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/jbd2/Kconfig | 34 ++++++++++++++++++++++++++++++++++ 1 file changed, 34 insertions(+) create mode 100644 fs/jbd2/Kconfig (limited to 'fs/jbd2/Kconfig') diff --git a/fs/jbd2/Kconfig b/fs/jbd2/Kconfig new file mode 100644 index 000000000..9c19e1512 --- /dev/null +++ b/fs/jbd2/Kconfig @@ -0,0 +1,34 @@ +# SPDX-License-Identifier: GPL-2.0-only +config JBD2 + tristate + select CRC32 + help + This is a generic journaling layer for block devices that support + both 32-bit and 64-bit block numbers. It is currently used by + the ext4 and OCFS2 filesystems, but it could also be used to add + journal support to other file systems or block devices such + as RAID or LVM. + + If you are using ext4 or OCFS2, you need to say Y here. + If you are not using ext4 or OCFS2 then you will + probably want to say N. + + To compile this device as a module, choose M here. The module will be + called jbd2. If you are compiling ext4 or OCFS2 into the kernel, + you cannot compile this code as a module. + +config JBD2_DEBUG + bool "JBD2 (ext4) debugging support" + depends on JBD2 + help + If you are using the ext4 journaled file system (or + potentially any other filesystem/device using JBD2), this option + allows you to enable debugging output while the system is running, + in order to help track down any problems you are having. + By default, the debugging output will be turned off. + + If you select Y here, then you will be able to turn on debugging + with "echo N > /sys/module/jbd2/parameters/jbd2_debug", where N is a + number between 1 and 5. The higher the number, the more debugging + output is generated. To turn debugging off again, do + "echo 0 > /sys/module/jbd2/parameters/jbd2_debug". -- cgit v1.3.1