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 --- tools/testing/fault-injection/failcmd.sh | 232 +++++++++++++++++++++++++++++++ 1 file changed, 232 insertions(+) create mode 100755 tools/testing/fault-injection/failcmd.sh (limited to 'tools/testing/fault-injection') diff --git a/tools/testing/fault-injection/failcmd.sh b/tools/testing/fault-injection/failcmd.sh new file mode 100755 index 000000000..c4f243275 --- /dev/null +++ b/tools/testing/fault-injection/failcmd.sh @@ -0,0 +1,232 @@ +#!/bin/bash +# SPDX-License-Identifier: GPL-2.0 +# +# NAME +# failcmd.sh - run a command with injecting slab/page allocation failures +# +# SYNOPSIS +# failcmd.sh --help +# failcmd.sh [] command [arguments] +# +# DESCRIPTION +# Run command with injecting slab/page allocation failures by fault +# injection. +# +# NOTE: you need to run this script as root. +# + +usage() +{ + cat >&2 <&2 + exit 1 + fi +} + +if [ $UID != 0 ]; then + echo must be run as root >&2 + exit 1 +fi + +DEBUGFS=`mount -t debugfs | head -1 | awk '{ print $3}'` + +if [ ! -d "$DEBUGFS" ]; then + echo debugfs is not mounted >&2 + exit 1 +fi + +FAILCMD_TYPE=${FAILCMD_TYPE:-failslab} +FAULTATTR=$DEBUGFS/$FAILCMD_TYPE + +if [ ! -d $FAULTATTR ]; then + echo $FAILCMD_TYPE is not available >&2 + exit 1 +fi + +LONGOPTS=probability:,interval:,times:,space:,verbose:,task-filter: +LONGOPTS=$LONGOPTS,stacktrace-depth:,require-start:,require-end: +LONGOPTS=$LONGOPTS,reject-start:,reject-end:,oom-kill-allocating-task:,help + +if [ $FAILCMD_TYPE = failslab ]; then + LONGOPTS=$LONGOPTS,ignore-gfp-wait:,cache-filter: +elif [ $FAILCMD_TYPE = fail_page_alloc ]; then + LONGOPTS=$LONGOPTS,ignore-gfp-wait:,ignore-gfp-highmem:,min-order: +fi + +TEMP=`getopt -o p:i:t:s:v:h --long $LONGOPTS -n 'failcmd.sh' -- "$@"` + +if [ $? != 0 ]; then + usage + exit 1 +fi + +eval set -- "$TEMP" + +fault_attr_default() +{ + echo N > $FAULTATTR/task-filter + echo 0 > $FAULTATTR/probability + echo 1 > $FAULTATTR/times +} + +fault_attr_default + +oom_kill_allocating_task_saved=`cat /proc/sys/vm/oom_kill_allocating_task` + +restore_values() +{ + fault_attr_default + echo $oom_kill_allocating_task_saved \ + > /proc/sys/vm/oom_kill_allocating_task +} + +# +# Default options +# +declare -i oom_kill_allocating_task=1 +declare task_filter=Y +declare -i probability=1 +declare -i times=1 + +while true; do + case "$1" in + -p|--probability) + probability=$2 + shift 2 + ;; + -i|--interval) + echo $2 > $FAULTATTR/interval + shift 2 + ;; + -t|--times) + times=$2 + shift 2 + ;; + -s|--space) + echo $2 > $FAULTATTR/space + shift 2 + ;; + -v|--verbose) + echo $2 > $FAULTATTR/verbose + shift 2 + ;; + --task-filter) + task_filter=$2 + shift 2 + ;; + --stacktrace-depth) + echo $2 > $FAULTATTR/stacktrace-depth + shift 2 + ;; + --require-start) + exit_if_not_hex "$2" + echo $2 > $FAULTATTR/require-start + shift 2 + ;; + --require-end) + exit_if_not_hex "$2" + echo $2 > $FAULTATTR/require-end + shift 2 + ;; + --reject-start) + exit_if_not_hex "$2" + echo $2 > $FAULTATTR/reject-start + shift 2 + ;; + --reject-end) + exit_if_not_hex "$2" + echo $2 > $FAULTATTR/reject-end + shift 2 + ;; + --oom-kill-allocating-task) + oom_kill_allocating_task=$2 + shift 2 + ;; + --ignore-gfp-wait) + echo $2 > $FAULTATTR/ignore-gfp-wait + shift 2 + ;; + --cache-filter) + echo $2 > $FAULTATTR/cache_filter + shift 2 + ;; + --ignore-gfp-highmem) + echo $2 > $FAULTATTR/ignore-gfp-highmem + shift 2 + ;; + --min-order) + echo $2 > $FAULTATTR/min-order + shift 2 + ;; + -h|--help) + usage + exit 0 + shift + ;; + --) + shift + break + ;; + esac +done + +[ -z "$1" ] && exit 0 + +echo $oom_kill_allocating_task > /proc/sys/vm/oom_kill_allocating_task +echo $task_filter > $FAULTATTR/task-filter +echo $probability > $FAULTATTR/probability +echo $times > $FAULTATTR/times + +trap "restore_values" SIGINT SIGTERM EXIT + +cmd="echo 1 > /proc/self/make-it-fail && exec $@" +bash -c "$cmd" -- cgit v1.3.1