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 --- scripts/gdb/vmlinux-gdb.py | 52 ++++++++++++++++++++++++++++++++++++++++++++++ 1 file changed, 52 insertions(+) create mode 100644 scripts/gdb/vmlinux-gdb.py (limited to 'scripts/gdb/vmlinux-gdb.py') diff --git a/scripts/gdb/vmlinux-gdb.py b/scripts/gdb/vmlinux-gdb.py new file mode 100644 index 000000000..d4eeed450 --- /dev/null +++ b/scripts/gdb/vmlinux-gdb.py @@ -0,0 +1,52 @@ +# +# gdb helper commands and functions for Linux kernel debugging +# +# loader module +# +# Copyright (c) Siemens AG, 2012, 2013 +# +# Authors: +# Jan Kiszka +# +# This work is licensed under the terms of the GNU GPL version 2. +# + +import os + +sys.path.insert(0, os.path.dirname(os.path.abspath(__file__)) + "/scripts/gdb") + +try: + gdb.parse_and_eval("0") + gdb.execute("", to_string=True) +except: + gdb.write("NOTE: gdb 7.2 or later required for Linux helper scripts to " + "work.\n") +else: + import linux.constants + if linux.constants.LX_CONFIG_DEBUG_INFO_REDUCED: + raise gdb.GdbError("Reduced debug information will prevent GDB " + "from having complete types.\n") + import linux.utils + import linux.symbols + import linux.modules + import linux.dmesg + import linux.tasks + import linux.config + import linux.cpus + import linux.lists + import linux.rbtree + import linux.proc + import linux.timerlist + import linux.clk + import linux.genpd + import linux.device + import linux.vfs + import linux.pgtable + import linux.radixtree + import linux.interrupts + import linux.mm + import linux.stackdepot + import linux.page_owner + import linux.slab + import linux.vmalloc + import linux.kasan -- cgit v1.3.1