[PATCH 5.12 280/296] net: hsr: fix mac_len checks

Greg Kroah-Hartman
2021-05-31T16:50:30Z

From: George McCollister <george.mccollister@gmail.com>

[ Upstream commit 48b491a5cc74333c4a6a82fe21cea42c055a3b0b ]

Commit 2e9f60932a2c ("net: hsr: check skb can contain struct hsr_ethhdr
in fill_frame_info") added the following which resulted in -EINVAL
always being returned:
if (skb->mac_len < sizeof(struct hsr_ethhdr))
return -EINVAL;

mac_len was not being set correctly so this check completely broke
HSR/PRP since it was always 14, not 20.

Set mac_len correctly and modify the mac_len checks to test in the
correct places since sometimes it is legitimately 14.

Fixes: 2e9f60932a2c ("net: hsr: check skb can contain struct hsr_ethhdr in fill_frame_info")
Signed-off-by: George McCollister <george.mccollister@gmail.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
Signed-off-by: Sasha Levin <sashal@kernel.org>
---
net/hsr/hsr_device.c | 2 ++
net/hsr/hsr_forward.c | 30 +++++++++++++++++++++---------
net/hsr/hsr_forward.h | 8 ++++----
net/hsr/hsr_main.h | 4 ++--
net/hsr/hsr_slave.c | 11 +++++------
5 files changed, 34 insertions(+), 21 deletions(-)

diff --git a/net/hsr/hsr_device.c b/net/hsr/hsr_device.c
index bfcdc75fc01e..26c32407f029 100644
--- a/net/hsr/hsr_device.c
+++ b/net/hsr/hsr_device.c
@@ -218,6 +218,7 @@ static netdev_tx_t hsr_dev_xmit(struct sk_buff *skb, struct net_device *dev)
if (master) {
skb->dev = master->dev;
skb_reset_mac_header(skb);
+ skb_reset_mac_len(skb);
hsr_forward_skb(skb, master);
} else {
atomic_long_inc(&dev->tx_dropped);
@@ -259,6 +260,7 @@ static struct sk_buff *hsr_init_skb(struct hsr_port *master)
goto out;

skb_reset_mac_header(skb);
+ skb_reset_mac_len(skb);
skb_reset_network_header(skb);
skb_reset_transport_header(skb);

diff --git a/net/hsr/hsr_forward.c b/net/hsr/hsr_forward.c
index 6852e9bccf5b..ceb8afb2a62f 100644
--- a/net/hsr/hsr_forward.c
+++ b/net/hsr/hsr_forward.c
@@ -474,8 +474,8 @@ static void handle_std_frame(struct sk_buff *skb,
}
}

-void hsr_fill_frame_info(__be16 proto, struct sk_buff *skb,
- struct hsr_frame_info *frame)
+int hsr_fill_frame_info(__be16 proto, struct sk_buff *skb,
+ struct hsr_frame_info *frame)
{
struct hsr_port *port = frame->port_rcv;
struct hsr_priv *hsr = port->hsr;
@@ -483,20 +483,26 @@ void hsr_fill_frame_info(__be16 proto, struct sk_buff *skb,
/* HSRv0 supervisory frames double as a tag so treat them as tagged. */
if ((!hsr->prot_version && proto == htons(ETH_P_PRP)) ||
proto == htons(ETH_P_HSR)) {
+ /* Check if skb contains hsr_ethhdr */
+ if (skb->mac_len < sizeof(struct hsr_ethhdr))
+ return -EINVAL;
+
/* HSR tagged frame :- Data or Supervision */
frame->skb_std = NULL;
frame->skb_prp = NULL;
frame->skb_hsr = skb;
frame->sequence_nr = hsr_get_skb_sequence_nr(skb);
- return;
+ return 0;
}

/* Standard frame or PRP from master port */
handle_std_frame(skb, frame);
+
+ return 0;
}

-void prp_fill_frame_info(__be16 proto, struct sk_buff *skb,
- struct hsr_frame_info *frame)
+int prp_fill_frame_info(__be16 proto, struct sk_buff *skb,
+ struct hsr_frame_info *frame)
{
/* Supervision frame */
struct prp_rct *rct = skb_get_PRP_rct(skb);
@@ -507,9 +513,11 @@ void prp_fill_frame_info(__be16 proto, struct sk_buff *skb,
frame->skb_std = NULL;
frame->skb_prp = skb;
frame->sequence_nr = prp_get_skb_sequence_nr(rct);
- return;
+ return 0;
}
handle_std_frame(skb, frame);
+
+ return 0;
}

static int fill_frame_info(struct hsr_frame_info *frame,
@@ -519,9 +527,10 @@ static int fill_frame_info(struct hsr_frame_info *frame,
struct hsr_vlan_ethhdr *vlan_hdr;
struct ethhdr *ethhdr;
__be16 proto;
+ int ret;

- /* Check if skb contains hsr_ethhdr */
- if (skb->mac_len < sizeof(struct hsr_ethhdr))
+ /* Check if skb contains ethhdr */
+ if (skb->mac_len < sizeof(struct ethhdr))
return -EINVAL;

memset(frame, 0, sizeof(*frame));
@@ -548,7 +557,10 @@ static int fill_frame_info(struct hsr_frame_info *frame,

frame->is_from_san = false;
frame->port_rcv = port;
- hsr->proto_ops->fill_frame_info(proto, skb, frame);
+ ret = hsr->proto_ops->fill_frame_info(proto, skb, frame);
+ if (ret)
+ return ret;
+
check_local_dest(port->hsr, skb, frame);

return 0;
diff --git a/net/hsr/hsr_forward.h b/net/hsr/hsr_forward.h
index b6acaafa83fc..206636750b30 100644
--- a/net/hsr/hsr_forward.h
+++ b/net/hsr/hsr_forward.h
@@ -24,8 +24,8 @@ struct sk_buff *prp_get_untagged_frame(struct hsr_frame_info *frame,
struct hsr_port *port);
bool prp_drop_frame(struct hsr_frame_info *frame, struct hsr_port *port);
bool hsr_drop_frame(struct hsr_frame_info *frame, struct hsr_port *port);
-void prp_fill_frame_info(__be16 proto, struct sk_buff *skb,
- struct hsr_frame_info *frame);
-void hsr_fill_frame_info(__be16 proto, struct sk_buff *skb,
- struct hsr_frame_info *frame);
+int prp_fill_frame_info(__be16 proto, struct sk_buff *skb,
+ struct hsr_frame_info *frame);
+int hsr_fill_frame_info(__be16 proto, struct sk_buff *skb,
+ struct hsr_frame_info *frame);
#endif /* __HSR_FORWARD_H */
diff --git a/net/hsr/hsr_main.h b/net/hsr/hsr_main.h
index 8f264672b70b..53d1f7a82463 100644
--- a/net/hsr/hsr_main.h
+++ b/net/hsr/hsr_main.h
@@ -186,8 +186,8 @@ struct hsr_proto_ops {
struct hsr_port *port);
struct sk_buff * (*create_tagged_frame)(struct hsr_frame_info *frame,
struct hsr_port *port);
- void (*fill_frame_info)(__be16 proto, struct sk_buff *skb,
- struct hsr_frame_info *frame);
+ int (*fill_frame_info)(__be16 proto, struct sk_buff *skb,
+ struct hsr_frame_info *frame);
bool (*invalid_dan_ingress_frame)(__be16 protocol);
void (*update_san_info)(struct hsr_node *node, bool is_sup);
};
diff --git a/net/hsr/hsr_slave.c b/net/hsr/hsr_slave.c
index c5227d42faf5..b70e6bbf6021 100644
--- a/net/hsr/hsr_slave.c
+++ b/net/hsr/hsr_slave.c
@@ -60,12 +60,11 @@ static rx_handler_result_t hsr_handle_frame(struct sk_buff **pskb)
goto finish_pass;

skb_push(skb, ETH_HLEN);
-
- if (skb_mac_header(skb) != skb->data) {
- WARN_ONCE(1, "%s:%d: Malformed frame at source port %s)\n",
- __func__, __LINE__, port->dev->name);
- goto finish_consume;
- }
+ skb_reset_mac_header(skb);
+ if ((!hsr->prot_version && protocol == htons(ETH_P_PRP)) ||
+ protocol == htons(ETH_P_HSR))
+ skb_set_network_header(skb, ETH_HLEN + HSR_HLEN);
+ skb_reset_mac_len(skb);

hsr_forward_skb(skb, port);

--
2.30.2