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| author | Oliver Hartkopp <oliver@hartkopp.net> | 2009-12-12 05:13:21 +0100 |
|---|---|---|
| committer | David S. Miller <davem@davemloft.net> | 2009-12-14 04:47:42 +0100 |
| commit | c7cd606f60e7679c7f9eee7010f02a6f000209c1 (patch) | |
| tree | 31c19fd7617ede807757b0ae5c29d218587dc43f /drivers/net/can/mcp251x.c | |
| parent | net: Fix userspace RTM_NEWLINK notifications. (diff) | |
| download | linux-c7cd606f60e7679c7f9eee7010f02a6f000209c1.tar.xz linux-c7cd606f60e7679c7f9eee7010f02a6f000209c1.zip | |
can: Fix data length code handling in rx path
A valid CAN dataframe can have a data length code (DLC) of 0 .. 8 data bytes.
When reading the CAN controllers register the 4-bit value may contain values
from 0 .. 15 which may exceed the reserved space in the socket buffer!
The ISO 11898-1 Chapter 8.4.2.3 (DLC field) says that register values > 8
should be reduced to 8 without any error reporting or frame drop.
This patch introduces a new helper macro to cast a given 4-bit data length
code (dlc) to __u8 and ensure the DLC value to be max. 8 bytes.
The different handlings in the rx path of the CAN netdevice drivers are fixed.
Signed-off-by: Oliver Hartkopp <oliver@hartkopp.net>
Signed-off-by: Wolfgang Grandegger <wg@grandegger.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
Diffstat (limited to 'drivers/net/can/mcp251x.c')
| -rw-r--r-- | drivers/net/can/mcp251x.c | 13 |
1 files changed, 3 insertions, 10 deletions
diff --git a/drivers/net/can/mcp251x.c b/drivers/net/can/mcp251x.c index 78b1b69b2921..9c5a1537939c 100644 --- a/drivers/net/can/mcp251x.c +++ b/drivers/net/can/mcp251x.c @@ -403,9 +403,8 @@ static void mcp251x_hw_rx_frame(struct spi_device *spi, u8 *buf, for (i = 1; i < RXBDAT_OFF; i++) buf[i] = mcp251x_read_reg(spi, RXBCTRL(buf_idx) + i); - len = buf[RXBDLC_OFF] & RXBDLC_LEN_MASK; - if (len > 8) - len = 8; + + len = get_can_dlc(buf[RXBDLC_OFF] & RXBDLC_LEN_MASK); for (; i < (RXBDAT_OFF + len); i++) buf[i] = mcp251x_read_reg(spi, RXBCTRL(buf_idx) + i); } else { @@ -455,13 +454,7 @@ static void mcp251x_hw_rx(struct spi_device *spi, int buf_idx) (buf[RXBSIDL_OFF] >> RXBSIDL_SHIFT); } /* Data length */ - frame->can_dlc = buf[RXBDLC_OFF] & RXBDLC_LEN_MASK; - if (frame->can_dlc > 8) { - dev_warn(&spi->dev, "invalid frame recevied\n"); - priv->net->stats.rx_errors++; - dev_kfree_skb(skb); - return; - } + frame->can_dlc = get_can_dlc(buf[RXBDLC_OFF] & RXBDLC_LEN_MASK); memcpy(frame->data, buf + RXBDAT_OFF, frame->can_dlc); priv->net->stats.rx_packets++; |