[CIFS] NTLMSSP reenabled after move from connect.c to sess.c

The NTLMSSP code was removed from fs/cifs/connect.c and merged
(75% smaller, cleaner) into fs/cifs/sess.c

As with the old code it requires that cifs be built with
CONFIG_CIFS_EXPERIMENTAL, the /proc/fs/cifs/Experimental flag
must be set to 2, and mount must turn on extended security
(e.g. with sec=krb5).

Although NTLMSSP encapsulated in SPNEGO is not enabled yet,
"raw" ntlmssp is common and useful in some cases since it
offers more complete security negotiation, and is the
default way of negotiating security for many Windows systems.
SPNEGO encapsulated NTLMSSP will be able to reuse the same
code.

Signed-off-by: Steve French <sfrench@us.ibm.com>

2 files changed, 251 insertions, 4 deletions

diff --git a/fs/cifs/CHANGES b/fs/cifs/CHANGES
index 43f2e0d061f6..f20c4069c220 100644
--- a/fs/cifs/CHANGES
+++ b/fs/cifs/CHANGES
@@ -8,7 +8,8 @@ accurately mark string length before allocating memory (which may help the
 rare cases where a UTF-8 string is much larger than the UCS2 string that
 we converted from).  Fix endianness of the vcnum field used during
 session setup to distinguish multiple mounts to same server from different
-userids.
+userids. Raw NTLMSSP fixed (it requires /proc/fs/cifs/experimental
+flag to be set to 2, and mount must enable krb5 to turn on extended security).
  
 Version 1.57
 ------------
diff --git a/fs/cifs/sess.c b/fs/cifs/sess.c
index b2bdc2a33833..e68744e169b3 100644
--- a/fs/cifs/sess.c
+++ b/fs/cifs/sess.c
@@ -378,6 +378,186 @@ static int decode_ascii_ssetup(char **pbcc_area, int bleft,
         return rc;
 }
 
+static int decode_ntlmssp_challenge(char *bcc_ptr, int blob_len,
+                                    struct cifsSesInfo *ses)
+{
+        CHALLENGE_MESSAGE *pblob = (CHALLENGE_MESSAGE *)bcc_ptr;
+
+        if (blob_len < sizeof(CHALLENGE_MESSAGE)) {
+                cERROR(1, ("challenge blob len %d too small", blob_len));
+                return -EINVAL;
+        }
+
+        if (memcmp(pblob->Signature, "NTLMSSP", 8)) {
+                cERROR(1, ("blob signature incorrect %s", pblob->Signature));
+                return -EINVAL;
+        }
+        if (pblob->MessageType != NtLmChallenge) {
+                cERROR(1, ("Incorrect message type %d", pblob->MessageType));
+                return -EINVAL;
+        }
+
+        memcpy(ses->server->cryptKey, pblob->Challenge, CIFS_CRYPTO_KEY_SIZE);
+        /* BB we could decode pblob->NegotiateFlags; some may be useful */
+        /* In particular we can examine sign flags */
+        /* BB spec says that if AvId field of MsvAvTimestamp is populated then
+                we must set the MIC field of the AUTHENTICATE_MESSAGE */
+
+        return 0;
+}
+
+#ifdef CONFIG_CIFS_EXPERIMENTAL
+/* BB Move to ntlmssp.c eventually */
+
+/* We do not malloc the blob, it is passed in pbuffer, because
+   it is fixed size, and small, making this approach cleaner */
+static void build_ntlmssp_negotiate_blob(unsigned char *pbuffer,
+                                         struct cifsSesInfo *ses)
+{
+        NEGOTIATE_MESSAGE *sec_blob = (NEGOTIATE_MESSAGE *)pbuffer;
+        __u32 flags;
+
+        memcpy(sec_blob->Signature, NTLMSSP_SIGNATURE, 8);
+        sec_blob->MessageType = NtLmNegotiate;
+
+        /* BB is NTLMV2 session security format easier to use here? */
+        flags = NTLMSSP_NEGOTIATE_56 |  NTLMSSP_REQUEST_TARGET |
+                NTLMSSP_NEGOTIATE_128 | NTLMSSP_NEGOTIATE_UNICODE |
+                NTLMSSP_NEGOTIATE_NT_ONLY | NTLMSSP_NEGOTIATE_NTLM;
+        if (ses->server->secMode &
+           (SECMODE_SIGN_REQUIRED | SECMODE_SIGN_ENABLED))
+                flags |= NTLMSSP_NEGOTIATE_SIGN;
+        if (ses->server->secMode & SECMODE_SIGN_REQUIRED)
+                flags |= NTLMSSP_NEGOTIATE_ALWAYS_SIGN;
+
+        sec_blob->NegotiateFlags |= cpu_to_le32(flags);
+
+        sec_blob->WorkstationName.BufferOffset = 0;
+        sec_blob->WorkstationName.Length = 0;
+        sec_blob->WorkstationName.MaximumLength = 0;
+
+        /* Domain name is sent on the Challenge not Negotiate NTLMSSP request */
+        sec_blob->DomainName.BufferOffset = 0;
+        sec_blob->DomainName.Length = 0;
+        sec_blob->DomainName.MaximumLength = 0;
+}
+
+/* We do not malloc the blob, it is passed in pbuffer, because its
+   maximum possible size is fixed and small, making this approach cleaner.
+   This function returns the length of the data in the blob */
+static int build_ntlmssp_auth_blob(unsigned char *pbuffer,
+                                   struct cifsSesInfo *ses,
+                                   const struct nls_table *nls_cp, int first)
+{
+        AUTHENTICATE_MESSAGE *sec_blob = (AUTHENTICATE_MESSAGE *)pbuffer;
+        __u32 flags;
+        unsigned char *tmp;
+        char ntlm_session_key[CIFS_SESS_KEY_SIZE];
+
+        memcpy(sec_blob->Signature, NTLMSSP_SIGNATURE, 8);
+        sec_blob->MessageType = NtLmAuthenticate;
+
+        flags = NTLMSSP_NEGOTIATE_56 |
+                NTLMSSP_REQUEST_TARGET | NTLMSSP_NEGOTIATE_TARGET_INFO |
+                NTLMSSP_NEGOTIATE_128 | NTLMSSP_NEGOTIATE_UNICODE |
+                NTLMSSP_NEGOTIATE_NT_ONLY | NTLMSSP_NEGOTIATE_NTLM;
+        if (ses->server->secMode &
+           (SECMODE_SIGN_REQUIRED | SECMODE_SIGN_ENABLED))
+                flags |= NTLMSSP_NEGOTIATE_SIGN;
+        if (ses->server->secMode & SECMODE_SIGN_REQUIRED)
+                flags |= NTLMSSP_NEGOTIATE_ALWAYS_SIGN;
+
+        tmp = pbuffer + sizeof(AUTHENTICATE_MESSAGE);
+        sec_blob->NegotiateFlags |= cpu_to_le32(flags);
+
+        sec_blob->LmChallengeResponse.BufferOffset =
+                                cpu_to_le32(sizeof(AUTHENTICATE_MESSAGE));
+        sec_blob->LmChallengeResponse.Length = 0;
+        sec_blob->LmChallengeResponse.MaximumLength = 0;
+
+        /* calculate session key,  BB what about adding similar ntlmv2 path? */
+        SMBNTencrypt(ses->password, ses->server->cryptKey, ntlm_session_key);
+        if (first)
+                cifs_calculate_mac_key(&ses->server->mac_signing_key,
+                                       ntlm_session_key, ses->password);
+
+        memcpy(tmp, ntlm_session_key, CIFS_SESS_KEY_SIZE);
+        sec_blob->NtChallengeResponse.BufferOffset = cpu_to_le32(tmp - pbuffer);
+        sec_blob->NtChallengeResponse.Length = cpu_to_le16(CIFS_SESS_KEY_SIZE);
+        sec_blob->NtChallengeResponse.MaximumLength =
+                                cpu_to_le16(CIFS_SESS_KEY_SIZE);
+
+        tmp += CIFS_SESS_KEY_SIZE;
+
+        if (ses->domainName == NULL) {
+                sec_blob->DomainName.BufferOffset = cpu_to_le32(tmp - pbuffer);
+                sec_blob->DomainName.Length = 0;
+                sec_blob->DomainName.MaximumLength = 0;
+                tmp += 2;
+        } else {
+                int len;
+                len = cifs_strtoUCS((__le16 *)tmp, ses->domainName,
+                                    MAX_USERNAME_SIZE, nls_cp);
+                len *= 2; /* unicode is 2 bytes each */
+                len += 2; /* trailing null */
+                sec_blob->DomainName.BufferOffset = cpu_to_le32(tmp - pbuffer);
+                sec_blob->DomainName.Length = cpu_to_le16(len);
+                sec_blob->DomainName.MaximumLength = cpu_to_le16(len);
+                tmp += len;
+        }
+
+        if (ses->userName == NULL) {
+                sec_blob->UserName.BufferOffset = cpu_to_le32(tmp - pbuffer);
+                sec_blob->UserName.Length = 0;
+                sec_blob->UserName.MaximumLength = 0;
+                tmp += 2;
+        } else {
+                int len;
+                len = cifs_strtoUCS((__le16 *)tmp, ses->userName,
+                                    MAX_USERNAME_SIZE, nls_cp);
+                len *= 2; /* unicode is 2 bytes each */
+                len += 2; /* trailing null */
+                sec_blob->UserName.BufferOffset = cpu_to_le32(tmp - pbuffer);
+                sec_blob->UserName.Length = cpu_to_le16(len);
+                sec_blob->UserName.MaximumLength = cpu_to_le16(len);
+                tmp += len;
+        }
+
+        sec_blob->WorkstationName.BufferOffset = cpu_to_le32(tmp - pbuffer);
+        sec_blob->WorkstationName.Length = 0;
+        sec_blob->WorkstationName.MaximumLength = 0;
+        tmp += 2;
+
+        sec_blob->SessionKey.BufferOffset = cpu_to_le32(tmp - pbuffer);
+        sec_blob->SessionKey.Length = 0;
+        sec_blob->SessionKey.MaximumLength = 0;
+        return tmp - pbuffer;
+}
+
+
+static void setup_ntlmssp_neg_req(SESSION_SETUP_ANDX *pSMB,
+                                 struct cifsSesInfo *ses)
+{
+        build_ntlmssp_negotiate_blob(&pSMB->req.SecurityBlob[0], ses);
+        pSMB->req.SecurityBlobLength = cpu_to_le16(sizeof(NEGOTIATE_MESSAGE));
+
+        return;
+}
+
+static int setup_ntlmssp_auth_req(SESSION_SETUP_ANDX *pSMB,
+                                  struct cifsSesInfo *ses,
+                                  const struct nls_table *nls, int first_time)
+{
+        int bloblen;
+
+        bloblen = build_ntlmssp_auth_blob(&pSMB->req.SecurityBlob[0], ses, nls,
+                                          first_time);
+        pSMB->req.SecurityBlobLength = cpu_to_le16(bloblen);
+
+        return bloblen;
+}
+#endif
+
 int
 CIFS_SessSetup(unsigned int xid, struct cifsSesInfo *ses, int first_time,
                 const struct nls_table *nls_cp)
@@ -396,6 +576,7 @@ CIFS_SessSetup(unsigned int xid, struct cifsSesInfo *ses, int first_time,
         __u16 action;
         int bytes_remaining;
         struct key *spnego_key = NULL;
+        __le32 phase = NtLmNegotiate; /* NTLMSSP, if needed, is multistage */
 
         if (ses == NULL)
                 return -EINVAL;
@@ -403,6 +584,10 @@ CIFS_SessSetup(unsigned int xid, struct cifsSesInfo *ses, int first_time,
         type = ses->server->secType;
 
         cFYI(1, ("sess setup type %d", type));
+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.
@@ -616,9 +801,49 @@ CIFS_SessSetup(unsigned int xid, struct cifsSesInfo *ses, int first_time,
                 goto ssetup_exit;
 #endif /* CONFIG_CIFS_UPCALL */
         } else {
+#ifdef CONFIG_CIFS_EXPERIMENTAL
+                if ((experimEnabled > 1) && (type == RawNTLMSSP)) {
+                        if ((pSMB->req.hdr.Flags2 & SMBFLG2_UNICODE) == 0) {
+                                cERROR(1, ("NTLMSSP requires Unicode support"));
+                                rc = -ENOSYS;
+                                goto ssetup_exit;
+                        }
+
+                        cFYI(1, ("ntlmssp session setup phase %d", phase));
+                        pSMB->req.hdr.Flags2 |= SMBFLG2_EXT_SEC;
+                        capabilities |= CAP_EXTENDED_SECURITY;
+                        pSMB->req.Capabilities |= cpu_to_le32(capabilities);
+                        if (phase == NtLmNegotiate) {
+                                setup_ntlmssp_neg_req(pSMB, ses);
+                                iov[1].iov_len = sizeof(NEGOTIATE_MESSAGE);
+                        } else if (phase == NtLmAuthenticate) {
+                                int blob_len;
+                                blob_len = setup_ntlmssp_auth_req(pSMB, ses,
+                                                                  nls_cp,
+                                                                  first_time);
+                                iov[1].iov_len = blob_len;
+                        } else {
+                                cERROR(1, ("invalid phase %d", phase));
+                                rc = -ENOSYS;
+                                goto ssetup_exit;
+                        }
+                        iov[1].iov_base = &pSMB->req.SecurityBlob[0];
+                        /* unicode strings must be word aligned */
+                        if ((iov[0].iov_len + iov[1].iov_len) % 2) {
+                                *bcc_ptr = 0;
+                                bcc_ptr++;
+                        }
+                        unicode_oslm_strings(&bcc_ptr, nls_cp);
+                } else {
+                        cERROR(1, ("secType %d not supported!", type));
+                        rc = -ENOSYS;
+                        goto ssetup_exit;
+                }
+#else
                 cERROR(1, ("secType %d not supported!", type));
                 rc = -ENOSYS;
                 goto ssetup_exit;
+#endif
         }
 
         iov[2].iov_base = str_area;
@@ -634,12 +859,23 @@ CIFS_SessSetup(unsigned int xid, struct cifsSesInfo *ses, int first_time,
         /* SMB request buf freed in SendReceive2 */
 
         cFYI(1, ("ssetup rc from sendrecv2 is %d", rc));
-        if (rc)
-                goto ssetup_exit;
 
         pSMB = (SESSION_SETUP_ANDX *)iov[0].iov_base;
         smb_buf = (struct smb_hdr *)iov[0].iov_base;
 
+        if ((type == RawNTLMSSP) && (smb_buf->Status.CifsError ==
+                        cpu_to_le32(NT_STATUS_MORE_PROCESSING_REQUIRED))) {
+                if (phase != NtLmNegotiate) {
+                        cERROR(1, ("Unexpected more processing error"));
+                        goto ssetup_exit;
+                }
+                /* NTLMSSP Negotiate sent now processing challenge (response) */
+                phase = NtLmChallenge; /* process ntlmssp challenge */
+                rc = 0; /* MORE_PROC rc is not an error here, but expected */
+        }
+        if (rc)
+                goto ssetup_exit;
+
         if ((smb_buf->WordCount != 3) && (smb_buf->WordCount != 4)) {
                 rc = -EIO;
                 cERROR(1, ("bad word count %d", smb_buf->WordCount));
@@ -658,12 +894,18 @@ CIFS_SessSetup(unsigned int xid, struct cifsSesInfo *ses, int first_time,
         if (smb_buf->WordCount == 4) {
                 __u16 blob_len;
                 blob_len = le16_to_cpu(pSMB->resp.SecurityBlobLength);
-                bcc_ptr += blob_len;
                 if (blob_len > bytes_remaining) {
                         cERROR(1, ("bad security blob length %d", blob_len));
                         rc = -EINVAL;
                         goto ssetup_exit;
                 }
+                if (phase == NtLmChallenge) {
+                        rc = decode_ntlmssp_challenge(bcc_ptr, blob_len, ses);
+                        /* now goto beginning for ntlmssp authenticate phase */
+                        if (rc)
+                                goto ssetup_exit;
+                }
+                bcc_ptr += blob_len;
                 bytes_remaining -= blob_len;
         }
 
@@ -692,5 +934,9 @@ ssetup_exit:
         } else if (resp_buf_type == CIFS_LARGE_BUFFER)
                 cifs_buf_release(iov[0].iov_base);
 
+        /* if ntlmssp, and negotiate succeeded, proceed to authenticate phase */
+        if ((phase == NtLmChallenge) && (rc == 0))
+                goto ssetup_ntlmssp_authenticate;
+
         return rc;
 }