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 --- arch/powerpc/boot/install.sh | 37 +++++++++++++++++++++++++++++++++++++ 1 file changed, 37 insertions(+) create mode 100755 arch/powerpc/boot/install.sh (limited to 'arch/powerpc/boot/install.sh') diff --git a/arch/powerpc/boot/install.sh b/arch/powerpc/boot/install.sh new file mode 100755 index 000000000..c3df6c27c --- /dev/null +++ b/arch/powerpc/boot/install.sh @@ -0,0 +1,37 @@ +#!/bin/sh +# +# This file is subject to the terms and conditions of the GNU General Public +# License. See the file "COPYING" in the main directory of this archive +# for more details. +# +# Copyright (C) 1995 by Linus Torvalds +# +# Blatantly stolen from in arch/i386/boot/install.sh by Dave Hansen +# +# "make install" script for ppc64 architecture +# +# Arguments: +# $1 - kernel version +# $2 - kernel image file +# $3 - kernel map file +# $4 - default install path (blank if root directory) + +set -e + +# this should work for both the pSeries zImage and the iSeries vmlinux.sm +image_name=$(basename "$2") + + +echo "Warning: '${INSTALLKERNEL}' command not available... Copying" \ + "directly to $4/$image_name-$1" >&2 + +if [ -f "$4"/"$image_name"-"$1" ]; then + mv "$4"/"$image_name"-"$1" "$4"/"$image_name"-"$1".old +fi + +if [ -f "$4"/System.map-"$1" ]; then + mv "$4"/System.map-"$1" "$4"/System-"$1".old +fi + +cat "$2" > "$4"/"$image_name"-"$1" +cp "$3" "$4"/System.map-"$1" -- cgit v1.3.1