Bug #10518: mcrypt_generic is padding input when using cfb and ofb modes

From: kettler@gmx.net Operating system: Mandrake 7.2, Linux 2.2.19ow1 PHP version: 4.0.4pl1 PHP Bug Type: mcrypt related Bug description: mcrypt_generic is padding input when using cfb and ofb modes When encrypting using a block cipher and cfb or ofb mode the mcrypt_generic/mdecrypt_generic function still pad the input to a multiple of the underlying algorithm's block size. Input should not be padded when used with cfb or ofb mode. Script showing the bug: $key = pack("H*", "0000000000000000000000000000000000000000000000000000000000000000"); $iv = pack("H*", "00000000000000000000000000000000"); $plain = pack("H*", "0000000000000000"); $handle = mcrypt_module_open(MCRYPT_TWOFISH, "", MCRYPT_MODE_CFB, ""); mcrypt_generic_init($handle, $key, $iv); $crypted = mcrypt_generic($handle, $plain); mcrypt_generic_end($handle); print bin2hex($plain)."\n\n"; print bin2hex($crypted)."\n\n"; Proposed patch: --- mcrypt/mcrypt.c Wed Nov 22 22:40:15 2000 +++ mcrypt-sk/mcrypt.c Fri Apr 27 00:25:16 2001 @@ -498,7 +498,7 @@ convert_to_string_ex (data); /* Check blocksize */ - if (mcrypt_enc_is_block_algorithm (td) == 1) { /* It's a block algorithm */ + if (mcrypt_enc_is_block_mode (td) == 1) { /* It's a block algorithm */ block_size = mcrypt_enc_get_block_size (td); data_size = (((Z_STRLEN_PP(data) - 1) / block_size) + 1) * block_size; data_s = emalloc (data_size); @@ -539,7 +539,7 @@ convert_to_string_ex (data); /* Check blocksize */ - if (mcrypt_enc_is_block_algorithm (td) == 1) { /* It's a block algorithm */ + if (mcrypt_enc_is_block_mode (td) == 1) { /* It's a block algorithm */ block_size = mcrypt_enc_get_block_size (td); data_size = (((Z_STRLEN_PP(data) - 1) / block_size) + 1) * block_size; data_s = emalloc (data_size); -- Edit Bug report at: http://bugs.php.net/?id=10518&edit=1