tools/testing/selftests/powerpc/security/mitigation-patching.sh

   1 #!/usr/bin/env bash
   2
   3 set -euo pipefail
   4
   5 TIMEOUT=10
   6
   7 function do_one
   8 {
   9     local mitigation="$1"
  10     local orig
  11     local start
  12     local now
  13
  14     orig=$(cat "$mitigation")
  15
  16     start=$(date +%s)
  17     now=$start
  18
  19     while [[ $((now-start)) -lt "$TIMEOUT" ]]
  20     do
  21         echo 0 > "$mitigation"
  22         echo 1 > "$mitigation"
  23
  24         now=$(date +%s)
  25     done
  26
  27     echo "$orig" > "$mitigation"
  28 }
  29
  30 rc=0
  31 cd /sys/kernel/debug/powerpc || rc=1
  32 if [[ "$rc" -ne 0 ]]; then
  33     echo "Error: couldn't cd to /sys/kernel/debug/powerpc" >&2
  34     exit 1
  35 fi
  36
  37 tainted=$(cat /proc/sys/kernel/tainted)
  38 if [[ "$tainted" -ne 0 ]]; then
  39     echo "Warning: kernel already tainted! ($tainted)" >&2
  40 fi
  41
  42 mitigations="barrier_nospec stf_barrier count_cache_flush rfi_flush entry_flush uaccess_flush"
  43
  44 for m in $mitigations
  45 do
  46     if [[ -f /sys/kernel/debug/powerpc/$m ]]
  47     then
  48         do_one "$m" &
  49     fi
  50 done
  51
  52 echo "Spawned threads enabling/disabling mitigations ..."
  53
  54 if stress-ng > /dev/null 2>&1; then
  55     stress="stress-ng"
  56 elif stress > /dev/null 2>&1; then
  57     stress="stress"
  58 else
  59     stress=""
  60 fi
  61
  62 if [[ -n "$stress" ]]; then
  63     "$stress" -m "$(nproc)" -t "$TIMEOUT" &
  64     echo "Spawned VM stressors ..."
  65 fi
  66
  67 echo "Waiting for timeout ..."
  68 wait
  69
  70 orig_tainted=$tainted
  71 tainted=$(cat /proc/sys/kernel/tainted)
  72 if [[ "$tainted" != "$orig_tainted" ]]; then
  73     echo "Error: kernel newly tainted, before ($orig_tainted) after ($tainted)" >&2
  74     exit 1
  75 fi
  76
  77 echo "OK"
  78 exit 0