lekoala / silverstripe-encrypt

src/EncryptedDBField.php

<?php

namespace LeKoala\Encrypt;

use Exception;
use SilverStripe\ORM\DataList;
use SilverStripe\ORM\DataObject;
use SilverStripe\Forms\FormField;
use SilverStripe\Forms\TextField;
use ParagonIE\CipherSweet\BlindIndex;
use ParagonIE\CipherSweet\CipherSweet;
use SilverStripe\ORM\Queries\SQLSelect;
use ParagonIE\CipherSweet\EncryptedField;
use SilverStripe\ORM\FieldType\DBComposite;
use SilverStripe\Model\ModelData;

/**
 * Value will be set on parent record through built in getField
 * mechanisms for composite fields
 */
class EncryptedDBField extends DBComposite
{
    use HasBaseEncryption;

    public const LARGE_INDEX_SIZE = 32;
    public const SMALL_INDEX_SIZE = 16;
    public const VALUE_SUFFIX = "Value";
    public const INDEX_SUFFIX = "BlindIndex";

    /**
     * @config
     * @var int
     */
    private static $output_size = 15;

    /**
     * @config
     * @var int
     */
    private static $domain_size = 127;

    /**
     * @var array<string,string>
     */
    private static $composite_db = [
        "Value" => "Varchar(191)",
        "BlindIndex" => 'Varchar(32)',
    ];

    /**
     * Output size is the number of bits (not bytes) of a blind index.
     * Eg: 4 for a 4 digits year
     * Note: the larger the output size, the smaller the index should be
     * @return int
     */
    public function getOutputSize()
    {
        if (array_key_exists('output_size', $this->options)) {
            $outputSize = $this->options['output_size'];
        } else {
            $outputSize = static::config()->get('output_size');
        }
        return $outputSize;
    }

    /**
     * Input domain is the set of all possible distinct inputs.
     * Eg :
     * 4 digits have 10,000 possible values (10^4).
     * The log (base 2) of 10,000 is 13.2877; you would want to always round up (so 14).
     * @return int
     */
    public function getDomainSize()
    {
        if (array_key_exists('domain_size', $this->options)) {
            $domainSize = $this->options['domain_size'];
        } else {
            $domainSize = static::config()->get('domain_size');
        }
        return $domainSize;
    }

    /**
     * @param int $default
     * @return int
     */
    public function getIndexSize($default = null)
    {
        if (array_key_exists('index_size', $this->options)) {
            return $this->options['index_size'];
        }
        if ($default !== null) {
            return $default;
        }
        return self::LARGE_INDEX_SIZE;
    }

    /**
     * @return string
     */
    public function getValueField()
    {
        return $this->getField(self::VALUE_SUFFIX);
    }

    /**
     * @param mixed $value
     * @param bool $markChanged
     * @return $this
     */
    public function setValueField($value, $markChanged = true)
    {
        return $this->setField(self::VALUE_SUFFIX, $value, $markChanged);
    }

    /**
     * @return string
     */
    public function getBlindIndexField()
    {
        return $this->getField(self::INDEX_SUFFIX);
    }

    /**
     * @param mixed $value
     * @param bool $markChanged
     * @return $this
     */
    public function setBlindIndexField($value, $markChanged = true)
    {
        return $this->setField(self::INDEX_SUFFIX, $value, $markChanged);
    }

    /**
     * @param CipherSweet $engine
     * @param bool $fashHash
     * @return EncryptedField
     */
    public function getEncryptedField($engine = null, $fashHash = null)
    {
        if ($engine === null) {
            $engine = EncryptHelper::getCipherSweet();
        }
        if ($fashHash === null) {
            $fashHash = EncryptHelper::getFashHash();
        }
        $indexSize = $this->getIndexSize(self::LARGE_INDEX_SIZE);

        //TODO: review how naming is done (see: getEncryptedRow)
        // fieldName needs to match exact db name for row rotator to work properly
        $fieldName = $this->name . self::VALUE_SUFFIX;
        $indexName = $this->name . self::INDEX_SUFFIX;

        $encryptedField = (new EncryptedField($engine, $this->tableName, $fieldName))
            ->addBlindIndex(new BlindIndex($indexName, [], $indexSize, $fashHash));
        return $encryptedField;
    }

    /**
     * Depending on your version, this may or may not be called
     * When not called, it works thanks to saveInto
     * @link https://github.com/silverstripe/silverstripe-framework/issues/8800
     * @link https://github.com/silverstripe/silverstripe-framework/pull/10913
     * @param array<string,mixed> $manipulation
     * @return void
     */
    public function writeToManipulation(array &$manipulation): void
    {
        $encryptedField = $this->getEncryptedField();
        $aad = $this->encryptionAad;
        if ($this->value) {
            $dataForStorage = $encryptedField->prepareForStorage($this->value, $aad);
            $encryptedValue = $this->prepValueForDB($dataForStorage[0]);
            /** @var array<string,string> $blindIndexes */
            $blindIndexes = $dataForStorage[1];
        } else {
            $encryptedValue = null;
            $blindIndexes = [];
        }

        $manipulation['fields'][$this->name . self::VALUE_SUFFIX] = $encryptedValue;
        foreach ($blindIndexes as $blindIndexName => $blindIndexValue) {
            $iv = $encryptedValue ? $blindIndexValue : null;
            $manipulation['fields'][$blindIndexName] = $iv;
        }
    }

    /**
     * @param SQLSelect $query
     * @return void
     */
    // public function addToQuery(&$query)
    // {
    //     parent::addToQuery($query);
    //     $query->selectField(sprintf('"%s' . self::VALUE_SUFFIX . '"', $this->name));
    //     $query->selectField(sprintf('"%s' . self::INDEX_SUFFIX . '"', $this->name));
    // }

    /**
     * Return the blind index value to search in the database
     *
     * @param string $val The unencrypted value
     * @param string $indexSuffix The blind index. Defaults to full index
     * @return string
     */
    public function getSearchValue($val, $indexSuffix = null)
    {
        if (!$this->tableName && $this->record && is_object($this->record)) {
            $this->tableName = DataObject::getSchema()->tableName(get_class($this->record));
        }
        if (!$this->tableName) {
            throw new Exception("Table name not set for search value. Please set a dataobject.");
        }
        if (!$this->name) {
            throw new Exception("Name not set for search value");
        }
        if (!$val) {
            throw new Exception("Cannot search an empty value");
        }
        if ($indexSuffix === null) {
            $indexSuffix = self::INDEX_SUFFIX;
        }
        $field = $this->getEncryptedField();
        $index = $field->getBlindIndex($val, $this->name . $indexSuffix);
        if (is_array($index)) {
            return $index['value'];
        }
        return $index;
    }

    /**
     * Return a ready to use array params for a where clause
     *
     * @param string $val The unencrypted value
     * @param string $indexSuffix The blind index. Defaults to full index
     * @return array<string,string>
     */
    public function getSearchParams($val, $indexSuffix = null)
    {
        if (!$indexSuffix) {
            $indexSuffix = self::INDEX_SUFFIX;
        }
        $searchValue = $this->getSearchValue($val, $indexSuffix);
        $blindIndexField = $this->name . $indexSuffix;
        return array($blindIndexField . ' = ?' => $searchValue);
    }

    /**
     * @param string $val The unencrypted value
     * @param string $indexSuffix The blind index. Defaults to full index
     * @param ?array $where Extra where parameters
     * @return DataList
     */
    public function fetchDataList($val, $indexSuffix = null, $where = null)
    {
        if (!$this->record || !is_object($this->record)) {
            throw new Exception("No record set for this field");
        }
        if (!$indexSuffix) {
            $indexSuffix = self::INDEX_SUFFIX;
        }
        $class = get_class($this->record);

        // A blind index can return false positives, use fetch record to make sure you get the record baased on value
        $params = $this->getSearchParams($val, $indexSuffix);
        if ($where) {
            $params = array_merge($params, $where);
        }

        /** @var DataList $list */
        $list = $class::get();
        $list = $list->where($params);
        return $list;
    }

    /**
     * @param string $val The unencrypted value
     * @param string $indexSuffix The blind index. Defaults to full index
     * @param string|array|null $ignoreID Allows to ignore one id or a list of ids
     * @param array|null Extra where parameters
     * @return DataObject|false
     */
    public function fetchRecord($val, $indexSuffix = null, $ignoreID = null, $where = null)
    {
        if (!$indexSuffix) {
            $indexSuffix = self::INDEX_SUFFIX;
        }

        if ($ignoreID) {
            if (!$where) {
                $where = [];
            }
            if (is_array($ignoreID)) {
                // Since we don't use parametrised query, make sure ids are valid ints
                $ignoreID = array_map("intval", $ignoreID);
                $ignoreID = implode(",", $ignoreID);
                $where = array_merge($where, [
                    '"ID" NOT IN (' . $ignoreID . ')'
                ]);
            } else {
                $where = array_merge($where, [
                    '"ID" != ?' => $ignoreID,
                ]);
            }
        }

        $list = $this->fetchDataList($val, $indexSuffix, $where);
        $blindIndexes = $this->getEncryptedField()->getBlindIndexObjects();
        $blindIndex = $blindIndexes[$this->name . $indexSuffix];

        // We will refetch the db object based on the field name for each record
        $name = $this->name;
        /** @var DataObject $record  */
        foreach ($list as $record) {
            /** @var EncryptedDBField $obj */
            $obj = $record->dbObject($name);
            $objValue = $obj->getValue() ?? '';
            // Value might be transformed
            if ($blindIndex->getTransformed($objValue) == $val) {
                return $record;
            }
        }
        // throw exception if there where matches but none with the right value
        if ($list->count()) {
            throw new Exception($list->count() . " records were found but none matched the right value");
        }
        return false;
    }

    public function setValue(mixed $value, null|array|ModelData $record = null, bool $markChanged = true): static
    {
        $this->setEncryptionAad($record);

        // Return early if we keep encrypted value in memory
        if (!EncryptHelper::getAutomaticDecryption()) {
            parent::setValue($value, $record, $markChanged);
            return $this;
        }

        if ($markChanged) {
            $this->isChanged = true;
        }

        // When given a dataobject, bind this field to that
        if ($record instanceof DataObject) {
            $this->bindTo($record);
        }

        // Convert an object to an array
        if ($record && $record instanceof DataObject) {
            $record = $record->getQueriedDatabaseFields();
            if (!$record) {
                throw new Exception("Could not convert record to array");
            }
        }

        // Set the table name if it was not set earlier
        if (!$this->tableName && $record) {
            $class = is_array($record) && isset($record['ClassName']) ? $record['ClassName'] : get_class($record);
            $this->tableName = DataObject::getSchema()->tableName($class);
            if (!$this->tableName) {
                throw new Exception("Could not get table name from record from " . gettype($record));
            }
        }

        // Value will store the decrypted value
        if ($value instanceof EncryptedDBField) {
            $this->value = $value->getValue();
        } elseif ($record && isset($record[$this->name . self::VALUE_SUFFIX])) {
            // In that case, the value come from the database and might be encrypted
            $encryptedValue = $record[$this->name . self::VALUE_SUFFIX];
            $this->value = $this->decryptValue($encryptedValue);
        } elseif (is_array($value)) {
            if (array_key_exists(self::VALUE_SUFFIX, $value)) {
                $this->value = $value;
            }
        } elseif (is_string($value) || !$value) {
            $this->value = $value;
        } else {
            throw new Exception("Unexcepted value of type " . gettype($value));
        }

        if (!$this->value) {
            // Forward changes otherwise old value may get restored from record
            // Can also help if manipulations are not executed properly
            $this->setValueField(null, $markChanged);

            // Make sure blind index gets nullified
            $this->setBlindIndexField(null);
        }

        return $this;
    }

    /**
     * @param array<string,mixed> $options
     * @return string
     */
    public function Nice($options = array())

The parameter $options is not used and could be removed.

    {
        return $this->getValue();
    }

    public function exists(): bool
    {
        return strlen($this->value ?? '') > 0;
    }

    /**
     * This is called by getChangedFields() to check if a field is changed
     */
    public function isChanged(): bool
    {
        return $this->isChanged;
    }

    /**
     * If we pass a DBField to the setField method, it will
     * trigger this method
     *
     * We save encrypted value on sub fields. They will be collected
     * by write() operation by prepareManipulationTable
     *
     * Currently prepareManipulationTable ignores composite fields
     * so we rely on the sub field mechanisms
     */
    public function saveInto(ModelData $model): void
    {
        $encryptedField = $this->getEncryptedField();
        $aad = $this->encryptionAad;
        if ($this->value) {
            $dataForStorage = $encryptedField->prepareForStorage($this->value, $aad);
            $encryptedValue = $this->prepValueForDB($dataForStorage[0]);
            /** @var array<string,string> $blindIndexes */
            $blindIndexes = $dataForStorage[1];
        } else {
            $encryptedValue = null;
            $blindIndexes = [];
        }

        // This cause infinite loops
        // $dataObject->setField($this->getName(), $this->value);

        // Encrypt value
        $key = $this->getName() . self::VALUE_SUFFIX;
        $model->setField($key, $encryptedValue);

        // Build blind indexes
        foreach ($blindIndexes as $blindIndexName => $blindIndexValue) {
            $iv = $this->value ? $blindIndexValue : null;
            $model->setField($blindIndexName, $iv);
        }
    }

    /**
     * @param string $title Optional. Localized title of the generated instance
     * @param array<mixed> $params
     * @return FormField
     */
    public function scaffoldFormField(?string $title = null, array $params = []): ?FormField
    {
        $field = TextField::create($this->getName());
        return $field;
    }

    /**
     * Returns the string value
     */
    public function __toString()
    {
        return (string) $this->getValue();
    }

    public function scalarValueOnly(): bool
    {
        return false;
    }
}