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 --- security/ipe/ipe.h | 28 ++++++++++++++++++++++++++++ 1 file changed, 28 insertions(+) create mode 100644 security/ipe/ipe.h (limited to 'security/ipe/ipe.h') diff --git a/security/ipe/ipe.h b/security/ipe/ipe.h new file mode 100644 index 000000000..25cfdb8f0 --- /dev/null +++ b/security/ipe/ipe.h @@ -0,0 +1,28 @@ +/* SPDX-License-Identifier: GPL-2.0 */ +/* + * Copyright (C) 2020-2024 Microsoft Corporation. All rights reserved. + */ + +#ifndef _IPE_H +#define _IPE_H + +#ifdef pr_fmt +#undef pr_fmt +#endif +#define pr_fmt(fmt) "ipe: " fmt + +#include +struct ipe_superblock *ipe_sb(const struct super_block *sb); + +extern bool ipe_enabled; + +#ifdef CONFIG_IPE_PROP_DM_VERITY +struct ipe_bdev *ipe_bdev(struct block_device *b); +#endif /* CONFIG_IPE_PROP_DM_VERITY */ +#ifdef CONFIG_IPE_PROP_FS_VERITY_BUILTIN_SIG +struct ipe_inode *ipe_inode(const struct inode *inode); +#endif /* CONFIG_IPE_PROP_FS_VERITY_BUILTIN_SIG */ + +int ipe_init_securityfs(void); + +#endif /* _IPE_H */ -- cgit v1.3.1