| Message ID | 20200204230118.7877-1-mdf@kernel.org |
|---|---|
| State | Accepted |
| Delegated to: | David Miller |
| Headers | show |
| Series | net: ethernet: dec: tulip: Fix length mask in receive length calculation | expand |
From: Moritz Fischer <mdf@kernel.org> Date: Tue, 4 Feb 2020 15:01:18 -0800 > The receive frame length calculation uses a wrong mask to calculate the > length of the received frames. > > Per spec table 4-1 the length is contained in the FL (Frame Length) > field in bits 30:16. > > This didn't show up as an issue so far since frames were limited to > 1500 bytes which falls within the 11 bit window. > > Signed-off-by: Moritz Fischer <mdf@kernel.org> Applied, thanks.
diff --git a/drivers/net/ethernet/dec/tulip/de2104x.c b/drivers/net/ethernet/dec/tulip/de2104x.c index d305d1b24b0a..42b798a3fad4 100644 --- a/drivers/net/ethernet/dec/tulip/de2104x.c +++ b/drivers/net/ethernet/dec/tulip/de2104x.c @@ -417,7 +417,10 @@ static void de_rx (struct de_private *de) if (status & DescOwn) break; - len = ((status >> 16) & 0x7ff) - 4; + /* the length is actually a 15 bit value here according + * to Table 4-1 in the DE2104x spec so mask is 0x7fff + */ + len = ((status >> 16) & 0x7fff) - 4; mapping = de->rx_skb[rx_tail].mapping; if (unlikely(drop)) {
The receive frame length calculation uses a wrong mask to calculate the length of the received frames. Per spec table 4-1 the length is contained in the FL (Frame Length) field in bits 30:16. This didn't show up as an issue so far since frames were limited to 1500 bytes which falls within the 11 bit window. Signed-off-by: Moritz Fischer <mdf@kernel.org> --- drivers/net/ethernet/dec/tulip/de2104x.c | 5 ++++- 1 file changed, 4 insertions(+), 1 deletion(-)