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:

$handle = mcrypt_module_open ($cipher, '', $mode, '');

if (!$handle)
die ("Couldn't locate open mcrypt module.");
$ivector =
mcrypt_create_iv(mcrypt_get_iv_size($cipher,$mode) ,$rand_src);

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

$address1 = addslashes(mcrypt_generic($handle,$address1));
$address2 = addslashes(mcrypt_generic($handle,$address2));
$address3 = addslashes(mcrypt_generic($handle,$address3));
$address4 = addslashes(mcrypt_generic($handle,$address4));
$address5 = addslashes(mcrypt_generic($handle,$address5));
$postcode = addslashes(mcrypt_generic($handle,$postcode));
$firstname = addslashes(mcrypt_generic($handle,$firstname));
$surname = addslashes(mcrypt_generic($handle,$surname));
$telephone = addslashes(mcrypt_generic($handle,$telephone));
$em = addslashes(mcrypt_generic($handle,$email));
$ivector = addslashes($ivector);
$username = addslashes($email);

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

$site_get = mysql_query($site_sql) or die (mysql_error());
while ($row = mysql_fetch_array($site_get))
{
$hash_temp = stripslashes($row['hash']);
$iv_temp = stripslashes($row['iv']);
}

$site_sql="SELECT * FROM client WHERE client_id ='$client_id' LIMIT 1";
$site_get = mysql_query($site_sql) or die (mysql_error());
while ($row = mysql_fetch_array($site_get))
{
$handle = @mcrypt_module_open ($cipher, '', $mode, '');
if (!$handle)
die ("Couldn't locate open mcrypt module.");
if (@mcrypt_generic_init ($handle, $hash_temp, $iv_temp) == -1)
die ("Error: mcrypt failure.");
$title = $row['title'];
$firstname = trim(stripslashes(@mdecrypt_generic($handle,
$row['firstname'])));
$surname = trim(stripslashes(@mdecrypt_generic($handle,
$row['surname'])));
$address1 = trim(stripslashes(@mdecrypt_generic($handle,
$row['address1'])));
$address2 = trim(stripslashes(@mdecrypt_generic($handle,
$row['address2'])));
$address3 = trim(stripslashes(@mdecrypt_generic($handle,
$row['address3'])));
$address4 = trim(stripslashes(@mdecrypt_generic($handle,
$row['address4'])));
$address5 = trim(stripslashes(@mdecrypt_generic($handle,
$row['address5'])));
$postcode = trim(stripslashes(@mdecrypt_generic($handle,
$row['postcode'])));
$telephone = trim(stripslashes(@mdecrypt_generic($handle,
$row['telephone'])));
$email = trim(stripslashes(@mdecrypt_generic($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:
$ivector = mcrypt_create_iv(mcrypt_get_iv_size($cipher,$mode) ,$rand_src);

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

$ivsize = mcrypt_get_iv_size($cipher,$mode);
// [ check/debug $ivsize before use ]
$ivector = mcrypt_create_iv($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.

$handle = mcrypt_module_open($cipher, '', $mode, '');
if(!$handle) die ("Couldn't locate open mcrypt module.");
$ivsize = mcrypt_enc_get_iv_size($handle);
// [ check/debug $ivsize before use ]
$ivector = mcrypt_create_iv($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('display_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('display_errors','0');

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