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ext/standard: notice on long passwords in bcrypt #23076

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ext/standard: notice on long passwords in bcrypt #23076

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dc867d9
ext/standard: notice on long passwords in bcrypt
Sjord Aug 5, 2026
2cb7458
Fix test title
Sjord Aug 5, 2026
0451a9f
Add password longer than 72 chars to test
Sjord Aug 6, 2026
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4 changes: 4 additions & 0 deletions ext/standard/password.c
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Original file line number Diff line number Diff line change
Expand Up @@ -184,6 +184,10 @@ static zend_string* php_password_bcrypt_hash(const zend_string *password, zend_a
return NULL;
}

if (ZSTR_LEN(password) > 72) {
zend_error(E_NOTICE, "Passwords longer than 72 characters are truncated by bcrypt");
}

if (options && (zcost = zend_hash_str_find(options, "cost", sizeof("cost")-1)) != NULL) {
cost = zval_get_long(zcost);
}
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25 changes: 25 additions & 0 deletions ext/standard/tests/password/bcrypt_72_char_limit.phpt
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Original file line number Diff line number Diff line change
@@ -0,0 +1,25 @@
--TEST--
Test 72 character limit of bcrypt
--FILE--
<?php
$long_pass = str_repeat('a', 71);

$hash = password_hash($long_pass . 'a', PASSWORD_BCRYPT, array("cost" => 4));
var_dump(password_verify($long_pass . 'a', $hash));
var_dump(password_verify($long_pass . 'b', $hash));

$hash = password_hash($long_pass . 'aa', PASSWORD_BCRYPT, array("cost" => 4));
var_dump(password_verify($long_pass . 'aa', $hash));

echo "This is the unexpected behavior we warn about: password is different but password_verify returns true.\n";
var_dump(password_verify($long_pass . 'ab', $hash));

?>
--EXPECTF--
bool(true)
bool(false)

Notice: Passwords longer than 72 characters are truncated by bcrypt in %s on line %d
bool(true)
This is the unexpected behavior we warn about: password is different but password_verify returns true.
bool(true)
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