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/cachefiles/Kconfig | 40 ++++++++++++++++++++++++++++++++++++++++ 1 file changed, 40 insertions(+) create mode 100644 fs/cachefiles/Kconfig (limited to 'fs/cachefiles/Kconfig') diff --git a/fs/cachefiles/Kconfig b/fs/cachefiles/Kconfig new file mode 100644 index 000000000..c5a070550 --- /dev/null +++ b/fs/cachefiles/Kconfig @@ -0,0 +1,40 @@ +# SPDX-License-Identifier: GPL-2.0-only + +config CACHEFILES + tristate "Filesystem caching on files" + depends on NETFS_SUPPORT && FSCACHE && BLOCK + help + This permits use of a mounted filesystem as a cache for other + filesystems - primarily networking filesystems - thus allowing fast + local disk to enhance the speed of slower devices. + + See Documentation/filesystems/caching/cachefiles.rst for more + information. + +config CACHEFILES_DEBUG + bool "Debug CacheFiles" + depends on CACHEFILES + help + This permits debugging to be dynamically enabled in the filesystem + caching on files module. If this is set, the debugging output may be + enabled by setting bits in /sys/modules/cachefiles/parameter/debug or + by including a debugging specifier in /etc/cachefilesd.conf. + +config CACHEFILES_ERROR_INJECTION + bool "Provide error injection for cachefiles" + depends on CACHEFILES && SYSCTL + help + This permits error injection to be enabled in cachefiles whilst a + cache is in service. + +config CACHEFILES_ONDEMAND + bool "Support for on-demand read" + depends on CACHEFILES + default n + help + This permits userspace to enable the cachefiles on-demand read mode. + In this mode, when a cache miss occurs, responsibility for fetching + the data lies with the cachefiles backend instead of with the netfs + and is delegated to userspace. + + If unsure, say N. -- cgit v1.3.1