Currently there are a number of error paths in the lowpan_rcv function that
free the skb before returning, this patch simplifies the receive path by
ensuring that the skb is only freed from this function.
Signed-off-by: Martin Townsend <martin.townsend@xxxxxxxxxx>
---
include/net/6lowpan.h | 2 +-
net/6lowpan/iphc.c | 27 +++++++++++++++------------
net/bluetooth/6lowpan.c | 12 ++++++++----
net/ieee802154/6lowpan_rtnl.c | 12 ++++++------
4 files changed, 30 insertions(+), 23 deletions(-)
diff --git a/include/net/6lowpan.h b/include/net/6lowpan.h
index d184df1..883e7a2 100644
--- a/include/net/6lowpan.h
+++ b/include/net/6lowpan.h
@@ -374,7 +374,7 @@ lowpan_uncompress_size(const struct sk_buff *skb, u16 *dgram_offset)
typedef int (*skb_delivery_cb)(struct sk_buff *skb, struct net_device *dev);
-int lowpan_process_data(struct sk_buff *skb, struct net_device *dev,
+int lowpan_process_data(struct sk_buff **skb_inout, struct net_device *dev,
const u8 *saddr, const u8 saddr_type, const u8 saddr_len,
const u8 *daddr, const u8 daddr_type, const u8 daddr_len,
u8 iphc0, u8 iphc1, skb_delivery_cb skb_deliver);
diff --git a/net/6lowpan/iphc.c b/net/6lowpan/iphc.c
index 142eef5..eca24bf 100644
--- a/net/6lowpan/iphc.c
+++ b/net/6lowpan/iphc.c
@@ -179,11 +179,11 @@ static int skb_deliver(struct sk_buff *skb, struct ipv6hdr *hdr,
new = skb_copy_expand(skb, sizeof(struct ipv6hdr), skb_tailroom(skb),
GFP_ATOMIC);
- kfree_skb(skb);
-
if (!new)
return -ENOMEM;
+ kfree_skb(skb);
+
skb_push(new, sizeof(struct ipv6hdr));
skb_reset_network_header(new);
skb_copy_to_linear_data(new, hdr, sizeof(struct ipv6hdr));
@@ -196,6 +196,8 @@ static int skb_deliver(struct sk_buff *skb, struct ipv6hdr *hdr,
new->data, new->len);
stat = deliver_skb(new, dev);
+ if (stat < 0)
+ stat = NET_RX_DROP;
kfree_skb(new);
@@ -332,7 +334,7 @@ err:
/* TTL uncompression values */
static const u8 lowpan_ttl_values[] = { 0, 1, 64, 255 };
-int lowpan_process_data(struct sk_buff *skb, struct net_device *dev,
+int lowpan_process_data(struct sk_buff **skb_inout, struct net_device *dev,
const u8 *saddr, const u8 saddr_type, const u8 saddr_len,
const u8 *daddr, const u8 daddr_type, const u8 daddr_len,
u8 iphc0, u8 iphc1, skb_delivery_cb deliver_skb)
@@ -340,6 +342,8 @@ int lowpan_process_data(struct sk_buff *skb, struct net_device *dev,
struct ipv6hdr hdr = {};
u8 tmp, num_context = 0;
int err;
+ int err_ret = -EINVAL;
+ struct sk_buff *skb = *skb_inout;
raw_dump_table(__func__, "raw skb data dump uncompressed",
skb->data, skb->len);
@@ -460,7 +464,6 @@ int lowpan_process_data(struct sk_buff *skb, struct net_device *dev,
/* UDP data uncompression */
if (iphc0 & LOWPAN_IPHC_NH_C) {
struct udphdr uh;
- struct sk_buff *new;
if (uncompress_udp_header(skb, &uh))
goto drop;
@@ -468,14 +471,15 @@ int lowpan_process_data(struct sk_buff *skb, struct net_device *dev,
/* replace the compressed UDP head by the uncompressed UDP
* header
*/
- new = skb_copy_expand(skb, sizeof(struct udphdr),
+ skb = skb_copy_expand(skb, sizeof(struct udphdr),
skb_tailroom(skb), GFP_ATOMIC);
- kfree_skb(skb);
-
- if (!new)
- return -ENOMEM;
+ if (!skb) {
+ err_ret = -ENOMEM;
+ goto drop;
+ }
- skb = new;
+ kfree_skb(*skb_inout);
+ *skb_inout = skb;
skb_push(skb, sizeof(struct udphdr));
skb_reset_transport_header(skb);
@@ -502,8 +506,7 @@ int lowpan_process_data(struct sk_buff *skb, struct net_device *dev,
return skb_deliver(skb, &hdr, dev, deliver_skb);
drop:
- kfree_skb(skb);
- return -EINVAL;
+ return err_ret;
}
EXPORT_SYMBOL_GPL(lowpan_process_data);
diff --git a/net/bluetooth/6lowpan.c b/net/bluetooth/6lowpan.c
index 206b65c..f5f7ee0 100644
--- a/net/bluetooth/6lowpan.c
+++ b/net/bluetooth/6lowpan.c
@@ -215,7 +215,7 @@ static int give_skb_to_upper(struct sk_buff *skb, struct net_device *dev)
return ret;
}
-static int process_data(struct sk_buff *skb, struct net_device *netdev,
+static int process_data(struct sk_buff **skb_inout, struct net_device *netdev,
struct l2cap_chan *chan)
{
const u8 *saddr, *daddr;
@@ -223,6 +223,7 @@ static int process_data(struct sk_buff *skb, struct net_device *netdev,
struct lowpan_dev *dev;
struct lowpan_peer *peer;
unsigned long flags;
+ struct sk_buff *skb = *skb_inout;
dev = lowpan_dev(netdev);
@@ -245,13 +246,12 @@ static int process_data(struct sk_buff *skb, struct net_device *netdev,
if (lowpan_fetch_skb_u8(skb, &iphc1))
goto drop;
- return lowpan_process_data(skb, netdev,
+ return lowpan_process_data(skb_inout, netdev,
saddr, IEEE802154_ADDR_LONG, EUI64_ADDR_LEN,
daddr, IEEE802154_ADDR_LONG, EUI64_ADDR_LEN,
iphc0, iphc1, give_skb_to_upper);
drop:
- kfree_skb(skb);
return -EINVAL;
}
@@ -300,7 +300,11 @@ static int recv_pkt(struct sk_buff *skb, struct net_device *dev,
if (!local_skb)
goto drop;
- ret = process_data(local_skb, dev, chan);
+ ret = process_data(&local_skb, dev, chan);
+ if (ret < 0) {
+ kfree_skb(local_skb);
+ goto drop;
+ }
if (ret != NET_RX_SUCCESS)
goto drop;
diff --git a/net/ieee802154/6lowpan_rtnl.c b/net/ieee802154/6lowpan_rtnl.c
index 6591d27..fdb6c10 100644
--- a/net/ieee802154/6lowpan_rtnl.c
+++ b/net/ieee802154/6lowpan_rtnl.c
@@ -167,11 +167,12 @@ static int lowpan_give_skb_to_devices(struct sk_buff *skb,
return stat;
}
-static int process_data(struct sk_buff *skb, const struct ieee802154_hdr *hdr)
+static int process_data(struct sk_buff **skb_inout, const struct ieee802154_hdr *hdr)
{
u8 iphc0, iphc1;
struct ieee802154_addr_sa sa, da;
void *sap, *dap;
+ struct sk_buff *skb = *skb_inout;
raw_dump_table(__func__, "raw skb data dump", skb->data, skb->len);
/* at least two bytes will be used for the encoding */
@@ -197,13 +198,12 @@ static int process_data(struct sk_buff *skb, const struct ieee802154_hdr *hdr)
else
dap = &da.hwaddr;
- return lowpan_process_data(skb, skb->dev, sap, sa.addr_type,
+ return lowpan_process_data(skb_inout, skb->dev, sap, sa.addr_type,
IEEE802154_ADDR_LEN, dap, da.addr_type,
IEEE802154_ADDR_LEN, iphc0, iphc1,
lowpan_give_skb_to_devices);
drop:
- kfree_skb(skb);
return -EINVAL;
}
@@ -490,14 +490,14 @@ static int lowpan_rcv(struct sk_buff *skb, struct net_device *dev,
} else {
switch (skb->data[0] & 0xe0) {
case LOWPAN_DISPATCH_IPHC: /* ipv6 datagram */
- ret = process_data(skb, &hdr);
+ ret = process_data(&skb, &hdr);
if (ret == NET_RX_DROP)
goto drop;
break;
case LOWPAN_DISPATCH_FRAG1: /* first fragment header */
ret = lowpan_frag_rcv(skb, LOWPAN_DISPATCH_FRAG1);
if (ret == 1) {
- ret = process_data(skb, &hdr);
+ ret = process_data(&skb, &hdr);
if (ret == NET_RX_DROP)
goto drop;
}
@@ -505,7 +505,7 @@ static int lowpan_rcv(struct sk_buff *skb, struct net_device *dev,
case LOWPAN_DISPATCH_FRAGN: /* next fragments headers */
ret = lowpan_frag_rcv(skb, LOWPAN_DISPATCH_FRAGN);
if (ret == 1) {
- ret = process_data(skb, &hdr);
+ ret = process_data(&skb, &hdr);
if (ret == NET_RX_DROP)
goto drop;
}
--
1.9.1
--
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