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Move rate-limit check before provider pre-processing and invalidate tokens #859

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Move rate-limit check before provider pre-processing and invalidate tokens #859

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ef346c9
Move rate-limit check before provider pre-processing and invalidate t…
dknauss Mar 28, 2026
d61ec6e
Add tests for provider switch, GET bypass, and revalidation rate limi…
dknauss Mar 28, 2026
d3a48ae
Remove unused variable in resend rate-limit test
dknauss Mar 29, 2026
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17 changes: 11 additions & 6 deletions class-two-factor-core.php
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Original file line number Diff line number Diff line change
Expand Up @@ -1688,18 +1688,18 @@ public static function process_provider( $provider, $user, $is_post_request ) {
);
}

// Allow the provider to re-send codes, etc.
if ( true === $provider->pre_process_authentication( $user ) ) {
return false;
}

// If it's not a POST request, there's no processing to perform.
if ( ! $is_post_request ) {
return false;
}

// Rate limit two factor authentication attempts.
// Rate limit two factor authentication attempts, including pre-processing (e.g. resend).
if ( true === self::is_user_rate_limited( $user ) ) {
// Invalidate any provider token to prevent reuse after rate limiting.
if ( method_exists( $provider, 'delete_token' ) ) {
$provider->delete_token( $user->ID );
}

$time_delay = self::get_user_time_delay( $user );
$last_login = get_user_meta( $user->ID, self::USER_RATE_LIMIT_KEY, true );

Expand All @@ -1713,6 +1713,11 @@ public static function process_provider( $provider, $user, $is_post_request ) {
);
}

// Allow the provider to re-send codes, etc.
if ( true === $provider->pre_process_authentication( $user ) ) {
return false;
}

// Ask the provider to verify the second factor.
if ( true !== $provider->validate_authentication( $user ) ) {
// Store the last time a failed login occurred.
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129 changes: 129 additions & 0 deletions tests/class-two-factor-core.php
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Original file line number Diff line number Diff line change
Expand Up @@ -644,6 +644,135 @@ public function test_is_user_rate_limited() {
$this->assertFalse( Two_Factor_Core::is_user_rate_limited( $user ) );
}

/**
* Test that email resend requests are blocked while rate limited.
*
* @covers Two_Factor_Core::process_provider()
*/
public function test_process_provider_blocks_email_resend_while_rate_limited() {
$user = $this->get_dummy_user( array( 'Two_Factor_Email' => 'Two_Factor_Email' ) );
$provider = Two_Factor_Email::get_instance();

$provider->generate_token( $user->ID );

update_user_meta( $user->ID, Two_Factor_Core::USER_FAILED_LOGIN_ATTEMPTS_KEY, 1 );
update_user_meta( $user->ID, Two_Factor_Core::USER_RATE_LIMIT_KEY, time() );

$_REQUEST[ Two_Factor_Email::INPUT_NAME_RESEND_CODE ] = 1;

$result = Two_Factor_Core::process_provider( $provider, $user, true );

unset( $_REQUEST[ Two_Factor_Email::INPUT_NAME_RESEND_CODE ] );

$this->assertWPError( $result );
$this->assertSame( 'two_factor_too_fast', $result->get_error_code() );
$this->assertFalse( $provider->get_user_token( $user->ID ), 'Token is invalidated when rate limited' );
}

/**
* Test that rate limiting invalidates the email token on validation attempts.
*
* @covers Two_Factor_Core::process_provider()
*/
public function test_process_provider_invalidates_email_token_when_rate_limited() {
$user = $this->get_dummy_user( array( 'Two_Factor_Email' => 'Two_Factor_Email' ) );
$provider = Two_Factor_Email::get_instance();

$provider->generate_token( $user->ID );

$this->assertTrue( $provider->user_has_token( $user->ID ), 'Token exists before rate limiting' );

// Simulate a rate-limited state.
update_user_meta( $user->ID, Two_Factor_Core::USER_FAILED_LOGIN_ATTEMPTS_KEY, 3 );
update_user_meta( $user->ID, Two_Factor_Core::USER_RATE_LIMIT_KEY, time() );

$result = Two_Factor_Core::process_provider( $provider, $user, true );

$this->assertWPError( $result );
$this->assertSame( 'two_factor_too_fast', $result->get_error_code() );
$this->assertFalse( $provider->user_has_token( $user->ID ), 'Token is invalidated when rate limited' );
}

/**
* Test that switching providers while rate-limited invalidates email token.
*
* If a user fails on TOTP triggering rate limiting, then switches back
* to email, the rate-limit gate should invalidate the email token.
*
* @covers Two_Factor_Core::process_provider()
*/
public function test_process_provider_invalidates_email_token_on_provider_switch_while_rate_limited() {
$user = $this->get_dummy_user( array( 'Two_Factor_Email' => 'Two_Factor_Email' ) );
$email_provider = Two_Factor_Email::get_instance();

// Generate an email token.
$email_provider->generate_token( $user->ID );
$this->assertTrue( $email_provider->user_has_token( $user->ID ), 'Email token exists before TOTP failures' );

// Simulate rate-limited state from TOTP failures.
update_user_meta( $user->ID, Two_Factor_Core::USER_FAILED_LOGIN_ATTEMPTS_KEY, 5 );
update_user_meta( $user->ID, Two_Factor_Core::USER_RATE_LIMIT_KEY, time() );

// User switches back to email provider while rate-limited.
$result = Two_Factor_Core::process_provider( $email_provider, $user, true );

$this->assertWPError( $result );
$this->assertSame( 'two_factor_too_fast', $result->get_error_code() );
$this->assertFalse( $email_provider->user_has_token( $user->ID ), 'Email token is invalidated when rate-limited via another provider' );
}

/**
* Test that GET requests pass through without rate-limit side effects.
*
* Page reloads should not trigger rate limiting, token deletion, or
* error messages — even when the user is rate-limited.
*
* @covers Two_Factor_Core::process_provider()
*/
public function test_process_provider_get_request_bypasses_rate_limit() {
$user = $this->get_dummy_user( array( 'Two_Factor_Email' => 'Two_Factor_Email' ) );
$provider = Two_Factor_Email::get_instance();

$provider->generate_token( $user->ID );

$this->assertTrue( $provider->user_has_token( $user->ID ), 'Token exists before GET request' );

// Simulate a rate-limited state.
update_user_meta( $user->ID, Two_Factor_Core::USER_FAILED_LOGIN_ATTEMPTS_KEY, 3 );
update_user_meta( $user->ID, Two_Factor_Core::USER_RATE_LIMIT_KEY, time() );

// GET request (is_post_request = false).
$result = Two_Factor_Core::process_provider( $provider, $user, false );

$this->assertFalse( $result, 'GET request returns false, not WP_Error' );
$this->assertTrue( $provider->user_has_token( $user->ID ), 'Token survives GET request while rate-limited' );
}

/**
* Test that rate limiting applies during the revalidation flow.
*
* @covers Two_Factor_Core::process_provider()
*/
public function test_process_provider_rate_limits_revalidation() {
$user = $this->get_dummy_user( array( 'Two_Factor_Email' => 'Two_Factor_Email' ) );
$provider = Two_Factor_Email::get_instance();

$provider->generate_token( $user->ID );

$this->assertTrue( $provider->user_has_token( $user->ID ), 'Token exists before revalidation' );

// Simulate rate-limited state from prior failures.
update_user_meta( $user->ID, Two_Factor_Core::USER_FAILED_LOGIN_ATTEMPTS_KEY, 3 );
update_user_meta( $user->ID, Two_Factor_Core::USER_RATE_LIMIT_KEY, time() );

// Revalidation is also a POST through process_provider.
$result = Two_Factor_Core::process_provider( $provider, $user, true );

$this->assertWPError( $result );
$this->assertSame( 'two_factor_too_fast', $result->get_error_code() );
$this->assertFalse( $provider->user_has_token( $user->ID ), 'Token is invalidated during rate-limited revalidation' );
}

/**
* Test that the "invalid login attempts have occurred" login notice works as expected.
*
Expand Down
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