[SRU][T][PATCH v2 1/3] net: Add ndo_gso_check
Daniel Axtens
daniel.axtens at canonical.com
Mon Feb 26 01:55:59 UTC 2018
From: Tom Herbert <therbert at google.com>
BugLink: https://bugs.launchpad.net/bugs/1715519
CVE-2018-1000026
Add ndo_gso_check which a device can define to indicate whether is
is capable of doing GSO on a packet. This funciton would be called from
the stack to determine whether software GSO is needed to be done. A
driver should populate this function if it advertises GSO types for
which there are combinations that it wouldn't be able to handle. For
instance a device that performs UDP tunneling might only implement
support for transparent Ethernet bridging type of inner packets
or might have limitations on lengths of inner headers.
Signed-off-by: Tom Herbert <therbert at google.com>
Signed-off-by: David S. Miller <davem at davemloft.net>
(backported from commit 04ffcb255f22a2a988ce7393e6e72f6eb3fcb7aa)
Signed-off-by: Daniel Axtens <daniel.axtens at canonical.com>
---
drivers/net/macvtap.c | 2 +-
drivers/net/xen-netfront.c | 2 +-
include/linux/netdevice.h | 12 +++++++++++-
net/core/dev.c | 2 +-
4 files changed, 14 insertions(+), 4 deletions(-)
diff --git a/drivers/net/macvtap.c b/drivers/net/macvtap.c
index 66a8710bbcc3..0c1699e0fe11 100644
--- a/drivers/net/macvtap.c
+++ b/drivers/net/macvtap.c
@@ -292,7 +292,7 @@ static int macvtap_forward(struct net_device *dev, struct sk_buff *skb)
*/
if (q->flags & IFF_VNET_HDR)
features |= vlan->tap_features;
- if (netif_needs_gso(skb, features)) {
+ if (netif_needs_gso(dev, skb, features)) {
struct sk_buff *segs = __skb_gso_segment(skb, features, false);
if (IS_ERR(segs))
diff --git a/drivers/net/xen-netfront.c b/drivers/net/xen-netfront.c
index d5d7cd397b89..d28a91e43e45 100644
--- a/drivers/net/xen-netfront.c
+++ b/drivers/net/xen-netfront.c
@@ -581,7 +581,7 @@ static int xennet_start_xmit(struct sk_buff *skb, struct net_device *dev)
if (unlikely(!netif_carrier_ok(dev) ||
(slots > 1 && !xennet_can_sg(dev)) ||
- netif_needs_gso(skb, netif_skb_features(skb)))) {
+ netif_needs_gso(dev, skb, netif_skb_features(skb)))) {
spin_unlock_irqrestore(&np->tx_lock, flags);
goto drop;
}
diff --git a/include/linux/netdevice.h b/include/linux/netdevice.h
index 42d16122fb8f..21ced47b9664 100644
--- a/include/linux/netdevice.h
+++ b/include/linux/netdevice.h
@@ -985,6 +985,12 @@ typedef u16 (*select_queue_fallback_t)(struct net_device *dev,
* Callback to use for xmit over the accelerated station. This
* is used in place of ndo_start_xmit on accelerated net
* devices.
+ * bool (*ndo_gso_check) (struct sk_buff *skb,
+ * struct net_device *dev);
+ * Called by core transmit path to determine if device is capable of
+ * performing GSO on a packet. The device returns true if it is
+ * able to GSO the packet, false otherwise. If the return value is
+ * false the stack will do software GSO.
*/
struct net_device_ops {
int (*ndo_init)(struct net_device *dev);
@@ -1133,6 +1139,8 @@ struct net_device_ops {
struct net_device *dev,
void *priv);
int (*ndo_get_lock_subclass)(struct net_device *dev);
+ bool (*ndo_gso_check) (struct sk_buff *skb,
+ struct net_device *dev);
};
/*
@@ -3088,10 +3096,12 @@ static inline bool skb_gso_ok(struct sk_buff *skb, netdev_features_t features)
(!skb_has_frag_list(skb) || (features & NETIF_F_FRAGLIST));
}
-static inline bool netif_needs_gso(struct sk_buff *skb,
+static inline bool netif_needs_gso(struct net_device *dev, struct sk_buff *skb,
netdev_features_t features)
{
return skb_is_gso(skb) && (!skb_gso_ok(skb, features) ||
+ (dev->netdev_ops->ndo_gso_check &&
+ !dev->netdev_ops->ndo_gso_check(skb, dev)) ||
unlikely((skb->ip_summed != CHECKSUM_PARTIAL) &&
(skb->ip_summed != CHECKSUM_UNNECESSARY)));
}
diff --git a/net/core/dev.c b/net/core/dev.c
index 7775de79ce86..1d37e93ad23c 100644
--- a/net/core/dev.c
+++ b/net/core/dev.c
@@ -2575,7 +2575,7 @@ int dev_hard_start_xmit(struct sk_buff *skb, struct net_device *dev,
if (skb->encapsulation)
features &= dev->hw_enc_features;
- if (netif_needs_gso(skb, features)) {
+ if (netif_needs_gso(dev, skb, features)) {
if (unlikely(dev_gso_segment(skb, features)))
goto out_kfree_skb;
if (skb->next)
--
2.14.1
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