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/nilfs2/btnode.h | 47 +++++++++++++++++++++++++++++++++++++++++++++++ 1 file changed, 47 insertions(+) create mode 100644 fs/nilfs2/btnode.h (limited to 'fs/nilfs2/btnode.h') diff --git a/fs/nilfs2/btnode.h b/fs/nilfs2/btnode.h new file mode 100644 index 000000000..4bc5612df --- /dev/null +++ b/fs/nilfs2/btnode.h @@ -0,0 +1,47 @@ +/* SPDX-License-Identifier: GPL-2.0+ */ +/* + * NILFS B-tree node cache + * + * Copyright (C) 2005-2008 Nippon Telegraph and Telephone Corporation. + * + * Written by Seiji Kihara. + * Revised by Ryusuke Konishi. + */ + +#ifndef _NILFS_BTNODE_H +#define _NILFS_BTNODE_H + +#include +#include +#include +#include + +/** + * struct nilfs_btnode_chkey_ctxt - change key context + * @oldkey: old key of block's moving content + * @newkey: new key for block's content + * @bh: buffer head of old buffer + * @newbh: buffer head of new buffer + */ +struct nilfs_btnode_chkey_ctxt { + __u64 oldkey; + __u64 newkey; + struct buffer_head *bh; + struct buffer_head *newbh; +}; + +void nilfs_init_btnc_inode(struct inode *btnc_inode); +void nilfs_btnode_cache_clear(struct address_space *); +struct buffer_head *nilfs_btnode_create_block(struct address_space *btnc, + __u64 blocknr); +int nilfs_btnode_submit_block(struct address_space *, __u64, sector_t, + blk_opf_t, struct buffer_head **, sector_t *); +void nilfs_btnode_delete(struct buffer_head *); +int nilfs_btnode_prepare_change_key(struct address_space *, + struct nilfs_btnode_chkey_ctxt *); +void nilfs_btnode_commit_change_key(struct address_space *, + struct nilfs_btnode_chkey_ctxt *); +void nilfs_btnode_abort_change_key(struct address_space *, + struct nilfs_btnode_chkey_ctxt *); + +#endif /* _NILFS_BTNODE_H */ -- cgit v1.3.1