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wp_secrets_memzero › WordPress Function

Seit7.2.0
Veraltetn/v
› wp_secrets_memzero ( $value )
Parameter:
  • (string) $value The value to clear, by reference.
    Erforderlich: Ja
Definiert in:
Codex:

Best-effort clearing of a plaintext value from memory.

This is hygiene, not a guarantee. PHP strings are reference-counted and often shared by copy-on-write; sodium_memzero() can only scrub the bytes of a string it exclusively owns; if another reference to the same value exists elsewhere, PHP forces a private copy before zeroing rather than corrupting the shared buffer, and that other reference is left completely untouched. Call this on every plaintext local as soon as it is no longer needed, and do not keep incidental copies around. Under sodium_compat, core's documented fallback when the libsodium extension is unavailable, this scrubs nothing. A userland polyfill cannot reach a PHP string's underlying memory at all. Overwriting the local binding is the only thing available in that case, and it removes the live reference from this scope without touching the memory the string used to occupy.


Ähnliche Funktionen: _wp_secrets_get, _wp_secrets_set, _wp_secrets_delete, _wp_secrets_get_key_manager, _wp_secrets_get_provider

Quellcode 

function wp_secrets_memzero( &$value ): void {
	if ( ! is_string( $value ) ) {
		return;
	}

	if ( function_exists( 'sodium_memzero' ) ) {
		try {
			/*
			 * sodium_memzero() is called through a true reference alias, not
			 * directly on $value, so that a static analyzer's stub for
			 * sodium_memzero() (whose own by-ref parameter is documented as
			 * becoming null) is evaluated against a local variable rather than
			 * against this function's own by-ref parameter. The alias is not a
			 * copy: `=&` shares the identical underlying storage, so this still
			 * zeroes the real buffer the caller holds.
			 */
			$alias =& $value;
			sodium_memzero( $alias );
		} catch ( \Throwable $e ) {
			// A value this function doesn't exclusively own (a shared,
			// copy-on-write buffer) can legitimately refuse. The unconditional
			// reassignment below still runs regardless of what happened here.
			unset( $e );
		}
	}

	// Reached on every path, including sodium_memzero() success (it leaves the
	// variable null, not an empty string) so callers see one consistent contract.
	$value = '';
}