cifs: break out lanman NEGOTIATE handling into separate function

...this also gets rid of some #ifdef ugliness too.
Signed-off-by: Jeff Layton <jlayton@redhat.com>
Acked-by: Pavel Shilovsky <piastry@etersoft.ru>
Signed-off-by: Steve French <sfrench@us.ibm.com>

fs/cifs/cifssmb.c

@@ -417,88 +417,22 @@ decode_ext_sec_blob(struct TCP_Server_Info *server, NEGOTIATE_RSP *pSMBr)
 	return 0;
 }
 
-int
-CIFSSMBNegotiate(const unsigned int xid, struct cifs_ses *ses)
-{
-	NEGOTIATE_REQ *pSMB;
-	NEGOTIATE_RSP *pSMBr;
-	int rc = 0;
-	int bytes_returned;
-	int i;
-	struct TCP_Server_Info *server = ses->server;
-	u16 count;
-	unsigned int secFlags;
-
-	if (!server) {
-		WARN(1, "%s: server is NULL!\n", __func__);
-		return -EIO;
-	}
-
-	rc = smb_init(SMB_COM_NEGOTIATE, 0, NULL /* no tcon yet */ ,
-		      (void **) &pSMB, (void **) &pSMBr);
-	if (rc)
-		return rc;
-
-	/* if any of auth flags (ie not sign or seal) are overriden use them */
-	if (ses->overrideSecFlg & (~(CIFSSEC_MUST_SIGN | CIFSSEC_MUST_SEAL)))
-		secFlags = ses->overrideSecFlg;  /* BB FIXME fix sign flags? */
-	else /* if override flags set only sign/seal OR them with global auth */
-		secFlags = global_secflags | ses->overrideSecFlg;
-
-	cifs_dbg(FYI, "secFlags 0x%x\n", secFlags);
-
-	pSMB->hdr.Mid = get_next_mid(server);
-	pSMB->hdr.Flags2 |= (SMBFLG2_UNICODE | SMBFLG2_ERR_STATUS);
-
-	if ((secFlags & CIFSSEC_MUST_KRB5) == CIFSSEC_MUST_KRB5)
-		pSMB->hdr.Flags2 |= SMBFLG2_EXT_SEC;
-	else if ((secFlags & CIFSSEC_AUTH_MASK) == CIFSSEC_MAY_KRB5) {
-		cifs_dbg(FYI, "Kerberos only mechanism, enable extended security\n");
-		pSMB->hdr.Flags2 |= SMBFLG2_EXT_SEC;
-	} else if ((secFlags & CIFSSEC_MUST_NTLMSSP) == CIFSSEC_MUST_NTLMSSP)
-		pSMB->hdr.Flags2 |= SMBFLG2_EXT_SEC;
-	else if ((secFlags & CIFSSEC_AUTH_MASK) == CIFSSEC_MAY_NTLMSSP) {
-		cifs_dbg(FYI, "NTLMSSP only mechanism, enable extended security\n");
-		pSMB->hdr.Flags2 |= SMBFLG2_EXT_SEC;
-	}
-
-	count = 0;
-	for (i = 0; i < CIFS_NUM_PROT; i++) {
-		strncpy(pSMB->DialectsArray+count, protocols[i].name, 16);
-		count += strlen(protocols[i].name) + 1;
-		/* null at end of source and target buffers anyway */
-	}
-	inc_rfc1001_len(pSMB, count);
-	pSMB->ByteCount = cpu_to_le16(count);
-
-	rc = SendReceive(xid, ses, (struct smb_hdr *) pSMB,
-			 (struct smb_hdr *) pSMBr, &bytes_returned, 0);
-	if (rc != 0)
-		goto neg_err_exit;
-
-	server->dialect = le16_to_cpu(pSMBr->DialectIndex);
-	cifs_dbg(FYI, "Dialect: %d\n", server->dialect);
-	/* Check wct = 1 error case */
-	if ((pSMBr->hdr.WordCount < 13) || (server->dialect == BAD_PROT)) {
-		/* core returns wct = 1, but we do not ask for core - otherwise
-		small wct just comes when dialect index is -1 indicating we
-		could not negotiate a common dialect */
-		rc = -EOPNOTSUPP;
-		goto neg_err_exit;
 #ifdef CONFIG_CIFS_WEAK_PW_HASH
-	} else if ((pSMBr->hdr.WordCount == 13)
-			&& ((server->dialect == LANMAN_PROT)
-				|| (server->dialect == LANMAN2_PROT))) {
+static int
+decode_lanman_negprot_rsp(struct TCP_Server_Info *server, NEGOTIATE_RSP *pSMBr,
+			  unsigned int secFlags)
+{
 	__s16 tmp;
 	struct lanman_neg_rsp *rsp = (struct lanman_neg_rsp *)pSMBr;
 
-		if ((secFlags & CIFSSEC_MAY_LANMAN) ||
-			(secFlags & CIFSSEC_MAY_PLNTXT))
+	if (server->dialect != LANMAN_PROT && server->dialect != LANMAN2_PROT)
+		return -EOPNOTSUPP;
+
+	if ((secFlags & CIFSSEC_MAY_LANMAN) || (secFlags & CIFSSEC_MAY_PLNTXT))
 		server->secType = LANMAN;
 	else {
 		cifs_dbg(VFS, "mount failed weak security disabled in /proc/fs/cifs/SecurityFlags\n");
-			rc = -EOPNOTSUPP;
-			goto neg_err_exit;
+		return -EOPNOTSUPP;
 	}
 	server->sec_mode = le16_to_cpu(rsp->SecurityMode);
 	server->maxReq = min_t(unsigned int,
@@ -554,29 +488,106 @@ CIFSSMBNegotiate(const unsigned int xid, struct cifs_ses *ses)
 
 	if (rsp->EncryptionKeyLength ==
 			cpu_to_le16(CIFS_CRYPTO_KEY_SIZE)) {
-			memcpy(ses->server->cryptkey, rsp->EncryptionKey,
+		memcpy(server->cryptkey, rsp->EncryptionKey,
 			CIFS_CRYPTO_KEY_SIZE);
 	} else if (server->sec_mode & SECMODE_PW_ENCRYPT) {
-			rc = -EIO; /* need cryptkey unless plain text */
-			goto neg_err_exit;
+		return -EIO; /* need cryptkey unless plain text */
 	}
 
 	cifs_dbg(FYI, "LANMAN negotiated\n");
-		/* we will not end up setting signing flags - as no signing
-		was in LANMAN and server did not return the flags on */
-		goto signing_check;
-#else /* weak security disabled */
-	} else if (pSMBr->hdr.WordCount == 13) {
+	return 0;
+}
+#else
+static inline int
+decode_lanman_negprot_rsp(struct TCP_Server_Info *server, NEGOTIATE_RSP *pSMBr,
+			  unsigned int secFlags)
+{
 	cifs_dbg(VFS, "mount failed, cifs module not built with CIFS_WEAK_PW_HASH support\n");
+	return -EOPNOTSUPP;
+}
+#endif
+
+int
+CIFSSMBNegotiate(const unsigned int xid, struct cifs_ses *ses)
+{
+	NEGOTIATE_REQ *pSMB;
+	NEGOTIATE_RSP *pSMBr;
+	int rc = 0;
+	int bytes_returned;
+	int i;
+	struct TCP_Server_Info *server = ses->server;
+	u16 count;
+	unsigned int secFlags;
+
+	if (!server) {
+		WARN(1, "%s: server is NULL!\n", __func__);
+		return -EIO;
+	}
+
+	rc = smb_init(SMB_COM_NEGOTIATE, 0, NULL /* no tcon yet */ ,
+		      (void **) &pSMB, (void **) &pSMBr);
+	if (rc)
+		return rc;
+
+	/* if any of auth flags (ie not sign or seal) are overriden use them */
+	if (ses->overrideSecFlg & (~(CIFSSEC_MUST_SIGN | CIFSSEC_MUST_SEAL)))
+		secFlags = ses->overrideSecFlg;  /* BB FIXME fix sign flags? */
+	else /* if override flags set only sign/seal OR them with global auth */
+		secFlags = global_secflags | ses->overrideSecFlg;
+
+	cifs_dbg(FYI, "secFlags 0x%x\n", secFlags);
+
+	pSMB->hdr.Mid = get_next_mid(server);
+	pSMB->hdr.Flags2 |= (SMBFLG2_UNICODE | SMBFLG2_ERR_STATUS);
+
+	if ((secFlags & CIFSSEC_MUST_KRB5) == CIFSSEC_MUST_KRB5)
+		pSMB->hdr.Flags2 |= SMBFLG2_EXT_SEC;
+	else if ((secFlags & CIFSSEC_AUTH_MASK) == CIFSSEC_MAY_KRB5) {
+		cifs_dbg(FYI, "Kerberos only mechanism, enable extended security\n");
+		pSMB->hdr.Flags2 |= SMBFLG2_EXT_SEC;
+	} else if ((secFlags & CIFSSEC_MUST_NTLMSSP) == CIFSSEC_MUST_NTLMSSP)
+		pSMB->hdr.Flags2 |= SMBFLG2_EXT_SEC;
+	else if ((secFlags & CIFSSEC_AUTH_MASK) == CIFSSEC_MAY_NTLMSSP) {
+		cifs_dbg(FYI, "NTLMSSP only mechanism, enable extended security\n");
+		pSMB->hdr.Flags2 |= SMBFLG2_EXT_SEC;
+	}
+
+	count = 0;
+	for (i = 0; i < CIFS_NUM_PROT; i++) {
+		strncpy(pSMB->DialectsArray+count, protocols[i].name, 16);
+		count += strlen(protocols[i].name) + 1;
+		/* null at end of source and target buffers anyway */
+	}
+	inc_rfc1001_len(pSMB, count);
+	pSMB->ByteCount = cpu_to_le16(count);
+
+	rc = SendReceive(xid, ses, (struct smb_hdr *) pSMB,
+			 (struct smb_hdr *) pSMBr, &bytes_returned, 0);
+	if (rc != 0)
+		goto neg_err_exit;
+
+	server->dialect = le16_to_cpu(pSMBr->DialectIndex);
+	cifs_dbg(FYI, "Dialect: %d\n", server->dialect);
+	/* Check wct = 1 error case */
+	if ((pSMBr->hdr.WordCount < 13) || (server->dialect == BAD_PROT)) {
+		/* core returns wct = 1, but we do not ask for core - otherwise
+		small wct just comes when dialect index is -1 indicating we
+		could not negotiate a common dialect */
 		rc = -EOPNOTSUPP;
-#endif /* WEAK_PW_HASH */
+		goto neg_err_exit;
+	} else if (pSMBr->hdr.WordCount == 13) {
+		rc = decode_lanman_negprot_rsp(server, pSMBr, secFlags);
+		if (!rc)
+			goto signing_check;
+		else
 			goto neg_err_exit;
 	} else if (pSMBr->hdr.WordCount != 17) {
 		/* unknown wct */
 		rc = -EOPNOTSUPP;
 		goto neg_err_exit;
 	}
-	/* else wct == 17 NTLM */
+	/* else wct == 17, NTLM or better */
+
 	server->sec_mode = pSMBr->SecurityMode;
 	if ((server->sec_mode & SECMODE_USER) == 0)
 		cifs_dbg(FYI, "share mode security\n");
@@ -634,9 +645,7 @@ CIFSSMBNegotiate(const unsigned int xid, struct cifs_ses *ses)
 	if (rc)
 		goto neg_err_exit;
 
-#ifdef CONFIG_CIFS_WEAK_PW_HASH
 signing_check:
-#endif
 	if ((secFlags & CIFSSEC_MAY_SIGN) == 0) {
 		/* MUST_SIGN already includes the MAY_SIGN FLAG
 		   so if this is zero it means that signing is disabled */