Change in osmo-ccid-firmware[master]: Fix returned data in case of command TPDU

[laforge]

laforge has submitted this change. ( https://gerrit.osmocom.org/c/osmo-ccid-firmware/+/19460 )

Change subject: Fix returned data in case of command TPDU
......................................................................

Fix returned data in case of command TPDU

When Lc>0 (command TPDU), our response always copied the command
data in front of the response (which is a SW of 2 bytes in this case).

This of course confuses the hell out of users.  The response to a Lc>0
TPDU should be just the two-bytes status word.

Introduce the use of msgb->l4h for the point in the buffer from where
we receive data from the card.  all bytes before l4h are transmitted
to the card.

Change-Id: Ie3fc7437d39dc330b9f2b7d7960ad2560b6be4b7
---
M ccid_common/ccid_slot_fsm.c
M ccid_common/iso7816_fsm.c
2 files changed, 5 insertions(+), 1 deletion(-)

Approvals:
  Jenkins Builder: Verified
  laforge: Looks good to me, approved



diff --git a/ccid_common/ccid_slot_fsm.c b/ccid_common/ccid_slot_fsm.c
index 747fef3..4bd1b0d 100644
--- a/ccid_common/ccid_slot_fsm.c
+++ b/ccid_common/ccid_slot_fsm.c
@@ -172,7 +172,7 @@
 		tpdu = data;
 		LOGPCS(cs, LOGL_DEBUG, "%s(event=%d, data=%s)\n", __func__, event,
 			msgb_hexdump(tpdu));
-		resp = ccid_gen_data_block(cs, ss->seq, CCID_CMD_STATUS_OK, 0, msgb_l2(tpdu), msgb_l2len(tpdu));
+		resp = ccid_gen_data_block(cs, ss->seq, CCID_CMD_STATUS_OK, 0, msgb_l4(tpdu), msgb_l4len(tpdu));
 		ccid_slot_send_unbusy(cs, resp);
 		msgb_free(tpdu);
 		cs->event = 0;
diff --git a/ccid_common/iso7816_fsm.c b/ccid_common/iso7816_fsm.c
index c76d97d..2796d30 100644
--- a/ccid_common/iso7816_fsm.c
+++ b/ccid_common/iso7816_fsm.c
@@ -1175,9 +1175,13 @@
 		/* start transmission of a TPDU by sending the 5-byte header */
 		tfp->tpdu = (struct msgb *)data;
 		OSMO_ASSERT(msgb_length(tfp->tpdu) >= sizeof(*tpduh));
+		/* l2h = after the 5byte header */
 		tfp->tpdu->l2h = msgb_data(tfp->tpdu) + sizeof(*tpduh);
+		/* l4h = where we start to receive from the card */
+		tfp->tpdu->l4h = msgb_l2(tfp->tpdu) + msgb_l2len(tfp->tpdu);
 		if (msgb_l2len(tfp->tpdu)) {
 			tfp->is_command = true;
+			/* l3h = used as 'next byte to write' pointer */
 			tfp->tpdu->l3h = tfp->tpdu->l2h; /* next tx byte == first byte of body */
 		} else
 			tfp->is_command = false;

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Gerrit-Project: osmo-ccid-firmware
Gerrit-Branch: master
Gerrit-Change-Id: Ie3fc7437d39dc330b9f2b7d7960ad2560b6be4b7
Gerrit-Change-Number: 19460
Gerrit-PatchSet: 1
Gerrit-Owner: laforge <laforge at osmocom.org>
Gerrit-Reviewer: Jenkins Builder
Gerrit-Reviewer: laforge <laforge at osmocom.org>
Gerrit-MessageType: merged
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