#!/usr/bin/env bash

# Prowler - the handy cloud security tool (copyright 2018) by Toni de la Fuente
#
# Licensed under the Apache License, Version 2.0 (the "License"); you may not
# use this file except in compliance with the License. You may obtain a copy
# of the License at http://www.apache.org/licenses/LICENSE-2.0
#
# Unless required by applicable law or agreed to in writing, software distributed
# under the License is distributed on an "AS IS" BASIS, WITHOUT WARRANTIES OR
# CONDITIONS OF ANY KIND, either express or implied. See the License for the
# specific language governing permissions and limitations under the License.
CHECK_ID_extra734="7.34"
CHECK_TITLE_extra734="[extra734] Check if S3 buckets have default encryption (SSE) enabled or use a bucket policy to enforce it (Not Scored) (Not part of CIS benchmark)"
CHECK_SCORED_extra734="NOT_SCORED"
CHECK_TYPE_extra734="EXTRA"
CHECK_ALTERNATE_check734="extra734"

extra734(){
  LIST_OF_BUCKETS=$($AWSCLI s3api list-buckets $PROFILE_OPT --query Buckets[*].Name --output text|xargs -n1)
  if [[ $LIST_OF_BUCKETS ]]; then
    for bucket in $LIST_OF_BUCKETS;do
      # query to get if has encryption enabled or not
      RESULT=$($AWSCLI s3api get-bucket-encryption $PROFILE_OPT --bucket $bucket --query ServerSideEncryptionConfiguration.Rules[].ApplyServerSideEncryptionByDefault[].SSEAlgorithm --output text 2>&1)
      if [[ $(echo "$RESULT" | grep ServerSideEncryptionConfigurationNotFoundError) ]] ; then
          textFail "Bucket $bucket does not enforce encryption!"
      elif [[ $(echo "$RESULT" | grep AccessDenied) ]] ; then
        textFail "Access Denied Trying to Get Encryption for $bucket"
      else
        TEMP_SSE_POLICY_FILE=$(mktemp -t prowler-${ACCOUNT_NUM}-${bucket}.policy.XXXXXXXXXX)
        # get bucket policy
        $AWSCLI s3api get-bucket-policy $PROFILE_OPT --bucket $bucket --output text --query Policy > $TEMP_SSE_POLICY_FILE 2> /dev/null
        # check if the S3 policy forces SSE s3:x-amz-server-side-encryption:true
        CHECK_BUCKET_SSE_POLICY_PRESENT=$(cat $TEMP_SSE_POLICY_FILE | sed -e 's/[{}]/''/g' | awk -v k="text" '{n=split($0,a,","); for (i=1; i<=n; i++) print a[i]}'| awk '/Condition/ && !skip { print } { skip = /x-amz-server-side-encryption/} '|grep \"true\")
        CHECK_BUCKET_SSE_POLICY_VALUE=$(cat $TEMP_SSE_POLICY_FILE | sed -e 's/[{}]/''/g' | awk -v k="text" '{n=split($0,a,","); for (i=1; i<=n; i++) print a[i]}'| awk '/Condition/ && !skip { print } { skip = /x-amz-server-side-encryption/} '|grep -Eo "AES256|aws:kms")

        echo "$RESULT" | while read RBUCKET SSEALG; do
          if [[ $SSEALG ]]; then
            textPass "Bucket $RBUCKET has default encryption enabled with algorithm $SSEALG"
          fi
        done
        if [[ $CHECK_BUCKET_SSE_POLICY_PRESENT && $CHECK_BUCKET_SSE_POLICY_VALUE ]]; then
          textPass "Bucket $bucket has S3 bucket policy to enforce encryption with $CHECK_BUCKET_SSE_POLICY_VALUE"
        fi

        rm -fr $TEMP_SSE_POLICY_FILE
      fi
    done

  else
    textInfo "No S3 Buckets found"
  fi
}