You cannot select more than 25 topics Topics must start with a letter or number, can include dashes ('-') and can be up to 35 characters long.

164 lines
5.1 KiB
PHTML

<?php
namespace WPMailSMTP\Helpers;
/**
* Class for encryption functionality.
*
* @since 2.5.0
*
* @link https://www.php.net/manual/en/intro.sodium.php
*/
class Crypto {
/**
* Get a secret key for encrypt/decrypt.
*
* @since 2.5.0
*
* @param bool $create Should the key be created, if it does not exist yet.
*
* @return string|bool
*/
public static function get_secret_key( $create = false ) {
if ( defined( 'WPMS_CRYPTO_KEY' ) ) {
return WPMS_CRYPTO_KEY;
}
$secret_key = apply_filters( 'wp_mail_smtp_helpers_crypto_get_secret_key', get_option( 'wp_mail_smtp_mail_key' ) );
// If we already have the secret, send it back.
if ( false !== $secret_key ) {
return base64_decode( $secret_key ); // phpcs:ignore WordPress.PHP.DiscouragedPHPFunctions.obfuscation_base64_decode
}
if ( $create ) {
// We don't have a secret, so let's generate one.
try {
$secret_key = sodium_crypto_secretbox_keygen(); // phpcs:ignore PHPCompatibility.FunctionUse.NewFunctions.sodium_crypto_secretbox_keygenFound
} catch ( \Exception $e ) {
$secret_key = wp_generate_password( SODIUM_CRYPTO_SECRETBOX_KEYBYTES ); // phpcs:ignore PHPCompatibility.Constants.NewConstants.sodium_crypto_secretbox_keybytesFound
}
add_option( 'wp_mail_smtp_mail_key', base64_encode( $secret_key ) ); // phpcs:ignore WordPress.PHP.DiscouragedPHPFunctions.obfuscation_base64_encode
return $secret_key;
}
return false;
}
/**
* Encrypt a message.
*
* @since 2.5.0
*
* @param string $message Message to encrypt.
* @param string $key Encryption key.
*
* @return string
* @throws \Exception The exception object.
*/
public static function encrypt( $message, $key = '' ) {
if ( apply_filters( 'wp_mail_smtp_helpers_crypto_stop', false ) ) {
return $message;
}
// Create a nonce for this operation. It will be stored and recovered in the message itself.
// phpcs:ignore PHPCompatibility.FunctionUse.NewFunctions.random_bytesFound, PHPCompatibility.Constants.NewConstants.sodium_crypto_secretbox_noncebytesFound
$nonce = random_bytes( SODIUM_CRYPTO_SECRETBOX_NONCEBYTES );
if ( empty( $key ) ) {
$key = self::get_secret_key( true );
}
// Encrypt message and combine with nonce.
$cipher = base64_encode( // phpcs:ignore WordPress.PHP.DiscouragedPHPFunctions.obfuscation_base64_encode
$nonce .
sodium_crypto_secretbox( // phpcs:ignore PHPCompatibility.FunctionUse.NewFunctions.sodium_crypto_secretboxFound
$message,
$nonce,
$key
)
);
try {
sodium_memzero( $message ); // phpcs:ignore PHPCompatibility.FunctionUse.NewFunctions.sodium_memzeroFound
sodium_memzero( $key ); // phpcs:ignore PHPCompatibility.FunctionUse.NewFunctions.sodium_memzeroFound
} catch ( \Exception $e ) {
return $cipher;
}
return $cipher;
}
/**
* Decrypt a message.
* Returns encrypted message on any failure and the decrypted message on success.
*
* @since 2.5.0
*
* @param string $encrypted Encrypted message.
* @param string $key Encryption key.
*
* @return string
* @throws \Exception The exception object.
*/
public static function decrypt( $encrypted, $key = '' ) { // phpcs:ignore Generic.Metrics.CyclomaticComplexity.TooHigh
if ( apply_filters( 'wp_mail_smtp_helpers_crypto_stop', false ) ) {
return $encrypted;
}
// Unpack base64 message.
$decoded = base64_decode( $encrypted ); // phpcs:ignore WordPress.PHP.DiscouragedPHPFunctions.obfuscation_base64_decode
if ( false === $decoded ) {
return $encrypted;
}
// Include polyfill if mbstring PHP extension is not enabled.
if ( ! function_exists( 'mb_strlen' ) || ! function_exists( 'mb_substr' ) ) {
Helpers::include_mbstring_polyfill();
}
// phpcs:ignore PHPCompatibility.Constants.NewConstants.sodium_crypto_secretbox_noncebytesFound, PHPCompatibility.Constants.NewConstants.sodium_crypto_secretbox_macbytesFound
if ( mb_strlen( $decoded, '8bit' ) < ( SODIUM_CRYPTO_SECRETBOX_NONCEBYTES + SODIUM_CRYPTO_SECRETBOX_MACBYTES ) ) {
return $encrypted;
}
// Pull nonce and ciphertext out of unpacked message.
$nonce = mb_substr( $decoded, 0, SODIUM_CRYPTO_SECRETBOX_NONCEBYTES, '8bit' ); // phpcs:ignore PHPCompatibility.Constants.NewConstants.sodium_crypto_secretbox_noncebytesFound
$ciphertext = mb_substr( $decoded, SODIUM_CRYPTO_SECRETBOX_NONCEBYTES, null, '8bit' ); // phpcs:ignore PHPCompatibility.Constants.NewConstants.sodium_crypto_secretbox_noncebytesFound
$key = empty( $key ) ? self::get_secret_key() : $key;
if ( empty( $key ) ) {
return $encrypted;
}
// Decrypt it.
$message = sodium_crypto_secretbox_open( // phpcs:ignore PHPCompatibility.FunctionUse.NewFunctions.sodium_crypto_secretbox_openFound
$ciphertext,
$nonce,
$key
);
// Check for decryption failures.
if ( false === $message ) {
return $encrypted;
}
try {
sodium_memzero( $ciphertext ); // phpcs:ignore PHPCompatibility.FunctionUse.NewFunctions.sodium_memzeroFound
sodium_memzero( $key ); // phpcs:ignore PHPCompatibility.FunctionUse.NewFunctions.sodium_memzeroFound
} catch ( \Exception $e ) {
return $message;
}
return $message;
}
}