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can: do not copy the payload of RTR frames

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The actual payload length of the CAN Remote Transmission Request (RTR)
frames is always 0, i.e. no payload is transmitted on the wire.
However, those RTR frames still use the DLC to indicate the length of
the requested frame.

For this reason, it is incorrect to copy the payload of RTR frames
(the payload buffer would only contain garbage data). This patch
encapsulates the payload copy in a check toward the RTR flag.

Link: https://lore.kernel.org/all/20211207121531.42941-4-mailhol.vincent@wanadoo.fr
Cc: Yasushi SHOJI <yashi@spacecubics.com>
Tested-by: Yasushi SHOJI <yashi@spacecubics.com>
Signed-off-by: Vincent Mailhol <mailhol.vincent@wanadoo.fr>
Signed-off-by: Marc Kleine-Budde <mkl@pengutronix.de>
This commit is contained in:
Vincent Mailhol 2021-12-07 21:15:29 +09:00 committed by Marc Kleine-Budde
parent 0b0ce2c677
commit f68eafeb97
3 changed files with 14 additions and 12 deletions
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15
drivers/net/can/pch_can.c
View File

@ -677,16 +677,17 @@ static int pch_can_rx_normal(struct net_device *ndev, u32 obj_num, int quota)
cf->can_id = id;
}
if (id2 & PCH_ID2_DIR)
cf->can_id |= CAN_RTR_FLAG;
cf->len = can_cc_dlc2len((ioread32(&priv->regs->
ifregs[0].mcont)) & 0xF);
for (i = 0; i < cf->len; i += 2) {
data_reg = ioread16(&priv->regs->ifregs[0].data[i / 2]);
cf->data[i] = data_reg;
cf->data[i + 1] = data_reg >> 8;
if (id2 & PCH_ID2_DIR) {
cf->can_id |= CAN_RTR_FLAG;
} else {
for (i = 0; i < cf->len; i += 2) {
data_reg = ioread16(&priv->regs->ifregs[0].data[i / 2]);
cf->data[i] = data_reg;
cf->data[i + 1] = data_reg >> 8;
}
}
rcv_pkts++;

3
drivers/net/can/spi/mcp251x.c
View File

@ -730,7 +730,8 @@ static void mcp251x_hw_rx(struct spi_device *spi, int buf_idx)
}
/* Data length */
frame->len = can_cc_dlc2len(buf[RXBDLC_OFF] & RXBDLC_LEN_MASK);
memcpy(frame->data, buf + RXBDAT_OFF, frame->len);
if (!(frame->can_id & CAN_RTR_FLAG))
memcpy(frame->data, buf + RXBDAT_OFF, frame->len);
priv->net->stats.rx_packets++;
priv->net->stats.rx_bytes += frame->len;

8
drivers/net/can/usb/mcba_usb.c
View File

@ -450,12 +450,12 @@ static void mcba_usb_process_can(struct mcba_priv *priv,
cf->can_id = (sid & 0xffe0) >> 5;
}
if (msg->dlc & MCBA_DLC_RTR_MASK)
cf->can_id |= CAN_RTR_FLAG;
cf->len = can_cc_dlc2len(msg->dlc & MCBA_DLC_MASK);
memcpy(cf->data, msg->data, cf->len);
if (msg->dlc & MCBA_DLC_RTR_MASK)
cf->can_id |= CAN_RTR_FLAG;
else
memcpy(cf->data, msg->data, cf->len);
stats->rx_packets++;
stats->rx_bytes += cf->len;