[PATCH AUTOSEL 5.3 42/71] arcnet: provide a buffer big enough to actually receive packets

Sasha Levin
2019-10-01T17:01:19Z

From: Uwe Kleine-König <u.kleine-koenig@pengutronix.de>

[ Upstream commit 02a07046834e64970f3bcd87a422ac2b0adb80de ]

struct archdr is only big enough to hold the header of various types of
arcnet packets. So to provide enough space to hold the data read from
hardware provide a buffer large enough to hold a packet with maximal
size.

The problem was noticed by the stack protector which makes the kernel
oops.

Signed-off-by: Uwe Kleine-König <u.kleine-koenig@pengutronix.de>
Acked-by: Michael Grzeschik <m.grzeschik@pengutronix.de>
Signed-off-by: David S. Miller <davem@davemloft.net>
Signed-off-by: Sasha Levin <sashal@kernel.org>
---
drivers/net/arcnet/arcnet.c | 31 +++++++++++++++++--------------
1 file changed, 17 insertions(+), 14 deletions(-)

diff --git a/drivers/net/arcnet/arcnet.c b/drivers/net/arcnet/arcnet.c
index 8459115d9d4e5..553776cc1d29d 100644
--- a/drivers/net/arcnet/arcnet.c
+++ b/drivers/net/arcnet/arcnet.c
@@ -1063,31 +1063,34 @@ EXPORT_SYMBOL(arcnet_interrupt);
static void arcnet_rx(struct net_device *dev, int bufnum)
{
struct arcnet_local *lp = netdev_priv(dev);
- struct archdr pkt;
+ union {
+ struct archdr pkt;
+ char buf[512];
+ } rxdata;
struct arc_rfc1201 *soft;
int length, ofs;

- soft = &pkt.soft.rfc1201;
+ soft = &rxdata.pkt.soft.rfc1201;

- lp->hw.copy_from_card(dev, bufnum, 0, &pkt, ARC_HDR_SIZE);
- if (pkt.hard.offset[0]) {
- ofs = pkt.hard.offset[0];
+ lp->hw.copy_from_card(dev, bufnum, 0, &rxdata.pkt, ARC_HDR_SIZE);
+ if (rxdata.pkt.hard.offset[0]) {
+ ofs = rxdata.pkt.hard.offset[0];
length = 256 - ofs;
} else {
- ofs = pkt.hard.offset[1];
+ ofs = rxdata.pkt.hard.offset[1];
length = 512 - ofs;
}

/* get the full header, if possible */
- if (sizeof(pkt.soft) <= length) {
- lp->hw.copy_from_card(dev, bufnum, ofs, soft, sizeof(pkt.soft));
+ if (sizeof(rxdata.pkt.soft) <= length) {
+ lp->hw.copy_from_card(dev, bufnum, ofs, soft, sizeof(rxdata.pkt.soft));
} else {
- memset(&pkt.soft, 0, sizeof(pkt.soft));
+ memset(&rxdata.pkt.soft, 0, sizeof(rxdata.pkt.soft));
lp->hw.copy_from_card(dev, bufnum, ofs, soft, length);
}

arc_printk(D_DURING, dev, "Buffer #%d: received packet from %02Xh to %02Xh (%d+4 bytes)\n",
- bufnum, pkt.hard.source, pkt.hard.dest, length);
+ bufnum, rxdata.pkt.hard.source, rxdata.pkt.hard.dest, length);

dev->stats.rx_packets++;
dev->stats.rx_bytes += length + ARC_HDR_SIZE;
@@ -1096,13 +1099,13 @@ static void arcnet_rx(struct net_device *dev, int bufnum)
if (arc_proto_map[soft->proto]->is_ip) {
if (BUGLVL(D_PROTO)) {
struct ArcProto
- *oldp = arc_proto_map[lp->default_proto[pkt.hard.source]],
+ *oldp = arc_proto_map[lp->default_proto[rxdata.pkt.hard.source]],
*newp = arc_proto_map[soft->proto];

if (oldp != newp) {
arc_printk(D_PROTO, dev,
"got protocol %02Xh; encap for host %02Xh is now '%c' (was '%c')\n",
- soft->proto, pkt.hard.source,
+ soft->proto, rxdata.pkt.hard.source,
newp->suffix, oldp->suffix);
}
}
@@ -1111,10 +1114,10 @@ static void arcnet_rx(struct net_device *dev, int bufnum)
lp->default_proto[0] = soft->proto;

/* in striking contrast, the following isn't a hack. */
- lp->default_proto[pkt.hard.source] = soft->proto;
+ lp->default_proto[rxdata.pkt.hard.source] = soft->proto;
}
/* call the protocol-specific receiver. */
- arc_proto_map[soft->proto]->rx(dev, bufnum, &pkt, length);
+ arc_proto_map[soft->proto]->rx(dev, bufnum, &rxdata.pkt, length);
}

static void null_rx(struct net_device *dev, int bufnum,
--
2.20.1