NTLM authentication and signing - Calculate auth response per smb session

Start calculation auth response within a session.  Move/Add pertinet
data structures like session key, server challenge and ntlmv2_hash in
a session structure.  We should do the calculations within a session
before copying session key and response over to server data
structures because a session setup can fail.

Only after a very first smb session succeeds, it copies/makes its
session key, session key of smb connection.  This key stays with
the smb connection throughout its life.
Signed-off-by: Shirish Pargaonkar <shirishpargaonkar@gmail.com>
Reviewed-by: Jeff Layton <jlayton@redhat.com>
Signed-off-by: Steve French <sfrench@us.ibm.com>

fs/cifs/cifsencrypt.c

@@ -458,7 +458,7 @@ static int calc_ntlmv2_hash(struct cifsSesInfo *ses,
 calc_exit_2:
 	/* BB FIXME what about bytes 24 through 40 of the signing key?
 	   compare with the NTLM example */
-	hmac_md5_final(ses->server->ntlmv2_hash, pctxt);
+	hmac_md5_final(ses->ntlmv2_hash, pctxt);
 
 	kfree(pctxt);
 	return rc;
@@ -502,14 +502,14 @@ setup_ntlmv2_rsp(struct cifsSesInfo *ses, char *resp_buf,
 	}
 	CalcNTLMv2_response(ses, resp_buf);
 
-	/* now calculate the MAC key for NTLMv2 */
-	hmac_md5_init_limK_to_64(ses->server->ntlmv2_hash, 16, &context);
+	/* now calculate the session key for NTLMv2 */
+	hmac_md5_init_limK_to_64(ses->ntlmv2_hash, 16, &context);
 	hmac_md5_update(resp_buf, 16, &context);
-	hmac_md5_final(ses->server->session_key.data.ntlmv2.key, &context);
+	hmac_md5_final(ses->auth_key.data.ntlmv2.key, &context);
 
-	memcpy(&ses->server->session_key.data.ntlmv2.resp, resp_buf,
+	memcpy(&ses->auth_key.data.ntlmv2.resp, resp_buf,
 	       sizeof(struct ntlmv2_resp));
-	ses->server->session_key.len = 16 + sizeof(struct ntlmv2_resp);
+	ses->auth_key.len = 16 + sizeof(struct ntlmv2_resp);
 
 	return 0;
 
@@ -526,8 +526,8 @@ void CalcNTLMv2_response(const struct cifsSesInfo *ses,
 {
 	struct HMACMD5Context context;
 	/* rest of v2 struct already generated */
-	memcpy(v2_session_response + 8, ses->server->cryptKey, 8);
-	hmac_md5_init_limK_to_64(ses->server->ntlmv2_hash, 16, &context);
+	memcpy(v2_session_response + 8, ses->cryptKey, 8);
+	hmac_md5_init_limK_to_64(ses->ntlmv2_hash, 16, &context);
 
 	hmac_md5_update(v2_session_response+8,
 			sizeof(struct ntlmv2_resp) - 8, &context);

fs/cifs/cifsglob.h

@@ -179,12 +179,10 @@ struct TCP_Server_Info {
 	int capabilities; /* allow selective disabling of caps by smb sess */
 	int timeAdj;  /* Adjust for difference in server time zone in sec */
 	__u16 CurrentMid;         /* multiplex id - rotating counter */
-	char cryptKey[CIFS_CRYPTO_KEY_SIZE];
 	/* 16th byte of RFC1001 workstation name is always null */
 	char workstation_RFC1001_name[RFC1001_NAME_LEN_WITH_NULL];
 	__u32 sequence_number; /* needed for CIFS PDU signature */
 	struct session_key session_key;
-	char ntlmv2_hash[16];
 	unsigned long lstrp; /* when we got last response from this server */
 	u16 dialect; /* dialect index that server chose */
 	/* extended security flavors that server supports */
@@ -192,6 +190,7 @@ struct TCP_Server_Info {
 	bool	sec_mskerberos;		/* supports legacy MS Kerberos */
 	bool	sec_kerberosu2u;	/* supports U2U Kerberos */
 	bool	sec_ntlmssp;		/* supports NTLMSSP */
+	bool session_estab; /* mark when very first sess is established */
 #ifdef CONFIG_CIFS_FSCACHE
 	struct fscache_cookie   *fscache; /* client index cache cookie */
 #endif
@@ -223,6 +222,9 @@ struct cifsSesInfo {
 	char userName[MAX_USERNAME_SIZE + 1];
 	char *domainName;
 	char *password;
+	char cryptKey[CIFS_CRYPTO_KEY_SIZE];
+	struct session_key auth_key;
+	char ntlmv2_hash[16];
 	unsigned int tilen; /* length of the target info blob */
 	unsigned char *tiblob; /* target info blob in challenge response */
 	bool need_reconnect:1; /* connection reset, uid now invalid */

fs/cifs/cifssmb.c

@@ -503,7 +503,7 @@ CIFSSMBNegotiate(unsigned int xid, struct cifsSesInfo *ses)
 
 		if (rsp->EncryptionKeyLength ==
 				cpu_to_le16(CIFS_CRYPTO_KEY_SIZE)) {
-			memcpy(server->cryptKey, rsp->EncryptionKey,
+			memcpy(ses->cryptKey, rsp->EncryptionKey,
 				CIFS_CRYPTO_KEY_SIZE);
 		} else if (server->secMode & SECMODE_PW_ENCRYPT) {
 			rc = -EIO; /* need cryptkey unless plain text */
@@ -574,7 +574,7 @@ CIFSSMBNegotiate(unsigned int xid, struct cifsSesInfo *ses)
 	server->timeAdj = (int)(__s16)le16_to_cpu(pSMBr->ServerTimeZone);
 	server->timeAdj *= 60;
 	if (pSMBr->EncryptionKeyLength == CIFS_CRYPTO_KEY_SIZE) {
-		memcpy(server->cryptKey, pSMBr->u.EncryptionKey,
+		memcpy(ses->cryptKey, pSMBr->u.EncryptionKey,
 		       CIFS_CRYPTO_KEY_SIZE);
 	} else if ((pSMBr->hdr.Flags2 & SMBFLG2_EXT_SEC)
 			&& (pSMBr->EncryptionKeyLength == 0)) {

fs/cifs/connect.c

@@ -173,6 +173,8 @@ cifs_reconnect(struct TCP_Server_Info *server)
 		sock_release(server->ssocket);
 		server->ssocket = NULL;
 	}
+	server->sequence_number = 0;
+	server->session_estab = false;
 
 	spin_lock(&GlobalMid_Lock);
 	list_for_each(tmp, &server->pending_mid_q) {
@@ -205,7 +207,6 @@ cifs_reconnect(struct TCP_Server_Info *server)
 			spin_lock(&GlobalMid_Lock);
 			if (server->tcpStatus != CifsExiting)
 				server->tcpStatus = CifsGood;
-			server->sequence_number = 0;
 			spin_unlock(&GlobalMid_Lock);
 	/*		atomic_set(&server->inFlight,0);*/
 			wake_up(&server->response_q);
@@ -1631,6 +1632,7 @@ cifs_get_tcp_session(struct smb_vol *volume_info)
 		volume_info->source_rfc1001_name, RFC1001_NAME_LEN_WITH_NULL);
 	memcpy(tcp_ses->server_RFC1001_name,
 		volume_info->target_rfc1001_name, RFC1001_NAME_LEN_WITH_NULL);
+	tcp_ses->session_estab = false;
 	tcp_ses->sequence_number = 0;
 	INIT_LIST_HEAD(&tcp_ses->tcp_ses_list);
 	INIT_LIST_HEAD(&tcp_ses->smb_ses_list);
@@ -2983,14 +2985,13 @@ CIFSTCon(unsigned int xid, struct cifsSesInfo *ses,
 #ifdef CONFIG_CIFS_WEAK_PW_HASH
 		if ((global_secflags & CIFSSEC_MAY_LANMAN) &&
 		    (ses->server->secType == LANMAN))
-			calc_lanman_hash(tcon->password, ses->server->cryptKey,
+			calc_lanman_hash(tcon->password, ses->cryptKey,
 					 ses->server->secMode &
 					    SECMODE_PW_ENCRYPT ? true : false,
 					 bcc_ptr);
 		else
 #endif /* CIFS_WEAK_PW_HASH */
-		SMBNTencrypt(tcon->password, ses->server->cryptKey,
-			     bcc_ptr);
+		SMBNTencrypt(tcon->password, ses->cryptKey, bcc_ptr);
 
 		bcc_ptr += CIFS_SESS_KEY_SIZE;
 		if (ses->capabilities & CAP_UNICODE) {
@@ -3175,6 +3176,15 @@ int cifs_setup_session(unsigned int xid, struct cifsSesInfo *ses,
 	if (rc) {
 		cERROR(1, "Send error in SessSetup = %d", rc);
 	} else {
+		mutex_lock(&ses->server->srv_mutex);
+		if (!server->session_estab) {
+			memcpy(&server->session_key.data,
+				&ses->auth_key.data, ses->auth_key.len);
+			server->session_key.len = ses->auth_key.len;
+			ses->server->session_estab = true;
+		}
+		mutex_unlock(&server->srv_mutex);
+
 		cFYI(1, "CIFS Session Established successfully");
 		spin_lock(&GlobalMid_Lock);
 		ses->status = CifsGood;

fs/cifs/sess.c

@@ -402,7 +402,7 @@ static int decode_ntlmssp_challenge(char *bcc_ptr, int blob_len,
 		return -EINVAL;
 	}
 
-	memcpy(ses->server->cryptKey, pblob->Challenge, CIFS_CRYPTO_KEY_SIZE);
+	memcpy(ses->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
@@ -591,17 +591,12 @@ CIFS_SessSetup(unsigned int xid, struct cifsSesInfo *ses,
 	int bytes_remaining;
 	struct key *spnego_key = NULL;
 	__le32 phase = NtLmNegotiate; /* NTLMSSP, if needed, is multistage */
-	bool first_time;
 	int blob_len;
 	char *ntlmsspblob = NULL;
 
 	if (ses == NULL)
 		return -EINVAL;
 
-	read_lock(&cifs_tcp_ses_lock);
-	first_time = is_first_ses_reconnect(ses);
-	read_unlock(&cifs_tcp_ses_lock);
-
 	type = ses->server->secType;
 
 	cFYI(1, "sess setup type %d", type);
@@ -672,7 +667,7 @@ CIFS_SessSetup(unsigned int xid, struct cifsSesInfo *ses,
 		/* BB calculate hash with password */
 		/* and copy into bcc */
 
-		calc_lanman_hash(ses->password, ses->server->cryptKey,
+		calc_lanman_hash(ses->password, ses->cryptKey,
 				 ses->server->secMode & SECMODE_PW_ENCRYPT ?
 					true : false, lnm_session_key);
 
@@ -699,15 +694,11 @@ CIFS_SessSetup(unsigned int xid, struct cifsSesInfo *ses,
 			cpu_to_le16(CIFS_SESS_KEY_SIZE);
 
 		/* calculate session key */
-		SMBNTencrypt(ses->password, ses->server->cryptKey,
-			     ntlm_session_key);
+		SMBNTencrypt(ses->password, ses->cryptKey, ntlm_session_key);
 
-		if (first_time) /* should this be moved into common code
-				  with similar ntlmv2 path? */
-			cifs_calculate_session_key(&ses->server->session_key,
-				ntlm_session_key, ses->password);
+		cifs_calculate_session_key(&ses->auth_key,
+					ntlm_session_key, ses->password);
 		/* copy session key */
-
 		memcpy(bcc_ptr, (char *)ntlm_session_key, CIFS_SESS_KEY_SIZE);
 		bcc_ptr += CIFS_SESS_KEY_SIZE;
 		memcpy(bcc_ptr, (char *)ntlm_session_key, CIFS_SESS_KEY_SIZE);
@@ -794,17 +785,14 @@ CIFS_SessSetup(unsigned int xid, struct cifsSesInfo *ses,
 		}
 		/* bail out if key is too long */
 		if (msg->sesskey_len >
-		    sizeof(ses->server->session_key.data.krb5)) {
+		    sizeof(ses->auth_key.data.krb5)) {
 			cERROR(1, "Kerberos signing key too long (%u bytes)",
 				msg->sesskey_len);
 			rc = -EOVERFLOW;
 			goto ssetup_exit;
 		}
-		if (first_time) {
-			ses->server->session_key.len = msg->sesskey_len;
-			memcpy(ses->server->session_key.data.krb5,
-				msg->data, msg->sesskey_len);
-		}
+		ses->auth_key.len = msg->sesskey_len;
+		memcpy(ses->auth_key.data.krb5, msg->data, msg->sesskey_len);
 		pSMB->req.hdr.Flags2 |= SMBFLG2_EXT_SEC;
 		capabilities |= CAP_EXTENDED_SECURITY;
 		pSMB->req.Capabilities = cpu_to_le32(capabilities);