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If "\001" is set in the string field by users, it can't be validated before sending. The field is considered as user expected. But it could be validated when received. There are three cases:
(1)Error incorrect format when Agent receives.
e.g. newOrderSingle.set(new Symbol("\001WAKEN"));
8=FIX.4.4_9=142_35=D_34=346_49=ICBC_50=operator001_52=20071128-03:03:37.140_56=XXX_212=346_11=123_38=1_40=2_44=1_54=1_55=WAKEN_60=20071128-11:03:37.125_10=XXX
Agent: [ERROR] quickfix.mina.acceptor.AcceptorIoHandler - Invalid message: bad tag format: For input string: "WAKEN_60"
e.g. newOrderSingle.set(new Symbol("WAK\001EN"));
8=FIX.4.4_9=142_35=D_34=329_49=ICBC_50=operator001_52=20071128-
03:00:50.875_56=XXX_212=329_11=123_38=1_40=2_44=1_54=1_55=WAK_EN_60=20071128-11:00:50.875_10=XXX_
Agent: [ERROR] quickfix.mina.acceptor.AcceptorIoHandler - Invalid message: bad tag format: For input string: "EN_60"
e.g. newOrderSingle.set(new Symbol("WAKEN\001"));
8=iMIX.1.0_9=142_35=D_34=365_49=ICBC_50=operator001_52=20071128-
03:06:13.671_56=XXX_212=365_11=123_38=1_40=2_44=1_54=1_55=WAKEN_60=20071128-11:06:13.671_10=XXX
Agent: [ERROR] quickfix.mina.acceptor.AcceptorIoHandler - Invalid message: bad tag format: For input string: "_60"
e.g. newOrderSingle.set(new Symbol("WAK\001=EN"));
8=iMIX.1.0_9=143_35=D_34=312_49=ICBC_50=operator001_52=20071128-
02:56:44.578_56=XXX_212=312_11=123_38=1_40=2_44=1_54=1_55=WAK_=EN_60=20071128-
10:56:44.562_10=XXX_
Agent:[ERROR] quickfix.mina.acceptor.AcceptorIoHandler - Invalid message: bad tag format: For input string: ""
(2)The message is rejected as expected.
e.g. newOrderSingle.set(new Symbol("WAK\001123=EN"));
8=iMIX.1.0_9=146_35=D_34=269_49=ICBC_50=operator001_52=20071128-
02:50:38.406_56=XXX_212=269_11=123_38=1_40=2_44=1_54=1_55=WAK_123=EN_60=20071128-
10:50:38.406_10=XXX_
Incorrect data format for value
e.g. newOrderSingle.set(new Symbol("\001123=EN"));
8=iMIX.1.0_9=143_35=D_34=248_49=ICBC_50=operator001_52=20071128-
02:49:02.406_56=XXX_212=248_11=123_38=1_40=2_44=1_54=1_55=_123=EN_60=20071128-
10:49:02.406_10=XXX_
Tag specified without a value
e.g. newOrderSingle.set(new Symbol("WAKEN\001123="));
8=iMIX.1.0_9=146_35=D_34=383_49=ICBC_50=operator001_52=20071128-
03:12:25.546_56=XXX_212=383_11=123_38=1_40=2_44=1_54=1_55=WAKEN_123=_60=20071128-
11:12:25.531_10=XXX_
Tag specified without a value
(3)The message is received successfully, but it is wrong. The result is critical. It will be used to attack the Server. This mustn't absolutely happen.
e.g. newOrderSingle.set(new Symbol("WAKEN\00110048=2"));
8=iMIX.1.0_9=149_35=D_34=449_49=ICBC_50=operator001_52=20071128-
03:21:47.031_56=XXX_212=449_11=123_38=1_40=2_44=1_54=1_55=WAKEN_10048=2_60=20071128-
11:21:47.015_10=XXX_
Solution 1
Encode the StringField at the Client, and decode at the Server. The encode and decode can be implemented in class StringField.
Fault:
In the FieldType "DATA", "\001" is permited. Its length is defined by the former field rather than by the position of "\001". So it is not affected by "\001". When encoded, its length will be changed. So the former field's value must be modified. To avoid this, a new class must be added instead of StringField. Make all
the "DATA" type extend StringField.
Solution 2
In the FIX protocol, the String field is not permit to be set as '\001'. So we can throw Exception directly or replace '\001' with ' ' in the StringField.
This can be implemented in class stringField. When construct a StringField except DATA fieldType, if find "\001", throw Exception directly or replace '\001' with ' '.
I think the solution 2 is better. The concisest method is to judge the DataField by tags. Now there are at least 3 pairs of DataField: 93/89, 95/96, 354/355.
Hard code is written:
if(field == 89||field == 96||field == 355)
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