Martin Paljak wrote: > Hello, > On Sep 7, 2010, at 12:45 PM, Viktor TARASOV wrote: > >> in r4668 the APDU validity condition >> 'apdu->le > 256' was replaced by 'apdu->le > card->max_recv_size'. >> >> It's comprehensible but revealed the ambiguity of the 'max_recv_size'. >> The unique card's max_recv_size cannot be used to validate all the APDUs >> of card. >> >> For example, not all the cards accept Le = 256 for the 'READ BINARY' >> command, >> but the same card returns 256 bytes of the signature with RSA key 2048bit. >> > > Do you mean Le encoding of 0x00 == 256 and "If Le=0x00, within the limit of > 256 for a short Le field , all the available bytes should be returned." >
In the 'init' of some card drivers there is something like "card->max_recv_size = 255", for example MyEID . This card has to return 256 bytes of signature computed with 2048 bit key, but cannot, because APDU do not pass the "apdu->le > card->max_recv_size" control. >> My question is, >> should the test 'apdu->le > card->max_recv_size' be removed from the >> APDU validity control, >> or in each card driver, that can be sensible to this problem, the (for >> ex.) 'compute_signature' command have >> to enveloped by change/restore of 'max_recv_size'. >> > > > Cards that misbehave are usually exceptions. At the same time, a long time > ago I used to have a serial reader that could only do 24X something in one > go. > > If a card driver limits the maximum receive size, the encoding of 0x00 would > mean that the card driver author knows that Le coding of "all available > bytes" (0x00) from the card will not be between 0..256 bytes but between > 0..max_recv_size bytes. > -- Viktor Tarasov <viktor.tara...@opentrust.com> _______________________________________________ opensc-devel mailing list opensc-devel@lists.opensc-project.org http://www.opensc-project.org/mailman/listinfo/opensc-devel
