Mcrypt problem on PHP 4.3.1 / FreeBSD 5.3

[sylvian stone]

Hi,

I'm getting some strange errors that I cannot pin down:

Warning: mcrypt_generic_ init(): Iv size incorrect; supplied length: 7,
needed: 8 in......

This is strange because the data is encrypted, inserted into the
databse, then later retrieved and decrypted with the necessary hash and
ivector keys.

The data itself is decrypted OK. But the error comes up.

The error does not occur when I run the same code on another machine
running on Mac OS X.

Is this a known bug on this FreeBSD build ?

As this is for a production site, I'm just tempted to set the
error_reporting directive in php.ini to off, as this looks bad when the
error flashes up, but is actually not causing any errors.

I did change alter the initialisation function to:

@mcrypt_generic _init()

but it still displays the error regardless.

This may be a bit obscure, but has anybody else encountered a similar
problem ?

Thanks
SS.

[Steve]

Warning: mcrypt_generic_ init(): Iv size incorrect; supplied length: 7,
needed: 8 in......

Can you post a minimal example of code that produces the warning
message.

---
Steve

[sylvian stone]

OK,

I use the following settings:

$cipher = MCRYPT_GOST;
$mode = MCRYPT_MODE_ECB ;
$rand_src = MCRYPT_RAND;

I then randomly generate a hash and assign it to variable $hash, run it
through addslashes(), and use the following to encrypt:

$handle = mcrypt_module_o pen ($cipher, '', $mode, '');

if (!$handle)
die ("Couldn't locate open mcrypt module.");
$ivector =
mcrypt_create_i v(mcrypt_get_iv _size($cipher,$ mode),$rand_src );

if (mcrypt_generic _init ($handle, $hash, $ivector) == -1)
die ("Error: mcrypt failure.");

$address1 = addslashes(mcry pt_generic($han dle,$address1)) ;
$address2 = addslashes(mcry pt_generic($han dle,$address2)) ;
$address3 = addslashes(mcry pt_generic($han dle,$address3)) ;
$address4 = addslashes(mcry pt_generic($han dle,$address4)) ;
$address5 = addslashes(mcry pt_generic($han dle,$address5)) ;
$postcode = addslashes(mcry pt_generic($han dle,$postcode)) ;
$firstname = addslashes(mcry pt_generic($han dle,$firstname) );
$surname = addslashes(mcry pt_generic($han dle,$surname));
$telephone = addslashes(mcry pt_generic($han dle,$telephone) );
$em = addslashes(mcry pt_generic($han dle,$email));
$ivector = addslashes($ive ctor);
$username = addslashes($ema il);

mcrypt_generic_ deinit($handle) ;
These are inserted into the database tables, then I later decrypt with:
$site_sql="SELE CT * FROM security WHERE client_id ='$client_id' LIMIT
1";

$site_get = mysql_query($si te_sql) or die (mysql_error()) ;
while ($row = mysql_fetch_arr ay($site_get))
{
$hash_temp = stripslashes($r ow['hash']);
$iv_temp = stripslashes($r ow['iv']);
}

$site_sql="SELE CT * FROM client WHERE client_id ='$client_id' LIMIT 1";
$site_get = mysql_query($si te_sql) or die (mysql_error()) ;
while ($row = mysql_fetch_arr ay($site_get))
{
$handle = @mcrypt_module_ open ($cipher, '', $mode, '');
if (!$handle)
die ("Couldn't locate open mcrypt module.");
if (@mcrypt_generi c_init ($handle, $hash_temp, $iv_temp) == -1)
die ("Error: mcrypt failure.");
$title = $row['title'];
$firstname = trim(stripslash es(@mdecrypt_ge neric($handle,
$row['firstname'])));
$surname = trim(stripslash es(@mdecrypt_ge neric($handle,
$row['surname'])));
$address1 = trim(stripslash es(@mdecrypt_ge neric($handle,
$row['address1'])));
$address2 = trim(stripslash es(@mdecrypt_ge neric($handle,
$row['address2'])));
$address3 = trim(stripslash es(@mdecrypt_ge neric($handle,
$row['address3'])));
$address4 = trim(stripslash es(@mdecrypt_ge neric($handle,
$row['address4'])));
$address5 = trim(stripslash es(@mdecrypt_ge neric($handle,
$row['address5'])));
$postcode = trim(stripslash es(@mdecrypt_ge neric($handle,
$row['postcode'])));
$telephone = trim(stripslash es(@mdecrypt_ge neric($handle,
$row['telephone'])));
$email = trim(stripslash es(@mdecrypt_ge neric($handle,
$row['email'])));
@mcrypt_generic _deinit($handle );
}

As I said, the data is decrypted fine. But this error keeps popping
up...

Very obscure....

Thanks
SS

[Steve]

As I said, the data is decrypted fine. But this error keeps popping
up...
Suggestions:
$ivector = mcrypt_create_i v(mcrypt_get_iv _size($cipher,$ mode),$rand_src );

Break this down into two calls, and check that the size returned from
the first call is what you expect.

$ivsize = mcrypt_get_iv_s ize($cipher,$mo de);
// [ check/debug $ivsize before use ]
$ivector = mcrypt_create_i v($ivsize,$rand _src);

Use <http://www.php.net/manual/en/function.mcrypt-enc-get-iv-size.php>
instead to see if it makes a difference.

$handle = mcrypt_module_o pen($cipher, '', $mode, '');
if(!$handle) die ("Couldn't locate open mcrypt module.");
$ivsize = mcrypt_enc_get_ iv_size($handle );
// [ check/debug $ivsize before use ]
$ivector = mcrypt_create_i v($ivsize,$rand _src);

Or suppress the warning as you suggest, as it seems harmless 8-)

---
Steve

[sylvian stone]

I may just try and surpress the error.

I'm probably getting off the point here, but will the following
command:

ini_set('displa y_errors','0');

surpress ALL errors, or just some errors.

I ask, because on the code I posted above, adding a @ before the mcrypt
functions still caused the error to appear.....

[Steve]

ini_set('displa y_errors','0');

You could try turning error reporting off just before the rogue
statement and back on again immediately after:
$oldsetting = ini_set( 'error_reportin g', E_NONE );
// ...rogue statment(s) here...
ini_set( 'error_reportin g', $oldsetting );
---
Steve