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/bcache/Kconfig | 30 ++++++++++++++++++++++++++++++ 1 file changed, 30 insertions(+) create mode 100644 drivers/md/bcache/Kconfig (limited to 'drivers/md/bcache/Kconfig') diff --git a/drivers/md/bcache/Kconfig b/drivers/md/bcache/Kconfig new file mode 100644 index 000000000..b2d10063d --- /dev/null +++ b/drivers/md/bcache/Kconfig @@ -0,0 +1,30 @@ +# SPDX-License-Identifier: GPL-2.0-only + +config BCACHE + tristate "Block device as cache" + select BLOCK_HOLDER_DEPRECATED if SYSFS + select CRC64 + select CLOSURES + help + Allows a block device to be used as cache for other devices; uses + a btree for indexing and the layout is optimized for SSDs. + + See Documentation/admin-guide/bcache.rst for details. + +config BCACHE_DEBUG + bool "Bcache debugging" + depends on BCACHE + help + Don't select this option unless you're a developer + + Enables extra debugging tools, allows expensive runtime checks to be + turned on. + +config BCACHE_ASYNC_REGISTRATION + bool "Asynchronous device registration" + depends on BCACHE + help + Add a sysfs file /sys/fs/bcache/register_async. Writing registering + device path into this file will returns immediately and the real + registration work is handled in kernel work queue in asynchronous + way. -- cgit v1.3.1