Using a Nexus 4 and the latest Android API level 18 to communicate with a Mifare DESFire EV1 AES tag is giving me a headache. Following the NXP native protocol in order to write and read this type of tag, these steps must be followed:
Select application
Authenticate
Write or Read
To do it so, I use Android's IsoDep class which provides access to ISO 14443-4 properties and I/O operations. The very weird thing about it is that once I send the select application native command I get an unexpected response. Imagine I have the AID F4013D so I send:
-> 5AF4013D
<- 6E00
All possible responses must be one byte length (success 0x00 or error_code) and never two or more. Thus, the 0x6E before the success response is absolutely unexpected. It does not happen always, and when it does not and works fine, the select application and authentication processes work fine. However once authenticated the write command does not have a correct behavior, all write commands finishes with a 0xAF from the PICC instead of a success 0x00. It seems like the PICC expect some extra data when it should not (I send the correct length payload). If I send any other command I get a 0xCA (Command Aborted) error code.
-> 5AF4013D
<- 00 /*Success*/
-> AA01
<- AFA8394ED57A5E83106B4EE72FD2BB0CC4
-> AF148F525E1DDE0AD6AB60B4B615552475C91F2E8D89B8523E4465113DD5BD19C6
<- 0066D255C93F2F492AFE3715C88964F1BD /*Authentication success*/
-> 3D02000000030000222222 /*Write 3 bytes to file nº2*/
<- AF /*Unexpected, 0x00 was expected*/
As it is normal, if I send these type of commands with a personal reader (non Android NFC) it always works fine. It seems that something in the Android NFC API is going strange, when it should just be a raw data transporter which never interprets or modifies data.
I have also tried with ISO 7816-4 APDU structure with the same result. As a curiosity, with a Galaxy Nexus does not happen the select application strange response, but yes the write command one always.
(1) For the first part concerning the status code 6E00:
6E 00 is not a "strange byte 0x6E + success status code 0x00". Instead it is a response APDU status word 6E 00 ("Class not supported"). This indicates that there was previous communication with the card using APDU-based access (e.g. Android itself tried to read the card as Type 4 tag and did not reset the connection afterwards). Thus, the card will expect all further communication to be in ISO 7816-4 APDUs. In that case (i.e. if you receive an ISO 7816-4 status code like 6E 00), you could continue using DESFire APDU wrapped commands by simply wrapping your native commands.
EDIT: In fact, this is somewhat expected behavior on an NFC device. The idea is that an NFC device will automatically scan detected tags for NDEF messages. In the case of a DESFire card, the NFC device will detect the card as potential Type 4 tag. Thus the NFC device will send ISO 7816-4 APDUs as it would send to any other Type 4 tag. Hence, if the NFC device doesn't reset the communication with the tag before handing the detected tag to the app, the app can only communicate using ISO 7816-4 APDUs. Note, however, that I would consider it a bug that this happens only for some activations on the same device. In my opinion, the behavior on one specific device model should be consistent.
EDIT: While I would not consider this behavior a bug, it is actually caused by a known bug (#58773) in Android's NFC stack for devices with Broadcom NFC controller. On affected devices, the automatic presence check sends ISO 7816-4 APDUs at timed intervals that cause DESFire cards to switch into ISO 7816-4 APDU mode.
(2) For the second part concerning the (unexpected) response code 0xAF:
Could it be that your file's communication settings are setup for either "plain communication secured by MACing" or "fully enciphered communication"? In that case, simply sending the three data bytes would not be enough. Instead you would need to send either the plain data plus MAC or the padded, CRCed and encyrypted data. Hence the 0xAF indicating that the card expects further data.
EDIT: So to summarize the comments below. After sending further bytes (one byte at a time for each received 0xAF status code: AF FF) it turned out that exactly 8 more bytes were expected by the card. 8 bytes is exactly the size of the CMAC for AES authentication. Thus, the communication settings were set to "plain communication secured by MACing".
Related
I started my studies using NFC in Android. I can easily read and write in NDEF format.
My problem is with MIFARE DESFire EV1, I have some factory cards and I understand that they do not conform to the NFC Forum type 4 Tag specification and, consequently, do not accept to be read or written in NDEF format (when in their factory configuration).
I can get access to the tag through android.nfc.tech.NfcA or android.nfc.tech.IsoDep.
So far I understand that I need to use IsoDep.transceive() method to pass commands that enable me to build an NFC Forum Type 4 compliant tag.
But I'm having a lot of trouble. I'm using TagWriter and it does the service perfectly. Every time I use the NDEF dataset it automatically performs a routine that makes the card an NFC Forum Type 4 Tag and, consequently, an NDEF tag.
However, I could not find any simple example to do this procedure myself. Even after reading the specification document NFCForum-TS-Type-4-Tag_2.0, I'm still very lost.
Is there any practical example to do the process that the TagWriter application does?
Recognize NfcA / IsoDep (ok here)
Make the card conform to the NFC Forum Type 4 Tag specification
Start recognizing the tag as android.nfc.tech.Ndef
Enable read and write of NDEF
The procedure to prepare MIFARE DESFire EV1 as an NFC Forum Type 4 Tag (V2.0) is not part of the platform independend NFC Forum specifications. Instead, this procedure is defined by the chip manufacturer (NXP) in their application note AN11004: MIFARE DESFire as Type 4 Tag. The procedure is about the following:
If Android already detects the Ndef tag technology, you are done. Since Android tries to detect the NDEF tag application and an NDEF message contained in the NDEF data file, finding the Ndef tag technology means that the tag is already prepared for NDEF (i.e. it already is configured as NFC Forum Type 4 Tag).
Else, you would check if the tag really is a DESFire EV1 tag. You can do this based on the type identification procedure described in AN10833: MIFARE Type Identification Procedure and based on the version information obtained from the DESFire tag.
Once you know that the tag is a DESFire EV1 tag (and that you have sufficient access to the master application in order to apply the necessary modifications to the tag, which may require and authentication step), you would first create the NDEF Tag Application. This is a DESFire application that has its ISO 7816-4 DF name (= AID) set to D2760000850101 during creation. The values that you chose for the DESFire AID, the ISO file ID are not important for proper T4T operation (note that this is different for the pre-EV1 generation of DESFire). The key settings depend on your usage scenario. The only other important parameter that you need to set during application creation is to allow ISO 7816-4 file identifiers for files within the application (bit 5 in the Key Settings 2 byte set to '1').
Select the newly created application.
Create a new standard data file, the capability container file, with a size of 15 bytes. You need to set the ISO 7816-4 file ID to E103. Make sure to allow plain communication by setting the Com.Set. byte to 0x00. Set the Access Rights field so that you can later modify the file contents during the initialization.
Create another new standard data file, the NDEF data file. If you only use the tag as NDEF tag, you would typically use all the remaining available space. Set the ISO 7816-4 file ID to E104. Make sure to allow plain communication by setting the Com.Set. byte to 0x00. Set the Access Rights field to 0xE000 for a read-only tag or 0xEEE0 for a tag that should allow read and write access through the Ndef tag technology.
Select the capability container file and write the capability container data to it:
000F 20 003A 0034 04 06 E104 xxxx 00 yy
where xxxx is the size of the NDEF data file and yy is 0x00 if the file is freely writable or 0xFF if the file is read-only.
Select the NDEF message file and write the first 2 bytes as 0x0000 (in order to indicate that the file is empty).
Note that creating the NDEF Tag Application structures on a DESFire (EV1) card requires you to use either the native or the wrapped native command set of MIFARE DESFire. Since some versions of Android cause known problems with the native commands, you are better off using wrapped native commands. You can find details on the DESFire command set in the DESFire product datasheets (available only under NDA from NXP).
I have an LG D320n Android phone, elechouse's PN532 nfc module and Stollmann's NFCPlayer with which I can read NFC tags properly.
I tested a sample from here: https://github.com/grundid/host-card-emulation-sample
It works fine, when I read one Android device as tag with another Android device as reader. But I can not read the Android device as tag with PN532 reader through NFCPlayer. I want reader to read an NDEF message from the Android device acting as a tag, but NFCPlayer doesn't even recognise the Android device. I think I have to write some modifications on the Android side but I can't figure it out what to do. I think I don't have enough knowlege about how NFC communication and HCE work, even though I read this:
https://developer.android.com/guide/topics/connectivity/nfc/hce.html
I would really appreciate any guideline that could help me understand what am I missing here.
The grundid example app should be discovered by NFCPlayer as a "legacy tag" (tab "R/W: Legacy") as it does not implement the NDEF abstraction layer. On that tab, you can exchange PDUs (APDUs in the case of HCE) with the emulated smartcard. A valid APDU for the example app would be
00 A4 04 00 07 F0010203040506 00
You can send this APDU by typing it into the PDU field and clicking on the "Exch. PDU" button. Note that the grundid HCE app does not even implement ISO/IEC 7816-4 response APDUs. Hence, you may run into troubles with some contactless smartcard readers.
If you want your emulated smartcard to be discoverabe by NFCPlayer as NFC Forum Type 4 tag containing an NDEF message (tab "R/W: NDEF"), you would need to implement the NFC Forum Type 4 Tag Operation specification (as defined by the NFC Forum. This specification defines how data must be stored on an (emulated) ISO/IEC 14443-4 smartcard to be interpreted as NDEF tag. As a starting point you could use this NDEF on HCE example app (though, the quality and reliability of that code is questionable). This example implements the smartcard filesystem for storing NDEF data.
We ran into Read Binary presence check bug on Broadcom NFC stack. Samsung S4(4.2.2) is sending random read binary commands 00 B0 00 00 01.
I have no flexibility to move to Android 4.4 with reader mode API support that allows delaying presence checks.
My specific question is what response is expected by NFC stack on Android device that usage Read binary based presence check?
Will it be safe to implement a specific response to these read binary commands to gracefully execute a command response sequence?
To avoid selection of Tag application we are already returning 6A82 (Application not found)
In general, you can respond with whatever response code you want, as long as you send a properly formatted response APDU. Typically you would want to send a negative response code, e.g.
0x6986: Command not allowed (no current EF)
Of course if you use the READ BINARY command as part of your protocol, it could just as well happen, that the phone receives the first byte of the currently selected EF.
I want to route APDUs I get from an NFC Reader to the SIM Card. According to the HCE documentation I thought it would be possible simply by creating an OffHostApduService with the according routing-entries (which I did).
Sadly, the SIM does not seem to get any APDUs. SELECT-Commands that work when the SIM is directly attached to my workstation by a SIM-Reader return with 6a82 (File not found).
In LogCat I found two interesting bits of information:
Every time I shoot a select command which should be routed to the SIM, I get these entries:
01-14 10:44:18.501: D/BrcmNfcJni(1009): RoutingManager::stackCallback: event=0x17
01-14 10:44:18.501: D/BrcmNfcJni(1009): RoutingManager::stackCallback: NFA_CE_DATA_EVT; h=0x302; data len=12
01-14 10:44:18.501: D/HostEmulationManager(1009): notifyHostEmulationData
I think that this is a clue that the routing is not set correctly, since I think the Android OS should not be aware when the routing to the SIM is active, and a select or another command is sent to the SIM.
Every time I remove the phone from the NFC field of the reader, I receive the following error:
01-14 10:46:48.791: E/BrcmNfcNfa(1009): UICC[0x0] is not activated
I tried to track the cause of this error down and found the file external/libnfc-nci/src/nfa/ce/nfa_ce_act.chere which seems to belong to the Broadcom NFC Driver.
I think that the mistake is that the application cannot set the correct routing for the APDUs since the driver thinks that the SIM is not activated. In the moment I send the commands, the SIM is unlocked (PIN-Entry), but I doubt that this has anything to do with it since I don't have to unlock the SIM before using it in the card reader.
I use a Nexus 5 for testing. Does anybody have experience and / or a working example where the APDUs can be routed to the SIM instead of the CPU?
A quick check (analyzing the signals on the SWP pin of a UICC inserted into the device) revealed that the Nexus 5 is not activating the SIM as an NFC secure element (neither at boot nor when putting the phone on a smartcard reader).
However, I found two interesting files on the device's system partition:
/system/etc/libnfc-brcm-20791b05.conf and
/system/etc/libnfc-brcm.conf.
These two files seem to provide the configuration for the NFC controller (the first one a chip-sepecific configuration and the second one a chip-family specific one?).
After unlocking the bootloader, I was able to modify those files through adb by booting a clockworkmod recovery image, so I did some experimenting with the configuration parameters.
The result is that I managed to let the device activate the UICC (UICC was activated and registered its CE gates through SWP?), the device sometimes even notified the UICC about field status changes. However, with none of my modified configurations, I was able to get the reader to smoothly discover card emulation (this was working before, when only HCE was available on the device) nor to communicate with the UICC.
The interesting parameters in /system/etc/libnfc-brcm.conf seem to be:
NFA_MAX_EE_SUPPORTED: This is currently set to 0. I tried a value of 3, which seems to be the default.
ACTIVE_SE: This is currently set to 0 (no active SE). I tried to uncomment that line to let the device use the first SE detected.
NFA_HCI_STATIC_PIPE_ID_??: Should not be necessary but on out GS4 this is set to 0x71 for ?? = F3 and F4.
UICC_LISTEN_TECH_MASK: This is set to 0x00 on our GS4.
REGISTER_VIRTUAL_SE: I left this as it was (== commented out).
SCREEN_OFF_POWER_STATE: I did not experiment with this, but on our GS4 this is set to 3 (screen-off CE).
The interesting parameters in /system/etc/libnfc-brcm-20791b05.conf seem to be:
NFA_DM_START_UP_CFG: I've tried the commented-out parameters for UICC and I tried to use the configuration from our GS4. The value starts with a length byte and is structured in TLV format (one tag byte, one length byte, parameter data). The relevant tag for UICC activation seems to be C2, where the upper two bits in the second parameter byte disable the SWP interfaces of the NFC controller if set.
NFA_DM_PRE_DISCOVERY_CFG: The comments suggest that this need to be uncommented for UICC support.
It's been a while since I last played with card emulation on Android but AFAIK (I could be wrong), secure element access (internal or inside SIM) has not yet been opened to all developers (without some hacking). There are many non-technical issues regarding SE control which seem not yet solved (who keeps the biggest slice of the cake the Telcos or service providers?).
The news is that Google has taken a different approach with KitKat and its HCE, which basically consists on implementing a NFC card emulation mode without hardware secure element. IMHO this basically breaks the security required for the interesting card emulation mode applications: e-payment, ticketing, authentication, etc. Nexus 5 lacks such secure element and I doubt Google will pander to carriers by easing the access to secure element inside SIM, so I guess it still will not be possible to send APDUs to the SIM with stock firmware.
If you add the following to /etc/libnfc-brcm.conf
DEFAULT_ISODEP_ROUTE=0xF3
the UICC will receive APDUs
You also need all modifications above in libnfc-brcm.conf and libnfc-brcm-20791b05.conf
Up to Jelly Bean 4.3, normal way is to use nfc_extras and its method CardEmulationRoute (<route>, <nfcEe>) to route the UICC to the RF.
But on KITKAT, this brutal modification through DEFAULT_ISODEP_ROUTE is enough to have UICC Card Emulation enabled.
I am working on an application for Android reading a contactless smart card but I have some problems with my Galaxy S3.
Before to describe problems, I need to precise that on a PC, I can communicate perfectly with the card using the smartcardio API in Java and NFC readers from different manufacturers.
This card is detected as supporting technologies "IsoDep" and "NfcB" by the NFC stack.
However, when I send my apdu command with "transceive", I get an exception "Transceive failed". I have tried to increase timeout but no better result.
iso = IsoDep.get(tag);
if (iso!=null) {
try {
iso.connect();
// txMessage is a TextView object used for debugging purpose
txMessage.setText("Max:"+iso.getMaxTransceiveLength()+" timeout:"+iso.getTimeout()+" connected:"+iso.isConnected());
iso.setTimeout(2000);
txMessage.setText("Max:"+iso.getMaxTransceiveLength()+" timeout:"+iso.getTimeout()+" connected:"+iso.isConnected());
byte[] command = new byte[] {(byte) 0x00, (byte) 0xA4, (byte) 0x04,(byte) 0x00, (byte) 0x06,(byte) 0xA0,(byte) 0x00,(byte) 0x00, (byte) 0x00,(byte) 0x12,(byte) 0x00};
byte[] response = iso.transceive(command);
} catch (IOException e) {
txMessage.setText(txMessage.getText()+"\n"+e.getMessage());
}
}
When running this code, I get:
Max:261 timeout:309 connected: true
Max:261 timeout:2474 connected: true
Transceive failed
I have noticed that this card requires to be very close of the NFC antenna to work. I need to remove the additional plastic protection case (not the back cover) of my phone in order the card would be detected (I guess powered).
Before to post, I have read NFC typeb card not getting detected by any NFC application (like:nfctaginfo) and Android isodep.isConnected() returns false and maximum Transceive length:0 byte ,for type B card.? and several other posts elsewhere (http://forum.xda-developers.com/showthread.php?t=1705970 , http://code.google.com/p/android/issues/detail?id=35960 ) but I did not find a solution.
A possible solution would be to try to communicate with an external antenna but I am not sure where to connect it? On battery connector where there is no "+" and "-"?
Another solution would be to try to communicate with the card with NfcB (NfcB nfcb = NfcB.get(tag);), but I do not know the ISO14443-3B protocol (I only know quite well APDU, T0-TPDU but not other TPDU protocols).
Just to be sure, I have updated my phone to Android 4.1.2 (instead of 4.1.1) but no better result.
I have a Samsung Galaxy S3 too and I noticed that the connection performance for TypeB contactless cards is worse than for TypeA. Raising the timeout value seems to be a quick fix for problems of this kind, but as it didn't work for you, the problem might be with the strength of the RF-field. Have you tested if the call of transceive() fails because of the timeout or because of a connection loss? Maybe you could try raising the timeout even further, some operations might take a long time on a smart card.
Another suggestion to your problem is to remove the backcover of your S3 and place the smart card directly on the battery (the NFC antenna is integrated in there). In my experience it makes a slight difference where the chip is located on the smart card, so you could experiment with the orientation of the card. You might test this by sliding the card onto the battery from the bottom of the device to the top.
In my work with the Galaxy S3 (Android 4.1.1) I was able to connect to and transceive data to TypeA and TypeB contactless smart cards (German eID cards). I noticed that the TypeB card was lost sometimes without any reason while being idle. But I can send and receive data with it anyway. Even when the Chip on the card has to perform some computation and hence needs slightly more power from the RF field, the field of the NFC antenna seems sufficiently strong to keep the connection in my case. Maybe your card is not properly designed to work with lower power RF fields? Unfortunately to my knowledge there is no possibility to raise the power output of the NFC antenna on Android devices.
Communicating via the NfcB (NfcB nfcb = NfcB.get(tag);) does not seem to make any difference to me. I am able to comunicate via the IsoDep Object and transceive data perfectly.
Using an external or additional antenna would be worth a try. In this YouTube video it is shown how one can put an additional NFC antenna into the Galaxy S4. In the video you will notice the external antenna pins on the back of the S4. When watching the third picture here (Galaxy SIII teardown) - the one with the battery taken out - you will notice that there are additional antenna pins on the back of the SIII as well. The two golden contact pins on the left side. Googling a bit showed that these pins are named 'ANT500' and 'ANT501', so they are probably external NFC antenna contacts. If you search for "Samsung Galaxy Note2 external NFC antenna" or something similar on eBay (or any search engine), you will get the antenna used in the YouTube video. There are no official external NFC antennas for the SIII nor for the S4, but probably it will work. The antenna is not very expensive (currently around $5), so you might give it a try.
It is definitely a timeout thing, and a compatibility thing with NXP NFC chips (like the one in the S3)
I have worked with Type B tags on an antenna with a higher Q factor than that of a typical mobile phone antenna, and when doing ISO-DEP I need to still change the default timeouts of the NFC chip that I'm using (NXP PN532). Type A modulation was developed by Phillps, now NXP. Type B modulation was developed by Motorolla, and is under license to NXP for its reader chips, so only a basic implementation is included relative the the Type A implementation.
I am not doing this on an Android, but an embedded platform, so I have full access to the NFC chip's features. Thus, only by using a more basic transeiving method that requires the application to handle the 14443-4 protocol and extending the timeout tolerance of the reader was I able to talk to a Type B tag using ISO-DEP
Android 4.4 has something called reader mode, that may have a feature that enables you to extend this timeout.