cifs: switch servers depending on binding state

Currently a lot of the code to initialize a connection & session uses
the cifs_ses as input. But depending on if we are opening a new session
or a new channel we need to use different server pointers.

Add a "binding" flag in cifs_ses and a helper function that returns
the server ptr a session should use (only in the sess establishment
code path).

Signed-off-by: Aurelien Aptel <[e-mail]>
Signed-off-by: Steve French <[e-mail]>

fs/cifs/cifs_spnego.c

···
 struct key *
 cifs_get_spnego_key(struct cifs_ses *sesInfo)
 {
-	struct TCP_Server_Info *server = sesInfo->server;
+	struct TCP_Server_Info *server = cifs_ses_server(sesInfo);
 	struct sockaddr_in *sa = (struct sockaddr_in *) &server->dstaddr;
 	struct sockaddr_in6 *sa6 = (struct sockaddr_in6 *) &server->dstaddr;
 	char *description, *dp;

fs/cifs/cifsglob.h

···
 	bool sign;		/* is signing required? */
 	bool need_reconnect:1; /* connection reset, uid now invalid */
 	bool domainAuto:1;
+	bool binding:1; /* are we binding the session? */
 	__u16 session_flags;
 	__u8 smb3signingkey[SMB3_SIGN_KEY_SIZE];
 	__u8 smb3encryptionkey[SMB3_SIGN_KEY_SIZE];
···
 	size_t chan_max;
 	atomic_t chan_seq; /* round robin state */
 };
+
+static inline
+struct TCP_Server_Info *cifs_ses_server(struct cifs_ses *ses)
+{
+	if (ses->binding)
+		return ses->chans[ses->chan_count].server;
+	else
+		return ses->server;
+}
 
 static inline bool
 cap_unix(struct cifs_ses *ses)

fs/cifs/connect.c

···
 cifs_negotiate_protocol(const unsigned int xid, struct cifs_ses *ses)
 {
 	int rc = 0;
-	struct TCP_Server_Info *server = ses->server;
+	struct TCP_Server_Info *server = cifs_ses_server(ses);
 
 	if (!server->ops->need_neg || !server->ops->negotiate)
 		return -ENOSYS;
···
 		   struct nls_table *nls_info)
 {
 	int rc = -ENOSYS;
-	struct TCP_Server_Info *server = ses->server;
+	struct TCP_Server_Info *server = cifs_ses_server(ses);
 
 	ses->capabilities = server->capabilities;
 	if (linuxExtEnabled == 0)

fs/cifs/sess.c

···
 void build_ntlmssp_negotiate_blob(unsigned char *pbuffer,
 					 struct cifs_ses *ses)
 {
+	struct TCP_Server_Info *server = cifs_ses_server(ses);
 	NEGOTIATE_MESSAGE *sec_blob = (NEGOTIATE_MESSAGE *)pbuffer;
 	__u32 flags;
 
···
 		NTLMSSP_NEGOTIATE_128 | NTLMSSP_NEGOTIATE_UNICODE |
 		NTLMSSP_NEGOTIATE_NTLM | NTLMSSP_NEGOTIATE_EXTENDED_SEC |
 		NTLMSSP_NEGOTIATE_SEAL;
-	if (ses->server->sign)
+	if (server->sign)
 		flags |= NTLMSSP_NEGOTIATE_SIGN;
-	if (!ses->server->session_estab || ses->ntlmssp->sesskey_per_smbsess)
+	if (!server->session_estab || ses->ntlmssp->sesskey_per_smbsess)
 		flags |= NTLMSSP_NEGOTIATE_KEY_XCH;
 
 	sec_blob->NegotiateFlags = cpu_to_le32(flags);

fs/cifs/smb2ops.c

···
 {
 	int rc;
 
-	ses->server->CurrentMid = 0;
+	cifs_ses_server(ses)->CurrentMid = 0;
 	rc = SMB2_negotiate(xid, ses);
 	/* BB we probably don't need to retry with modern servers */
 	if (rc == -EAGAIN)

fs/cifs/smb2pdu.c

···
 	struct kvec rsp_iov;
 	int rc = 0;
 	int resp_buftype;
-	struct TCP_Server_Info *server = ses->server;
+	struct TCP_Server_Info *server = cifs_ses_server(ses);
 	int blob_offset, blob_length;
 	char *security_blob;
 	int flags = CIFS_NEG_OP;
···
 	memset(server->preauth_sha_hash, 0, SMB2_PREAUTH_HASH_SIZE);
 	memset(ses->preauth_sha_hash, 0, SMB2_PREAUTH_HASH_SIZE);
 
-	if (strcmp(ses->server->vals->version_string,
+	if (strcmp(server->vals->version_string,
 		   SMB3ANY_VERSION_STRING) == 0) {
 		req->Dialects[0] = cpu_to_le16(SMB30_PROT_ID);
 		req->Dialects[1] = cpu_to_le16(SMB302_PROT_ID);
···
 		total_len += 8;
 	} else {
 		/* otherwise send specific dialect */
-		req->Dialects[0] = cpu_to_le16(ses->server->vals->protocol_id);
+		req->Dialects[0] = cpu_to_le16(server->vals->protocol_id);
 		req->DialectCount = cpu_to_le16(1);
 		total_len += 2;
 	}
···
 	int rc;
 	struct cifs_ses *ses = sess_data->ses;
 	struct smb2_sess_setup_req *req;
-	struct TCP_Server_Info *server = ses->server;
+	struct TCP_Server_Info *server = cifs_ses_server(ses);
 	unsigned int total_len;
 
 	rc = smb2_plain_req_init(SMB2_SESSION_SETUP, NULL, (void **) &req,
···
 {
 	int rc = 0;
 	struct cifs_ses *ses = sess_data->ses;
+	struct TCP_Server_Info *server = cifs_ses_server(ses);
 
-	mutex_lock(&ses->server->srv_mutex);
-	if (ses->server->ops->generate_signingkey) {
-		rc = ses->server->ops->generate_signingkey(ses);
+	mutex_lock(&server->srv_mutex);
+	if (server->ops->generate_signingkey) {
+		rc = server->ops->generate_signingkey(ses);
 		if (rc) {
 			cifs_dbg(FYI,
 				"SMB3 session key generation failed\n");
-			mutex_unlock(&ses->server->srv_mutex);
+			mutex_unlock(&server->srv_mutex);
 			return rc;
 		}
 	}
-	if (!ses->server->session_estab) {
-		ses->server->sequence_number = 0x2;
-		ses->server->session_estab = true;
+	if (!server->session_estab) {
+		server->sequence_number = 0x2;
+		server->session_estab = true;
 	}
-	mutex_unlock(&ses->server->srv_mutex);
+	mutex_unlock(&server->srv_mutex);
 
 	cifs_dbg(FYI, "SMB2/3 session established successfully\n");
 	spin_lock(&GlobalMid_Lock);
···
 {
 	int type;
 
-	type = smb2_select_sectype(ses->server, ses->sectype);
+	type = smb2_select_sectype(cifs_ses_server(ses), ses->sectype);
 	cifs_dbg(FYI, "sess setup type %d\n", type);
 	if (type == Unspecified) {
 		cifs_dbg(VFS,
···
 		const struct nls_table *nls_cp)
 {
 	int rc = 0;
-	struct TCP_Server_Info *server = ses->server;
+	struct TCP_Server_Info *server = cifs_ses_server(ses);
 	struct SMB2_sess_data *sess_data;
 
 	cifs_dbg(FYI, "Session Setup\n");
···
 	/*
 	 * Initialize the session hash with the server one.
 	 */
-	memcpy(ses->preauth_sha_hash, ses->server->preauth_sha_hash,
+	memcpy(ses->preauth_sha_hash, server->preauth_sha_hash,
 	       SMB2_PREAUTH_HASH_SIZE);
 
 	while (sess_data->func)