On Wed, Feb 16, 2011 at 7:52 PM, Jeff Layton <jlayton@xxxxxxxxxx> wrote:
> On Wed, 16 Feb 2011 18:05:28 -0600
> shirishpargaonkar@xxxxxxxxx wrote:
>
>> From: Shirish Pargaonkar <shirishpargaonkar@xxxxxxxxx>
>>
>>
>> Fix lanman (lm) authentication code.
>>
>> Change lm response length back to 24 from 16.
>> Add code to add odd parity bit to each of the eight bytes of a DES key.
>>
>>
>> Signed-off-by: Shirish Pargaonkar <shirishpargaonkar@xxxxxxxxx>
>> ---
>> fs/cifs/sess.c | 8 ++++----
>> fs/cifs/smbdes.c | 5 ++++-
>> 2 files changed, 8 insertions(+), 5 deletions(-)
>>
>> diff --git a/fs/cifs/sess.c b/fs/cifs/sess.c
>> index 1adc962..1676570 100644
>> --- a/fs/cifs/sess.c
>> +++ b/fs/cifs/sess.c
>> @@ -656,13 +656,13 @@ ssetup_ntlmssp_authenticate:
>>
>> if (type == LANMAN) {
>> #ifdef CONFIG_CIFS_WEAK_PW_HASH
>> - char lnm_session_key[CIFS_SESS_KEY_SIZE];
>> + char lnm_session_key[CIFS_AUTH_RESP_SIZE];
>>
>> pSMB->req.hdr.Flags2 &= ~SMBFLG2_UNICODE;
>>
>> /* no capabilities flags in old lanman negotiation */
>>
>> - pSMB->old_req.PasswordLength = cpu_to_le16(CIFS_SESS_KEY_SIZE);
>> + pSMB->old_req.PasswordLength = cpu_to_le16(CIFS_AUTH_RESP_SIZE);
>>
>> /* Calculate hash with password and copy into bcc_ptr.
>> * Encryption Key (stored as in cryptkey) gets used if the
>> @@ -675,8 +675,8 @@ ssetup_ntlmssp_authenticate:
>> true : false, lnm_session_key);
>>
>> ses->flags |= CIFS_SES_LANMAN;
>> - memcpy(bcc_ptr, (char *)lnm_session_key, CIFS_SESS_KEY_SIZE);
>> - bcc_ptr += CIFS_SESS_KEY_SIZE;
>> + memcpy(bcc_ptr, (char *)lnm_session_key, CIFS_AUTH_RESP_SIZE);
>> + bcc_ptr += CIFS_AUTH_RESP_SIZE;
>>
>> /* can not sign if LANMAN negotiated so no need
>> to calculate signing key? but what if server
>> diff --git a/fs/cifs/smbdes.c b/fs/cifs/smbdes.c
>> index 0472148..0ab5def 100644
>> --- a/fs/cifs/smbdes.c
>> +++ b/fs/cifs/smbdes.c
>> @@ -312,8 +312,11 @@ str_to_key(unsigned char *str, unsigned char *key)
>> key[5] = ((str[4] & 0x1F) << 2) | (str[5] >> 6);
>> key[6] = ((str[5] & 0x3F) << 1) | (str[6] >> 7);
>> key[7] = str[6] & 0x7F;
>> - for (i = 0; i < 8; i++)
>> + for (i = 0; i < 8; i++) {
>> key[i] = (key[i] << 1);
>> + if (~(hweight8(key[i]) & 1))
>> + key[i] |= 0x1; /* add odd parity bit */
>> + }
>
> This doesn't look right:
>
> hweight8 will return an unsigned int. You & that with 1, so you'll
> either get 0x1 (for odd number of bits) or 0x0 (for even). Then take
> the one's compliment of that and you'll either have 0xfffffffe (odd) or
> 0xffffffff (even), both of which will return true.
>
> I think you'll need to do this differently -- perhaps something like
> this which also has the advantage of avoiding the if statement:
>
> /* set the odd parity bit */
> key[i] |= (~(hweight8(key[i]) & 1)) & 1;
This should work
key[i] |= !(hweight8(key[i]) % 2);
>
> ...though be sure to step through the bitwise logic by hand to make
> sure I've got it right. There may also be more efficient ways to do
> this that I don't see right offhand.
>
> --
> Jeff Layton <jlayton@xxxxxxxxxx>
>
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