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

ID: 10518 Updated by: derick Reported By: kettler@gmx.net Old-Status: Open Status: Assigned Bug Type: mcrypt related PHP Version: 4.0.4pl1 Assigned To: derick Comments: thx, will look into this soon Previous Comments: --------------------------------------------------------------------------- [2001-04-26 18:28:36] kettler@gmx.net 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($plain)."nn"; print bin2hex($crypted)."nn"; 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); --------------------------------------------------------------------------- ATTENTION! Do NOT reply to this email! To reply, use the web interface found at http://bugs.php.net/?id=10518&edit=2