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Bug #26906 strlen returns values for non string types
Submitted: 2004-01-14 13:24 UTC Modified: 2004-01-14 14:05 UTC
Votes:1
Avg. Score:5.0 ± 0.0
Reproduced:1 of 1 (100.0%)
Same Version:1 (100.0%)
Same OS:1 (100.0%)
From: scottmacvicar at ntlworld dot com Assigned:
Status: Not a bug Package: Scripting Engine problem
PHP Version: 4CVS-2004-01-14 (stable) OS: All
Private report: No CVE-ID: None
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From: scottmacvicar at ntlworld dot com
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 [2004-01-14 13:24 UTC] scottmacvicar at ntlworld dot com 
Description:
------------
strlen will return a value for boolean types as well as a consitent value of 5 for an array.

Reproduce code:
---------------
<?php

var_dump(strlen('foo')); // 3
var_dump(strlen(true)); // 1
var_dump(strlen(false)); // 0
var_dump(strlen(array('foo', 'bar'))); // 5

?>

Expected result:
----------------
string foo = int(3)
bool true = int(-1)
bool false = int(-1)
array('foo', 'bar') = int(-1)

Actual result:
--------------
string foo = int(3)
bool true = int(1)
bool false = int(0)
array('foo', 'bar') = int(5)

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 [2004-01-14 13:25 UTC] scottmacvicar at ntlworld dot com 
Patch

diff -u zend_builtin_functions.c zend_builtin_functions.c.patched
--- zend_builtin_functions.c    2003-08-28 18:06:52.000000000 +0100
+++ zend_builtin_functions.c.patched    2004-01-14 17:46:02.000000000 +0000
@@ -260,6 +260,16 @@
        if (ZEND_NUM_ARGS() != 1 || zend_get_parameters_ex(1, &str) == FAILURE) {
                ZEND_WRONG_PARAM_COUNT();
        }
+       switch((*str)->type) {
+               case IS_LONG:
+               case IS_DOUBLE:
+               case IS_STRING:
+                       break;
+               default:
+                       zend_error(E_WARNING, "Variable passed to strlen() is not a string or number");
+                       RETURN_LONG(-1);
+                       break;
+       }
        convert_to_string_ex(str);
        RETVAL_LONG((*str)->value.str.len);
 }
 [2004-01-14 13:52 UTC] eru@php.net 
As PHP is a typeless language, this behaviour is expected. Please take a look at this extended version of your script:

var_dump((string)'foo', strlen('foo')); // 3
var_dump((string)true, strlen(true)); // 1
var_dump((string)false, strlen(false)); // 0
var_dump((string)array('foo', 'bar'), strlen(array('foo', 'bar'))); // 5
 [2004-01-14 14:05 UTC] scottmacvicar at ntlworld dot com 
Indeed PHP is a typeless language and the convert_to_string_ex(str); attempts to convert an invalid value to a string.

A similar change to this was made in PHP 5 regarding array_merge which would cause a Warning if a non array type was used as a parameter and I feel that a likewise change would be of benefit.
 
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