From e8117120b677937902fc3c75ba3cee97e1fa0dc1 Mon Sep 17 00:00:00 2001
From: Hung-Te Lin <hungte@chromium.org>
Date: Mon, 10 Feb 2014 17:35:34 +0800
Subject: set_gbb_flags: Check write protection status before starting to
 flash.

People trying to override GBB flags and not having write protection disabled may
corrupt whole RW section of firmware.

To avoid that, we should check write protection before starting to invoke
flashrom commands.

BUG=chromium:341242
TEST=./set_gbb_flags.sh 0x39 # Aborted on a write-protected system, as expected.
BRANCH=none

Change-Id: I6b2dcc75b87dc5ceace0d7caec62ded787b2b534
Signed-off-by: Hung-Te Lin <hungte@chromium.org>
Reviewed-on: https://chromium-review.googlesource.com/185653
Reviewed-by: Randall Spangler <rspangler@chromium.org>
Commit-Queue: Hung-Te Lin <hungte@google.com>
---
 scripts/image_signing/set_gbb_flags.sh | 27 +++++++++++++++++++++++++++
 1 file changed, 27 insertions(+)

diff --git a/scripts/image_signing/set_gbb_flags.sh b/scripts/image_signing/set_gbb_flags.sh
index e812dba3..157913aa 100755
--- a/scripts/image_signing/set_gbb_flags.sh
+++ b/scripts/image_signing/set_gbb_flags.sh
@@ -13,6 +13,7 @@ load_shflags || exit 1
 
 # DEFINE_string name default_value description flag
 DEFINE_string file "" "Path to firmware image. Default to system firmware." "f"
+DEFINE_boolean check_wp $FLAGS_TRUE "Check write protection states first." ""
 
 # Globals
 # ----------------------------------------------------------------------------
@@ -47,6 +48,24 @@ FLASHROM_COMMON_OPT="-p host"
 FLASHROM_READ_OPT="$FLASHROM_COMMON_OPT -i GBB -r"
 FLASHROM_WRITE_OPT="$FLASHROM_COMMON_OPT -i GBB --fast-verify -w"
 
+# Check write protection
+# ----------------------------------------------------------------------------
+check_write_protection() {
+  local ret=$FLAGS_TRUE
+  if ! crossystem "wpsw_boot?0"; then
+    echo "Hardware write protection must be disabled."
+    ret=$FLAGS_FALSE
+  fi
+  local wp_states="$(flashrom --wp-status 2>/dev/null | grep WP)"
+  local wp_disabled="$(echo "$wp_states" | grep "WP:.*is disabled.")"
+  local wp_zero_len="$(echo "$wp_states" | grep "WP:.*, len=0x00000000")"
+  if [ -z "$wp_disabled" -a -z "$wp_zero_len" ]; then
+    echo "Software write protection must be disabled."
+    ret=$FLAGS_FALSE
+  fi
+  return $ret
+}
+
 # Main
 # ----------------------------------------------------------------------------
 main() {
@@ -69,6 +88,14 @@ main() {
   gbb_utility -s --flags="$value" "$image_file"
 
   if [ -z "$FLAGS_file" ]; then
+    if [ "$FLAGS_check_wp" = "$FLAGS_TRUE" ]; then
+      if ! check_write_protection; then
+        echo ""
+        echo "WARNING: System GBB Flags are NOT changed!!!"
+        echo "ERROR: You must disable write protection before setting flags."
+        exit 1
+      fi
+    fi
     flashrom $FLASHROM_WRITE_OPT "$image_file"
   fi
 }
-- 
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