On Thu, 17 Feb 2011 00:59:44 -0600
Shirish Pargaonkar <shirishpargaonkar@xxxxxxxxx> wrote:
> 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);
That should work if the ! always turns 0x0 into 0x1. How certain of that
are you?
--
Jeff Layton <jlayton@xxxxxxxxxx>
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