cifs: fix small mempool leak in SMB2_negotiate()

In some cases of failure (dialect mismatches) in SMB2_negotiate(), after
the request is sent, the checks would return -EIO when they should be
rather setting rc = -EIO and jumping to neg_exit to free the response
buffer from mempool.
Signed-off-by: Enzo Matsumiya <ematsumiya@suse.de>
Cc: stable@vger.kernel.org
Reviewed-by: Ronnie Sahlberg <lsahlber@redhat.com>
Signed-off-by: Steve French <stfrench@microsoft.com>

fs/cifs/smb2pdu.c

@@ -965,16 +965,17 @@ SMB2_negotiate(const unsigned int xid,
 	} else if (rc != 0)
 		goto neg_exit;
 
+	rc = -EIO;
 	if (strcmp(server->vals->version_string,
 		   SMB3ANY_VERSION_STRING) == 0) {
 		if (rsp->DialectRevision == cpu_to_le16(SMB20_PROT_ID)) {
 			cifs_server_dbg(VFS,
 				"SMB2 dialect returned but not requested\n");
-			return -EIO;
+			goto neg_exit;
 		} else if (rsp->DialectRevision == cpu_to_le16(SMB21_PROT_ID)) {
 			cifs_server_dbg(VFS,
 				"SMB2.1 dialect returned but not requested\n");
-			return -EIO;
+			goto neg_exit;
 		} else if (rsp->DialectRevision == cpu_to_le16(SMB311_PROT_ID)) {
 			/* ops set to 3.0 by default for default so update */
 			server->ops = &smb311_operations;
@@ -985,7 +986,7 @@ SMB2_negotiate(const unsigned int xid,
 		if (rsp->DialectRevision == cpu_to_le16(SMB20_PROT_ID)) {
 			cifs_server_dbg(VFS,
 				"SMB2 dialect returned but not requested\n");
-			return -EIO;
+			goto neg_exit;
 		} else if (rsp->DialectRevision == cpu_to_le16(SMB21_PROT_ID)) {
 			/* ops set to 3.0 by default for default so update */
 			server->ops = &smb21_operations;
@@ -999,7 +1000,7 @@ SMB2_negotiate(const unsigned int xid,
 		/* if requested single dialect ensure returned dialect matched */
 		cifs_server_dbg(VFS, "Invalid 0x%x dialect returned: not requested\n",
 				le16_to_cpu(rsp->DialectRevision));
-		return -EIO;
+		goto neg_exit;
 	}
 
 	cifs_dbg(FYI, "mode 0x%x\n", rsp->SecurityMode);
@@ -1017,9 +1018,10 @@ SMB2_negotiate(const unsigned int xid,
 	else {
 		cifs_server_dbg(VFS, "Invalid dialect returned by server 0x%x\n",
 				le16_to_cpu(rsp->DialectRevision));
-		rc = -EIO;
 		goto neg_exit;
 	}
+
+	rc = 0;
 	server->dialect = le16_to_cpu(rsp->DialectRevision);
 
 	/*