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 --- drivers/md/dm-vdo/string-utils.h | 23 +++++++++++++++++++++++ 1 file changed, 23 insertions(+) create mode 100644 drivers/md/dm-vdo/string-utils.h (limited to 'drivers/md/dm-vdo/string-utils.h') diff --git a/drivers/md/dm-vdo/string-utils.h b/drivers/md/dm-vdo/string-utils.h new file mode 100644 index 000000000..96eecd38b --- /dev/null +++ b/drivers/md/dm-vdo/string-utils.h @@ -0,0 +1,23 @@ +/* SPDX-License-Identifier: GPL-2.0-only */ +/* + * Copyright 2023 Red Hat + */ + +#ifndef VDO_STRING_UTILS_H +#define VDO_STRING_UTILS_H + +#include +#include + +/* Utilities related to string manipulation */ + +static inline const char *vdo_bool_to_string(bool value) +{ + return value ? "true" : "false"; +} + +/* Append a formatted string to the end of a buffer. */ +char *vdo_append_to_buffer(char *buffer, char *buf_end, const char *fmt, ...) + __printf(3, 4); + +#endif /* VDO_STRING_UTILS_H */ -- cgit v1.3.1