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Diffstat (limited to 'qemu/docs/libcacard.txt')
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diff --git a/qemu/docs/libcacard.txt b/qemu/docs/libcacard.txt deleted file mode 100644 index 8db421d3a..000000000 --- a/qemu/docs/libcacard.txt +++ /dev/null @@ -1,483 +0,0 @@ -This file documents the CAC (Common Access Card) library in the libcacard -subdirectory. - -Virtual Smart Card Emulator - -This emulator is designed to provide emulation of actual smart cards to a -virtual card reader running in a guest virtual machine. The emulated smart -cards can be representations of real smart cards, where the necessary functions -such as signing, card removal/insertion, etc. are mapped to real, physical -cards which are shared with the client machine the emulator is running on, or -the cards could be pure software constructs. - -The emulator is structured to allow multiple replaceable or additional pieces, -so it can be easily modified for future requirements. The primary envisioned -modifications are: - -1) The socket connection to the virtual card reader (presumably a CCID reader, -but other ISO-7816 compatible readers could be used). The code that handles -this is in vscclient.c. - -2) The virtual card low level emulation. This is currently supplied by using -NSS. This emulation could be replaced by implementations based on other -security libraries, including but not limitted to openssl+pkcs#11 library, -raw pkcs#11, Microsoft CAPI, direct opensc calls, etc. The code that handles -this is in vcard_emul_nss.c. - -3) Emulation for new types of cards. The current implementation emulates the -original DoD CAC standard with separate pki containers. This emulator lives in -cac.c. More than one card type emulator could be included. Other cards could -be emulated as well, including PIV, newer versions of CAC, PKCS #15, etc. - --------------------- -Replacing the Socket Based Virtual Reader Interface. - -The current implementation contains a replaceable module vscclient.c. The -current vscclient.c implements a sockets interface to the virtual ccid reader -on the guest. CCID commands that are pertinent to emulation are passed -across the socket, and their responses are passed back along that same socket. -The protocol that vscclient uses is defined in vscard_common.h and connects -to a qemu ccid usb device. Since this socket runs as a client, vscclient.c -implements a program with a main entry. It also handles argument parsing for -the emulator. - -An application that wants to use the virtual reader can replace vscclient.c -with its own implementation that connects to its own CCID reader. The calls -that the CCID reader can call are: - - VReaderList * vreader_get_reader_list(); - - This function returns a list of virtual readers. These readers may map to - physical devices, or simulated devices depending on vcard the back end. Each - reader in the list should represent a reader to the virtual machine. Virtual - USB address mapping is left to the CCID reader front end. This call can be - made any time to get an updated list. The returned list is a copy of the - internal list that can be referenced by the caller without locking. This copy - must be freed by the caller with vreader_list_delete when it is no longer - needed. - - VReaderListEntry *vreader_list_get_first(VReaderList *); - - This function gets the first entry on the reader list. Along with - vreader_list_get_next(), vreader_list_get_first() can be used to walk the - reader list returned from vreader_get_reader_list(). VReaderListEntries are - part of the list themselves and do not need to be freed separately from the - list. If there are no entries on the list, it will return NULL. - - VReaderListEntry *vreader_list_get_next(VReaderListEntry *); - - This function gets the next entry in the list. If there are no more entries - it will return NULL. - - VReader * vreader_list_get_reader(VReaderListEntry *) - - This function returns the reader stored in the reader List entry. Caller gets - a new reference to a reader. The caller must free its reference when it is - finished with vreader_free(). - - void vreader_free(VReader *reader); - - This function frees a reference to a reader. Readers are reference counted - and are automatically deleted when the last reference is freed. - - void vreader_list_delete(VReaderList *list); - - This function frees the list, all the elements on the list, and all the - reader references held by the list. - - VReaderStatus vreader_power_on(VReader *reader, char *atr, int *len); - - This function simulates a card power on. A virtual card does not care about - the actual voltage and other physical parameters, but it does care that the - card is actually on or off. Cycling the card causes the card to reset. If - the caller provides enough space, vreader_power_on will return the ATR of - the virtual card. The amount of space provided in atr should be indicated - in *len. The function modifies *len to be the actual length of of the - returned ATR. - - VReaderStatus vreader_power_off(VReader *reader); - - This function simulates a power off of a virtual card. - - VReaderStatus vreader_xfer_bytes(VReader *reader, unsigne char *send_buf, - int send_buf_len, - unsigned char *receive_buf, - int receive_buf_len); - - This function sends a raw apdu to a card and returns the card's response. - The CCID front end should return the response back. Most of the emulation - is driven from these APDUs. - - VReaderStatus vreader_card_is_present(VReader *reader); - - This function returns whether or not the reader has a card inserted. The - vreader_power_on, vreader_power_off, and vreader_xfer_bytes will return - VREADER_NO_CARD. - - const char *vreader_get_name(VReader *reader); - - This function returns the name of the reader. The name comes from the card - emulator level and is usually related to the name of the physical reader. - - VReaderID vreader_get_id(VReader *reader); - - This function returns the id of a reader. All readers start out with an id - of -1. The application can set the id with vreader_set_id. - - VReaderStatus vreader_get_id(VReader *reader, VReaderID id); - - This function sets the reader id. The application is responsible for making - sure that the id is unique for all readers it is actively using. - - VReader *vreader_find_reader_by_id(VReaderID id); - - This function returns the reader which matches the id. If two readers match, - only one is returned. The function returns NULL if the id is -1. - - Event *vevent_wait_next_vevent(); - - This function blocks waiting for reader and card insertion events. There - will be one event for each card insertion, each card removal, each reader - insertion and each reader removal. At start up, events are created for all - the initial readers found, as well as all the cards that are inserted. - - Event *vevent_get_next_vevent(); - - This function returns a pending event if it exists, otherwise it returns - NULL. It does not block. - ----------------- -Card Type Emulator: Adding a New Virtual Card Type - -The ISO 7816 card spec describes 2 types of cards: - 1) File system cards, where the smartcard is managed by reading and writing -data to files in a file system. There is currently only boiler plate -implemented for file system cards. - 2) VM cards, where the card has loadable applets which perform the card -functions. The current implementation supports VM cards. - -In the case of VM cards, the difference between various types of cards is -really what applets have been installed in that card. This structure is -mirrored in card type emulators. The 7816 emulator already handles the basic -ISO 7186 commands. Card type emulators simply need to add the virtual applets -which emulate the real card applets. Card type emulators have exactly one -public entry point: - - VCARDStatus xxx_card_init(VCard *card, const char *flags, - const unsigned char *cert[], - int cert_len[], - VCardKey *key[], - int cert_count); - - The parameters for this are: - card - the virtual card structure which will represent this card. - flags - option flags that may be specific to this card type. - cert - array of binary certificates. - cert_len - array of lengths of each of the certificates specified in cert. - key - array of opaque key structures representing the private keys on - the card. - cert_count - number of entries in cert, cert_len, and key arrays. - - Any cert, cert_len, or key with the same index are matching sets. That is - cert[0] is cert_len[0] long and has the corresponding private key of key[0]. - -The card type emulator is expected to own the VCardKeys, but it should copy -any raw cert data it wants to save. It can create new applets and add them to -the card using the following functions: - - VCardApplet *vcard_new_applet(VCardProcessAPDU apdu_func, - VCardResetApplet reset_func, - const unsigned char *aid, - int aid_len); - - This function creates a new applet. Applet structures store the following - information: - 1) the AID of the applet (set by aid and aid_len). - 2) a function to handle APDUs for this applet. (set by apdu_func, more on - this below). - 3) a function to reset the applet state when the applet is selected. - (set by reset_func, more on this below). - 3) applet private data, a data pointer used by the card type emulator to - store any data or state it needs to complete requests. (set by a - separate call). - 4) applet private data free, a function used to free the applet private - data when the applet itself is destroyed. - The created applet can be added to the card with vcard_add_applet below. - - void vcard_set_applet_private(VCardApplet *applet, - VCardAppletPrivate *private, - VCardAppletPrivateFree private_free); - This function sets the private data and the corresponding free function. - VCardAppletPrivate is an opaque data structure to the rest of the emulator. - The card type emulator can define it any way it wants by defining - struct VCardAppletPrivateStruct {};. If there is already a private data - structure on the applet, the old one is freed before the new one is set up. - passing two NULL clear any existing private data. - - VCardStatus vcard_add_applet(VCard *card, VCardApplet *applet); - - Add an applet onto the list of applets attached to the card. Once an applet - has been added, it can be selected by its AID, and then commands will be - routed to it VCardProcessAPDU function. This function adopts the applet that - is passed into it. Note: 2 applets with the same AID should not be added to - the same card. It is permissible to add more than one applet. Multiple applets - may have the same VCardPRocessAPDU entry point. - -The certs and keys should be attached to private data associated with one or -more appropriate applets for that card. Control will come to the card type -emulators once one of its applets are selected through the VCardProcessAPDU -function it specified when it created the applet. - -The signature of VCardResetApplet is: - VCardStatus (*VCardResetApplet) (VCard *card, int channel); - This function will reset the any internal applet state that needs to be - cleared after a select applet call. It should return VCARD_DONE; - -The signature of VCardProcessAPDU is: - VCardStatus (*VCardProcessAPDU)(VCard *card, VCardAPDU *apdu, - VCardResponse **response); - This function examines the APDU and determines whether it should process - the apdu directly, reject the apdu as invalid, or pass the apdu on to - the basic 7816 emulator for processing. - If the 7816 emulator should process the apdu, then the VCardProcessAPDU - should return VCARD_NEXT. - If there is an error, then VCardProcessAPDU should return an error - response using vcard_make_response and the appropriate 7816 error code - (see card_7816t.h) or vcard_make_response with a card type specific error - code. It should then return VCARD_DONE. - If the apdu can be processed correctly, VCardProcessAPDU should do so, - set the response value appropriately for that APDU, and return VCARD_DONE. - VCardProcessAPDU should always set the response if it returns VCARD_DONE. - It should always either return VCARD_DONE or VCARD_NEXT. - -Parsing the APDU -- - -Prior to processing calling the card type emulator's VCardProcessAPDU function, the emulator has already decoded the APDU header and set several fields: - - apdu->a_data - The raw apdu data bytes. - apdu->a_len - The len of the raw apdu data. - apdu->a_body - The start of any post header parameter data. - apdu->a_Lc - The parameter length value. - apdu->a_Le - The expected length of any returned data. - apdu->a_cla - The raw apdu class. - apdu->a_channel - The channel (decoded from the class). - apdu->a_secure_messaging_type - The decoded secure messaging type - (from class). - apdu->a_type - The decode class type. - apdu->a_gen_type - the generic class type (7816, PROPRIETARY, RFU, PTS). - apdu->a_ins - The instruction byte. - apdu->a_p1 - Parameter 1. - apdu->a_p2 - Parameter 2. - -Creating a Response -- - -The expected result of any APDU call is a response. The card type emulator must -set *response with an appropriate VCardResponse value if it returns VCARD_DONE. -Responses could be as simple as returning a 2 byte status word response, to as -complex as returning a block of data along with a 2 byte response. Which is -returned will depend on the semantics of the APDU. The following functions will -create card responses. - - VCardResponse *vcard_make_response(VCard7816Status status); - - This is the most basic function to get a response. This function will - return a response the consists solely one 2 byte status code. If that status - code is defined in card_7816t.h, then this function is guaranteed to - return a response with that status. If a cart type specific status code - is passed and vcard_make_response fails to allocate the appropriate memory - for that response, then vcard_make_response will return a VCardResponse - of VCARD7816_STATUS_EXC_ERROR_MEMORY. In any case, this function is - guaranteed to return a valid VCardResponse. - - VCardResponse *vcard_response_new(unsigned char *buf, int len, - VCard7816Status status); - - This function is similar to vcard_make_response except it includes some - returned data with the response. It could also fail to allocate enough - memory, in which case it will return NULL. - - VCardResponse *vcard_response_new_status_bytes(unsigned char sw1, - unsigned char sw2); - - Sometimes in 7816 the response bytes are treated as two separate bytes with - split meanings. This function allows you to create a response based on - two separate bytes. This function could fail, in which case it will return - NULL. - - VCardResponse *vcard_response_new_bytes(unsigned char *buf, int len, - unsigned char sw1, - unsigned char sw2); - - This function is the same as vcard_response_new except you may specify - the status as two separate bytes like vcard_response_new_status_bytes. - - -Implementing functionality --- - -The following helper functions access information about the current card -and applet. - - VCARDAppletPrivate *vcard_get_current_applet_private(VCard *card, - int channel); - - This function returns any private data set by the card type emulator on - the currently selected applet. The card type emulator keeps track of the - current applet state in this data structure. Any certs and keys associated - with a particular applet is also stored here. - - int vcard_emul_get_login_count(VCard *card); - - This function returns the the number of remaining login attempts for this - card. If the card emulator does not know, or the card does not have a - way of giving this information, this function returns -1. - - - VCard7816Status vcard_emul_login(VCard *card, unsigned char *pin, - int pin_len); - - This function logs into the card and returns the standard 7816 status - word depending on the success or failure of the call. - - void vcard_emul_delete_key(VCardKey *key); - - This function frees the VCardKey passed in to xxxx_card_init. The card - type emulator is responsible for freeing this key when it no longer needs - it. - - VCard7816Status vcard_emul_rsa_op(VCard *card, VCardKey *key, - unsigned char *buffer, - int buffer_size); - - This function does a raw rsa op on the buffer with the given key. - -The sample card type emulator is found in cac.c. It implements the cac specific -applets. Only those applets needed by the coolkey pkcs#11 driver on the guest -have been implemented. To support the full range CAC middleware, a complete CAC -card according to the CAC specs should be implemented here. - ------------------------------- -Virtual Card Emulator - -This code accesses both real smart cards and simulated smart cards through -services provided on the client. The current implementation uses NSS, which -already knows how to talk to various PKCS #11 modules on the client, and is -portable to most operating systems. A particular emulator can have only one -virtual card implementation at a time. - -The virtual card emulator consists of a series of virtual card services. In -addition to the services describe above (services starting with -vcard_emul_xxxx), the virtual card emulator also provides the following -functions: - - VCardEmulError vcard_emul_init(cont VCardEmulOptions *options); - - The options structure is built by another function in the virtual card - interface where a string of virtual card emulator specific strings are - mapped to the options. The actual structure is defined by the virtual card - emulator and is used to determine the configuration of soft cards, or to - determine which physical cards to present to the guest. - - The vcard_emul_init function will build up sets of readers, create any - threads that are needed to watch for changes in the reader state. If readers - have cards present in them, they are also initialized. - - Readers are created with the function. - - VReader *vreader_new(VReaderEmul *reader_emul, - VReaderEmulFree reader_emul_free); - - The freeFunc is used to free the VReaderEmul * when the reader is - destroyed. The VReaderEmul structure is an opaque structure to the - rest of the code, but defined by the virtual card emulator, which can - use it to store any reader specific state. - - Once the reader has been created, it can be added to the front end with the - call: - - VReaderStatus vreader_add_reader(VReader *reader); - - This function will automatically generate the appropriate new reader - events and add the reader to the list. - - To create a new card, the virtual card emulator will call a similar - function. - - VCard *vcard_new(VCardEmul *card_emul, - VCardEmulFree card_emul_free); - - Like vreader_new, this function takes a virtual card emulator specific - structure which it uses to keep track of the card state. - - Once the card is created, it is attached to a card type emulator with the - following function: - - VCardStatus vcard_init(VCard *vcard, VCardEmulType type, - const char *flags, - unsigned char *const *certs, - int *cert_len, - VCardKey *key[], - int cert_count); - - The vcard is the value returned from vcard_new. The type is the - card type emulator that this card should presented to the guest as. - The flags are card type emulator specific options. The certs, - cert_len, and keys are all arrays of length cert_count. These are the - the same of the parameters xxxx_card_init() accepts. - - Finally the card is associated with its reader by the call: - - VReaderStatus vreader_insert_card(VReader *vreader, VCard *vcard); - - This function, like vreader_add_reader, will take care of any event - notification for the card insert. - - - VCardEmulError vcard_emul_force_card_remove(VReader *vreader); - - Force a card that is present to appear to be removed to the guest, even if - that card is a physical card and is present. - - - VCardEmulError vcard_emul_force_card_insert(VReader *reader); - - Force a card that has been removed by vcard_emul_force_card_remove to be - reinserted from the point of view of the guest. This will only work if the - card is physically present (which is always true fro a soft card). - - void vcard_emul_get_atr(Vcard *card, unsigned char *atr, int *atr_len); - - Return the virtual ATR for the card. By convention this should be the value - VCARD_ATR_PREFIX(size) followed by several ascii bytes related to this - particular emulator. For instance the NSS emulator returns - {VCARD_ATR_PREFIX(3), 'N', 'S', 'S' }. Do ot return more data then *atr_len; - - void vcard_emul_reset(VCard *card, VCardPower power) - - Set the state of 'card' to the current power level and reset its internal - state (logout, etc). - -------------------------------------------------------- -List of files and their function: -README - This file -card_7816.c - emulate basic 7816 functionality. Parse APDUs. -card_7816.h - apdu and response services definitions. -card_7816t.h - 7816 specific structures, types and definitions. -event.c - event handling code. -event.h - event handling services definitions. -eventt.h - event handling structures and types -vcard.c - handle common virtual card services like creation, destruction, and - applet management. -vcard.h - common virtual card services function definitions. -vcardt.h - comon virtual card types -vreader.c - common virtual reader services. -vreader.h - common virtual reader services definitions. -vreadert.h - comon virtual reader types. -vcard_emul_type.c - manage the card type emulators. -vcard_emul_type.h - definitions for card type emulators. -cac.c - card type emulator for CAC cards -vcard_emul.h - virtual card emulator service definitions. -vcard_emul_nss.c - virtual card emulator implementation for nss. -vscclient.c - socket connection to guest qemu usb driver. -vscard_common.h - common header with the guest qemu usb driver. -mutex.h - header file for machine independent mutexes. -link_test.c - static test to make sure all the symbols are properly defined. |