On Mon, 2014-04-28 at 21:16 -0500, Shirish Pargaonkar wrote:
> On Mon, Apr 28, 2014 at 9:12 AM, Sachin Prabhu <sprabhu@xxxxxxxxxx> wrote:
> > In preparation for splitting CIFS_SessSetup() into smaller more
> > manageable chunks, we first add helper functions.
> >
> > We then proceed to split out lanman auth out of CIFS_SessSetup()
> >
> > Signed-off-by: Sachin Prabhu <sprabhu@xxxxxxxxxx>
> > ---
> > fs/cifs/sess.c | 303 ++++++++++++++++++++++++++++++++++++++++++++++++---------
> > 1 file changed, 259 insertions(+), 44 deletions(-)
> >
> > diff --git a/fs/cifs/sess.c b/fs/cifs/sess.c
> > index e87387d..8481631 100644
> > --- a/fs/cifs/sess.c
> > +++ b/fs/cifs/sess.c
> > @@ -520,6 +520,237 @@ select_sectype(struct TCP_Server_Info *server, enum securityEnum requested)
> > }
> > }
> >
> > +struct sess_data {
> > + unsigned int xid;
> > + struct cifs_ses *ses;
> > + struct nls_table *nls_cp;
> > + void (*func) (struct sess_data *);
> > + int result;
> > +
> > + /* we will send the SMB in three pieces:
> > + * a fixed length beginning part, an optional
> > + * SPNEGO blob (which can be zero length), and a
> > + * last part which will include the strings
> > + * and rest of bcc area. This allows us to avoid
> > + * a large buffer 17K allocation
> > + */
> > + struct kvec iov[3];
> > + int buf0_type;
> > +};
> > +
> > +static int
> > +sess_alloc_buffer(struct sess_data *sess_data, int wct)
> > +{
> > + int rc;
> > + struct cifs_ses *ses = sess_data->ses;
> > + struct smb_hdr *smb_buf;
> > +
> > + rc = small_smb_init_no_tc(SMB_COM_SESSION_SETUP_ANDX, wct, ses,
> > + (void **)&smb_buf);
> > +
> > + if (rc)
> > + return rc;
> > +
> > + sess_data->iov[0].iov_base = (char *)smb_buf;
> > + sess_data->iov[0].iov_len = be32_to_cpu(smb_buf->smb_buf_length) + 4;
> > + /*
> > + * * This variable will be used to clear the buffer
> > + * * allocated above in case of any error in the calling function.
> > + * */
> > + sess_data->buf0_type = CIFS_SMALL_BUFFER;
> > +
> > + /* 2000 big enough to fit max user, domain, NOS name etc. */
> > + sess_data->iov[2].iov_base = kmalloc(2000, GFP_KERNEL);
> > + if (!sess_data->iov[2].iov_base) {
> > + rc = -ENOMEM;
> > + goto out_free_smb_buf;
> > + }
> > +
> > + return 0;
> > +
> > +out_free_smb_buf:
> > + kfree(smb_buf);
> > + sess_data->iov[0].iov_base = NULL;
> > + sess_data->iov[0].iov_len = 0;
> > + sess_data->buf0_type = CIFS_NO_BUFFER;
> > + return rc;
> > +}
> > +
> > +static int
> > +sess_free_buffer(struct sess_data *sess_data)
> > +{
> > +
> > + if (sess_data->buf0_type == CIFS_SMALL_BUFFER) {
> > + cifs_dbg(FYI, "%s: freeing small buf %p\n", __func__,
> > + sess_data->iov[0].iov_base);
> > + cifs_small_buf_release(sess_data->iov[0].iov_base);
> > + } else if (sess_data->buf0_type == CIFS_LARGE_BUFFER) {
> > + cifs_dbg(FYI, "%s: freeing small buf %p\n", __func__,
> > + sess_data->iov[0].iov_base);
> > + cifs_buf_release(sess_data->iov[0].iov_base);
> > + }
> > +
> > + kfree(sess_data->iov[2].iov_base);
> > +
> > + return 0;
> > +}
> > +
> > +static int
> > +sess_establish_session(struct sess_data *sess_data)
> > +{
> > + struct cifs_ses *ses = sess_data->ses;
> > +
> > + if (!sess_data->result) {
> > + mutex_lock(&ses->server->srv_mutex);
> > + if (!ses->server->session_estab) {
> > + if (ses->server->sign) {
> > + ses->server->session_key.response =
> > + kmemdup(ses->auth_key.response,
> > + ses->auth_key.len, GFP_KERNEL);
> > + if (!ses->server->session_key.response) {
> > + sess_data->result = -ENOMEM;
> > + mutex_unlock(&ses->server->srv_mutex);
> > + return sess_data->result;
> > + }
> > + ses->server->session_key.len =
> > + ses->auth_key.len;
> > + }
> > + ses->server->sequence_number = 0x2;
> > + ses->server->session_estab = true;
> > + }
> > + mutex_unlock(&ses->server->srv_mutex);
> > +
> > + cifs_dbg(FYI, "CIFS session established successfully\n");
> > + spin_lock(&GlobalMid_Lock);
> > + ses->status = CifsGood;
> > + ses->need_reconnect = false;
> > + spin_unlock(&GlobalMid_Lock);
> > + }
> > +
> > + return 0;
> > +}
> > +
> > +static int
> > +sess_sendreceive(struct sess_data *sess_data)
> > +{
> > + int rc;
> > + struct smb_hdr *smb_buf = (struct smb_hdr *) sess_data->iov[0].iov_base;
> > + __u16 count;
> > +
> > + count = sess_data->iov[1].iov_len + sess_data->iov[2].iov_len;
> > + smb_buf->smb_buf_length =
> > + cpu_to_be32(be32_to_cpu(smb_buf->smb_buf_length) + count);
> > + put_bcc(count, smb_buf);
> > +
> > + rc = SendReceive2(sess_data->xid, sess_data->ses,
> > + sess_data->iov, 3 /* num_iovecs */,
> > + &sess_data->buf0_type,
> > + CIFS_LOG_ERROR);
> > +
> > + return rc;
> > +}
> > +
> > +#ifdef CONFIG_CIFS_WEAK_PW_HASH
> > +static void
> > +sess_auth_lanman(struct sess_data *sess_data)
> > +{
> > + int rc = 0;
> > + struct smb_hdr *smb_buf;
> > + SESSION_SETUP_ANDX *pSMB;
> > + char *bcc_ptr;
> > + struct cifs_ses *ses = sess_data->ses;
> > + char lnm_session_key[CIFS_AUTH_RESP_SIZE];
> > + __u32 capabilities;
> > + __u16 bytes_remaining;
> > +
> > + /* lanman 2 style sessionsetup */
> > + /* wct = 10 */
> > + rc = sess_alloc_buffer(sess_data, 10);
> > + if (rc)
> > + goto out;
> > +
> > + pSMB = (SESSION_SETUP_ANDX *)sess_data->iov[0].iov_base;
> > + bcc_ptr = sess_data->iov[2].iov_base;
> > + capabilities = cifs_ssetup_hdr(ses, pSMB);
> > +
> > + pSMB->req.hdr.Flags2 &= ~SMBFLG2_UNICODE;
> > +
> > + /* no capabilities flags in old lanman negotiation */
> > + 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
> > + * security mode bit in Negottiate Protocol response states
> > + * to use challenge/response method (i.e. Password bit is 1).
> > + */
> > + rc = calc_lanman_hash(ses->password, ses->server->cryptkey,
> > + ses->server->sec_mode & SECMODE_PW_ENCRYPT ?
> > + true : false, lnm_session_key);
> > +
> > + 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
> > + * changed to do higher than lanman dialect and
> > + * we reconnected would we ever calc signing_key?
> > + */
> > +
> > + cifs_dbg(FYI, "Negotiating LANMAN setting up strings\n");
> > + /* Unicode not allowed for LANMAN dialects */
> > + ascii_ssetup_strings(&bcc_ptr, ses, sess_data->nls_cp);
> > +
> > + sess_data->iov[2].iov_len = (long) bcc_ptr -
> > + (long) sess_data->iov[2].iov_base;
> > +
> > + rc = sess_sendreceive(sess_data);
> > + if (rc)
> > + goto out;
> > +
> > + pSMB = (SESSION_SETUP_ANDX *)sess_data->iov[0].iov_base;
> > + smb_buf = (struct smb_hdr *)sess_data->iov[0].iov_base;
> > +
> > + /* lanman response has a word count of 3 */
> > + if (smb_buf->WordCount != 3) {
> > + rc = -EIO;
> > + cifs_dbg(VFS, "bad word count %d\n", smb_buf->WordCount);
> > + goto out;
> > + }
> > +
> > + if (le16_to_cpu(pSMB->resp.Action) & GUEST_LOGIN)
> > + cifs_dbg(FYI, "Guest login\n"); /* BB mark SesInfo struct? */
> > +
> > + ses->Suid = smb_buf->Uid; /* UID left in wire format (le) */
> > + cifs_dbg(FYI, "UID = %llu\n", ses->Suid);
> > +
> > + bytes_remaining = get_bcc(smb_buf);
> > + bcc_ptr = pByteArea(smb_buf);
> > +
> > + /* BB check if Unicode and decode strings */
> > + if (bytes_remaining == 0) {
> > + /* no string area to decode, do nothing */
> > + } else if (smb_buf->Flags2 & SMBFLG2_UNICODE) {
> > + /* unicode string area must be word-aligned */
> > + if (((unsigned long) bcc_ptr - (unsigned long) smb_buf) % 2) {
> > + ++bcc_ptr;
> > + --bytes_remaining;
> > + }
> > + decode_unicode_ssetup(&bcc_ptr, bytes_remaining, ses,
> > + sess_data->nls_cp);
> > + } else {
> > + decode_ascii_ssetup(&bcc_ptr, bytes_remaining, ses,
> > + sess_data->nls_cp);
> > + }
> > +
> > +out:
> > + sess_data->result = rc;
> > + sess_data->func = NULL;
> > + sess_free_buffer(sess_data);
> > + sess_establish_session(sess_data);
> > +}
> > +#endif
> > +
>
> I do not think you need ifdef around sess_auth_lanman().
The code will never be used if CONFIG_CIFS_WEAK_PW_HASH is not defined
and all requests to use lanman authentication will result in a
-ENOTSUPP.
Sachin Prabhu
>
> > int
> > CIFS_SessSetup(const unsigned int xid, struct cifs_ses *ses,
> > const struct nls_table *nls_cp)
> > @@ -540,12 +771,20 @@ CIFS_SessSetup(const unsigned int xid, struct cifs_ses *ses,
> > __le32 phase = NtLmNegotiate; /* NTLMSSP, if needed, is multistage */
> > u16 blob_len;
> > char *ntlmsspblob = NULL;
> > + struct sess_data *sess_data;
> >
> > if (ses == NULL) {
> > WARN(1, "%s: ses == NULL!", __func__);
> > return -EINVAL;
> > }
> >
> > + sess_data = kzalloc(sizeof(struct sess_data), GFP_KERNEL);
> > + if (!sess_data)
> > + return -ENOMEM;
> > + sess_data->xid = xid;
> > + sess_data->ses = ses;
> > + sess_data->nls_cp = (struct nls_table *) nls_cp;
> > +
> > type = select_sectype(ses->server, ses->sectype);
> > cifs_dbg(FYI, "sess setup type %d\n", type);
> > if (type == Unspecified) {
> > @@ -554,6 +793,24 @@ CIFS_SessSetup(const unsigned int xid, struct cifs_ses *ses,
> > return -EINVAL;
> > }
> >
> > + switch (type) {
> > + case LANMAN:
> > + /* LANMAN and plaintext are less secure and off by default.
> > + * So we make this explicitly be turned on in kconfig (in the
> > + * build) and turned on at runtime (changed from the default)
> > + * in proc/fs/cifs or via mount parm. Unfortunately this is
> > + * needed for old Win (e.g. Win95), some obscure NAS and OS/2 */
> > +#ifdef CONFIG_CIFS_WEAK_PW_HASH
> > + sess_auth_lanman(sess_data);
> > + return sess_data->result;
> > +#else
> > + return -EOPNOTSUPP;
> > +#endif
> > + default:
> > + /* Continue with the rest of the function */
> > + break;
> > + }
> > +
> > if (type == RawNTLMSSP) {
> > /* if memory allocation is successful, caller of this function
> > * frees it.
> > @@ -569,17 +826,7 @@ ssetup_ntlmssp_authenticate:
> > if (phase == NtLmChallenge)
> > phase = NtLmAuthenticate; /* if ntlmssp, now final phase */
> >
> > - if (type == LANMAN) {
> > -#ifndef CONFIG_CIFS_WEAK_PW_HASH
> > - /* LANMAN and plaintext are less secure and off by default.
> > - So we make this explicitly be turned on in kconfig (in the
> > - build) and turned on at runtime (changed from the default)
> > - in proc/fs/cifs or via mount parm. Unfortunately this is
> > - needed for old Win (e.g. Win95), some obscure NAS and OS/2 */
> > - return -EOPNOTSUPP;
> > -#endif
> > - wct = 10; /* lanman 2 style sessionsetup */
> > - } else if ((type == NTLM) || (type == NTLMv2)) {
> > + if ((type == NTLM) || (type == NTLMv2)) {
> > /* For NTLMv2 failures eventually may need to retry NTLM */
> > wct = 13; /* old style NTLM sessionsetup */
> > } else /* same size: negotiate or auth, NTLMSSP or extended security */
> > @@ -618,39 +865,7 @@ ssetup_ntlmssp_authenticate:
> > iov[1].iov_base = NULL;
> > iov[1].iov_len = 0;
> >
> > - if (type == LANMAN) {
> > -#ifdef CONFIG_CIFS_WEAK_PW_HASH
> > - 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_AUTH_RESP_SIZE);
> > -
> > - /* Calculate hash with password and copy into bcc_ptr.
> > - * Encryption Key (stored as in cryptkey) gets used if the
> > - * security mode bit in Negottiate Protocol response states
> > - * to use challenge/response method (i.e. Password bit is 1).
> > - */
> > -
> > - rc = calc_lanman_hash(ses->password, ses->server->cryptkey,
> > - ses->server->sec_mode & SECMODE_PW_ENCRYPT ?
> > - true : false, lnm_session_key);
> > -
> > - 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
> > - changed to do higher than lanman dialect and
> > - we reconnected would we ever calc signing_key? */
> > -
> > - cifs_dbg(FYI, "Negotiating LANMAN setting up strings\n");
> > - /* Unicode not allowed for LANMAN dialects */
> > - ascii_ssetup_strings(&bcc_ptr, ses, nls_cp);
> > -#endif
> > - } else if (type == NTLM) {
> > + if (type == NTLM) {
> > pSMB->req_no_secext.Capabilities = cpu_to_le32(capabilities);
> > pSMB->req_no_secext.CaseInsensitivePasswordLength =
> > cpu_to_le16(CIFS_AUTH_RESP_SIZE);
> > --
> > 1.8.4.2
> >
> > --
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