From mboxrd@z Thu Jan 1 00:00:00 1970 From: Sachin Prabhu Subject: [PATCH 1/4] cifs: Split lanman auth from CIFS_SessSetup() Date: Fri, 2 May 2014 14:21:28 +0100 Message-ID: <1399036891-15689-2-git-send-email-sprabhu@redhat.com> References: <1399036891-15689-1-git-send-email-sprabhu@redhat.com> Cc: Simo Sorce To: linux-cifs Return-path: In-Reply-To: <1399036891-15689-1-git-send-email-sprabhu-H+wXaHxf7aLQT0dZR+AlfA@public.gmane.org> Sender: linux-cifs-owner-u79uwXL29TY76Z2rM5mHXA@public.gmane.org List-ID: 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 --- fs/cifs/sess.c | 313 ++++++++++++++++++++++++++++++++++++++++++++++++--------- 1 file changed, 268 insertions(+), 45 deletions(-) diff --git a/fs/cifs/sess.c b/fs/cifs/sess.c index e87387d..c6aa60b 100644 --- a/fs/cifs/sess.c +++ b/fs/cifs/sess.c @@ -520,6 +520,250 @@ 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; + + 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) { + mutex_unlock(&ses->server->srv_mutex); + return -ENOMEM; + } + 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; +} + +/* + * 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 +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); + } + + rc = sess_establish_session(sess_data); +out: + sess_data->result = rc; + sess_data->func = NULL; + sess_free_buffer(sess_data); +} + +#else + +static void +sess_auth_lanman(struct sess_data *sess_data) +{ + sess_data->result = -EOPNOTSUPP; + sess_data->func = NULL; +} +#endif + int CIFS_SessSetup(const unsigned int xid, struct cifs_ses *ses, const struct nls_table *nls_cp) @@ -540,12 +784,20 @@ 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 +806,15 @@ CIFS_SessSetup(const unsigned int xid, struct cifs_ses *ses, return -EINVAL; } + switch (type) { + case LANMAN: + sess_auth_lanman(sess_data); + goto out; + 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 +830,7 @@ 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 +869,7 @@ 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); @@ -889,7 +1108,6 @@ ssetup_ntlmssp_authenticate: } if (phase == NtLmChallenge) { rc = decode_ntlmssp_challenge(bcc_ptr, blob_len, ses); - /* now goto beginning for ntlmssp authenticate phase */ if (rc) goto ssetup_exit; } @@ -962,4 +1180,9 @@ keycp_exit: kfree(ses->ntlmssp); return rc; + +out: + rc = sess_data->result; + kfree(sess_data); + return rc; } -- 1.8.4.2