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[media] cec: zero unused msg part after msg->len

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Ensure that the unused part of the msg array is zeroed. This is
required by CEC 2.0 when receiving shorter messages than expected.
In that case the remaining bytes are assumed to be 0.

There are no such CEC messages yet, but it is required to be future proof.

And since we're doing it for received messages, do it for transmitted
messages as well. It's unambiguous this way.

Signed-off-by: Hans Verkuil <hans.verkuil@cisco.com>
Signed-off-by: Mauro Carvalho Chehab <mchehab@s-opensource.com>
This commit is contained in:
Hans Verkuil 2016-07-17 05:16:40 -03:00 committed by Mauro Carvalho Chehab
parent 4eef404fd9
commit 045344c3c1
1 changed files with 2 additions and 0 deletions
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2
drivers/staging/media/cec/cec-adap.c
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@ -601,6 +601,7 @@ int cec_transmit_msg_fh(struct cec_adapter *adap, struct cec_msg *msg,
dprintk(1, "cec_transmit_msg: can't reply for poll msg\n"); dprintk(1, "cec_transmit_msg: can't reply for poll msg\n");
return -EINVAL; return -EINVAL;
} }
memset(msg->msg + msg->len, 0, sizeof(msg->msg) - msg->len);
if (msg->len == 1) { if (msg->len == 1) {
if (cec_msg_initiator(msg) != 0xf || if (cec_msg_initiator(msg) != 0xf ||
cec_msg_destination(msg) == 0xf) { cec_msg_destination(msg) == 0xf) {
@ -771,6 +772,7 @@ void cec_received_msg(struct cec_adapter *adap, struct cec_msg *msg)
msg->tx_status = 0; msg->tx_status = 0;
msg->tx_ts = 0; msg->tx_ts = 0;
msg->flags = 0; msg->flags = 0;
memset(msg->msg + msg->len, 0, sizeof(msg->msg) - msg->len);
mutex_lock(&adap->lock); mutex_lock(&adap->lock);
dprintk(2, "cec_received_msg: %*ph\n", msg->len, msg->msg); dprintk(2, "cec_received_msg: %*ph\n", msg->len, msg->msg);