Bail after 10 unsuccessful tries

tools/pki/cert.sh

@@ -129,11 +129,18 @@ choose_root_cert() {
 
     echo -en "\nYour choice: " >&2
     read root_cert_choice
-    while [ "${root_certs[$root_cert_choice]}" == "" ]; do
+    local choice_counter=0
+    while [ $choice_counter -lt 10 ] && [ "${root_certs[$root_cert_choice]}" == "" ]; do
         logError "Invalid choice, please enter a valid number."
         echo -en "\nYour choice: " >&2
         read root_cert_choice
+        choice_counter=$((choice_counter + 1))
     done
+    if [ $choice_counter -ge 10 ]; then
+        logError "Too many failures."
+        cleanup "$1"
+        exit 1
+    fi
     echo "${root_certs[$root_cert_choice]}"
 }