Hi! The attached diff introduces a workaround for the bug in the ACR122U reader that makes it use "one less" sequence number in the response frame if the request frame was longer than 64 bytes.
It works for me (and does not break on another "correct" CCID reader that I have at hand). Whether you want to merge it, or rework it, or drop it altogether if of course entirely up to you. I just wanted to share it in case it could be useful for somebody. It is possible that the bug is specific to a subset of the ACR122U readers, and there exist readers with the USB ID 072f:2200 that do not have this bug. My patch _should not_ break on them, but of course I had no way to test it. Thanks, Eugene
Index: Drivers/ccid/src/ccid_usb.c
===================================================================
--- Drivers/ccid/src/ccid_usb.c (revision 6746)
+++ Drivers/ccid/src/ccid_usb.c (working copy)
@@ -109,6 +109,12 @@
/* pointer to the multislot extension (if any) */
struct usbDevice_MultiSlot_Extension *multislot_extension;
+ int last_write_size;
+ /* bit mask for workarounds */
+ int workarounds;
+ /* workaround bitmask definition(s) */
+#define LONG_PDU_BREAKS_SEQUENCE 1
+
} _usbDevice;
/* The _usbDevice structure must be defined before including ccid_usb.h */
@@ -124,6 +130,7 @@
static int get_end_points(struct libusb_config_descriptor *desc,
_usbDevice *usbdevice, int num);
int ccid_check_firmware(struct libusb_device_descriptor *desc);
+int ccid_workarounds(struct libusb_device_descriptor *desc);
static unsigned int *get_data_rates(unsigned int reader_index,
struct libusb_config_descriptor *desc, int num);
@@ -585,6 +592,9 @@
goto end2;
}
+ usbDevice[reader_index].workarounds |=
+ ccid_workarounds(&desc);
+
#ifdef USE_COMPOSITE_AS_MULTISLOT
/* use the next interface for the next "slot" */
static_interface++;
@@ -737,6 +747,8 @@
return STATUS_UNSUCCESSFUL;
}
+ usbDevice[reader_index].last_write_size = length;
+
return STATUS_SUCCESS;
} /* WriteUSB */
@@ -784,6 +796,13 @@
if ((*length >= BSEQ_OFFSET)
&& (buffer[BSEQ_OFFSET] < *ccid_descriptor->pbSeq -1))
{
+ /* Workaround for ACR122U reader */
+ if ((usbDevice[reader_index].workarounds &
+ LONG_PDU_BREAKS_SEQUENCE) &&
+ (usbDevice[reader_index].last_write_size > 64) &&
+ (buffer[BSEQ_OFFSET] == *ccid_descriptor->pbSeq -2))
+ return STATUS_SUCCESS;
+
duplicate_frame++;
if (duplicate_frame > 10)
{
@@ -1047,6 +1066,23 @@
/*****************************************************************************
*
+ * ccid_workarounds
+ *
+ ****************************************************************************/
+int ccid_workarounds(struct libusb_device_descriptor *desc)
+{
+ /* Advanced Card Systems, Ltd ACR122U. If you send a CCID */
+ /* frame longer than 64 bytes (APDU longer than 54 bytes), */
+ /* the response frame has sequence byte one less than */
+ /* the request frame. */
+ if (desc->idVendor == 0x072f && desc->idProduct == 0x2200)
+ return LONG_PDU_BREAKS_SEQUENCE;
+ return 0;
+} /* ccid_workarounds */
+
+
+/*****************************************************************************
+ *
* get_data_rates
*
****************************************************************************/
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