_LSEEK = 4, + HAS_POLL = 8, + HAS_IOCTL = 16 +}; + +#endif /* _DEBUGFS_INTERNAL_H_ */ -- cgit v1.3.1