Fix issue where params which are sub-strings of other params caused problems e.g. ro and cros_secure

scripts/image_signing/ensure_secure_kernelparams.sh

Index: scripts/image_signing/ensure_secure_kernelparams.sh
diff --git a/scripts/image_signing/ensure_secure_kernelparams.sh b/scripts/image_signing/ensure_secure_kernelparams.sh
index 1d159d4c6c1d42ce85ebc7f01647e42a28155620..e1577495cad87430914c70b29e9c88bc3819dc37 100755
--- a/scripts/image_signing/ensure_secure_kernelparams.sh
+++ b/scripts/image_signing/ensure_secure_kernelparams.sh
@@ -32,6 +32,10 @@ dmparams_mangle_sha1() {
     echo "$1" | sed 's/sha1 [0-9a-fA-F]*/sha1 MAGIC_HASH/'
 }
 
+escape_regexmetas() {

[gauravsh, 2011/02/18 00:11:56]

add comment saying this escapes non-alphanumeric characters.

+    echo "$1" | sed 's/\([^a-zA-Z0-9]\)/\\\1/g'
+}
+
 usage() {
     echo "Usage $PROG image [config]"
 }
@@ -93,13 +97,15 @@ main() {
         else
             # Remove matched params as we go. If all goes well, kparams_nodm
             # will be nothing left but whitespace by the end.
-            kparams_nodm=${kparams_nodm/$param/}
+            param=$(escape_regexmetas "$param")
+            kparams_nodm=$(echo "$kparams_nodm" | sed "s/\b$param\b//")
         fi
     done
 
     # Check-off each of the allowed-but-optional params that were present.
     for param in ${optional_kparams[@]}; do :

[gauravsh, 2011/02/18 00:11:56]

remove unnecessary colon at the end

-        kparams_nodm=${kparams_nodm/$param/}
+        param=$(escape_regexmetas "$param")
+        kparams_nodm=$(echo "$kparams_nodm" | sed "s/\b$param\b//")
     done
 
     # This section enforces the default-deny for any unexpected params