* [PATCH net 1/5] vxlan: re-fetch eth header after route_shortcircuit()
[not found] <20260723144249.759100-1-edumazet@google.com>
@ 2026-07-23 14:42 ` Eric Dumazet
2026-07-23 16:37 ` Vadim Fedorenko
2026-07-23 14:42 ` [PATCH net 2/5] vxlan: unclone skb head before modifying eth header in route_shortcircuit() Eric Dumazet
` (3 subsequent siblings)
4 siblings, 1 reply; 10+ messages in thread
From: Eric Dumazet @ 2026-07-23 14:42 UTC (permalink / raw)
To: David S . Miller, Jakub Kicinski, Paolo Abeni
Cc: Simon Horman, Ido Schimmel, Andrew Lunn, netdev, eric.dumazet,
Eric Dumazet, stable
Before route_shortcircuit(), the eth header pointer is cached from eth_hdr(skb).
Inside route_shortcircuit(), pskb_may_pull() can be called, which may
reallocate skb->head.
In this case, returning to vxlan_xmit() leaves the cached eth pointer pointing to
freed memory, leading to a use-after-free when dereferencing eth->h_dest.
Fix this by updating eth = eth_hdr(skb) after calling route_shortcircuit().
Fixes: ae8840825605 ("VXLAN: Allow L2 redirection with L3 switching")
Cc: stable@vger.kernel.org
Signed-off-by: Eric Dumazet <edumazet@google.com>
---
drivers/net/vxlan/vxlan_core.c | 1 +
1 file changed, 1 insertion(+)
diff --git a/drivers/net/vxlan/vxlan_core.c b/drivers/net/vxlan/vxlan_core.c
index 67c367cc566233e809b0f70e0d939dd1c1ac0d9f..9060a1259ac283d4db4b7a854ce74203496e9313 100644
--- a/drivers/net/vxlan/vxlan_core.c
+++ b/drivers/net/vxlan/vxlan_core.c
@@ -2796,6 +2796,7 @@ static netdev_tx_t vxlan_xmit(struct sk_buff *skb, struct net_device *dev)
(ntohs(eth->h_proto) == ETH_P_IP ||
ntohs(eth->h_proto) == ETH_P_IPV6)) {
did_rsc = route_shortcircuit(dev, skb);
+ eth = eth_hdr(skb);
if (did_rsc)
f = vxlan_find_mac_tx(vxlan, eth->h_dest, vni);
}
--
2.55.0.229.g6434b31f56-goog
^ permalink raw reply related [flat|nested] 10+ messages in thread* Re: [PATCH net 1/5] vxlan: re-fetch eth header after route_shortcircuit()
2026-07-23 14:42 ` [PATCH net 1/5] vxlan: re-fetch eth header after route_shortcircuit() Eric Dumazet
@ 2026-07-23 16:37 ` Vadim Fedorenko
0 siblings, 0 replies; 10+ messages in thread
From: Vadim Fedorenko @ 2026-07-23 16:37 UTC (permalink / raw)
To: Eric Dumazet, David S . Miller, Jakub Kicinski, Paolo Abeni
Cc: Simon Horman, Ido Schimmel, Andrew Lunn, netdev, eric.dumazet,
stable
On 23/07/2026 15:42, Eric Dumazet wrote:
> Before route_shortcircuit(), the eth header pointer is cached from eth_hdr(skb).
>
> Inside route_shortcircuit(), pskb_may_pull() can be called, which may
> reallocate skb->head.
>
> In this case, returning to vxlan_xmit() leaves the cached eth pointer pointing to
> freed memory, leading to a use-after-free when dereferencing eth->h_dest.
>
> Fix this by updating eth = eth_hdr(skb) after calling route_shortcircuit().
>
> Fixes: ae8840825605 ("VXLAN: Allow L2 redirection with L3 switching")
> Cc: stable@vger.kernel.org
> Signed-off-by: Eric Dumazet <edumazet@google.com>
> ---
> drivers/net/vxlan/vxlan_core.c | 1 +
> 1 file changed, 1 insertion(+)
>
> diff --git a/drivers/net/vxlan/vxlan_core.c b/drivers/net/vxlan/vxlan_core.c
> index 67c367cc566233e809b0f70e0d939dd1c1ac0d9f..9060a1259ac283d4db4b7a854ce74203496e9313 100644
> --- a/drivers/net/vxlan/vxlan_core.c
> +++ b/drivers/net/vxlan/vxlan_core.c
> @@ -2796,6 +2796,7 @@ static netdev_tx_t vxlan_xmit(struct sk_buff *skb, struct net_device *dev)
> (ntohs(eth->h_proto) == ETH_P_IP ||
> ntohs(eth->h_proto) == ETH_P_IPV6)) {
> did_rsc = route_shortcircuit(dev, skb);
> + eth = eth_hdr(skb);
> if (did_rsc)
> f = vxlan_find_mac_tx(vxlan, eth->h_dest, vni);
> }
Reviewed-by: Vadim Fedorenko <vadim.fedorenko@linux.dev>
^ permalink raw reply [flat|nested] 10+ messages in thread
* [PATCH net 2/5] vxlan: unclone skb head before modifying eth header in route_shortcircuit()
[not found] <20260723144249.759100-1-edumazet@google.com>
2026-07-23 14:42 ` [PATCH net 1/5] vxlan: re-fetch eth header after route_shortcircuit() Eric Dumazet
@ 2026-07-23 14:42 ` Eric Dumazet
2026-07-23 14:42 ` [PATCH net 3/5] vxlan: use neigh_ha_snapshot() " Eric Dumazet
` (2 subsequent siblings)
4 siblings, 0 replies; 10+ messages in thread
From: Eric Dumazet @ 2026-07-23 14:42 UTC (permalink / raw)
To: David S . Miller, Jakub Kicinski, Paolo Abeni
Cc: Simon Horman, Ido Schimmel, Andrew Lunn, netdev, eric.dumazet,
Eric Dumazet, stable
When route_shortcircuit() performs L3 short-circuit routing, it modifies
the Ethernet header of the skb in-place:
memcpy(eth_hdr(skb)->h_source, eth_hdr(skb)->h_dest, dev->addr_len);
memcpy(eth_hdr(skb)->h_dest, n->ha, dev->addr_len);
If the incoming skb is cloned (for example by packet sockets, tcpdump, or
dev_queue_xmit), modifying the Ethernet header without uncloning can corrupt
the packet header for other readers holding a reference to the cloned skb.
Ensure the skb header is writable and unshared by calling skb_cow_head(skb, 0)
prior to updating the Ethernet header. If skb_cow_head() fails, abort short-circuiting
and return false to allow standard packet processing fallback.
Fixes: e4f67addf158 ("add DOVE extensions for VXLAN")
Cc: stable@vger.kernel.org
Signed-off-by: Eric Dumazet <edumazet@google.com>
---
drivers/net/vxlan/vxlan_core.c | 4 ++++
1 file changed, 4 insertions(+)
diff --git a/drivers/net/vxlan/vxlan_core.c b/drivers/net/vxlan/vxlan_core.c
index 9060a1259ac283d4db4b7a854ce74203496e9313..fb4a706cd5786d1937b1922acced31ffdb187c2f 100644
--- a/drivers/net/vxlan/vxlan_core.c
+++ b/drivers/net/vxlan/vxlan_core.c
@@ -2163,6 +2163,10 @@ static bool route_shortcircuit(struct net_device *dev, struct sk_buff *skb)
diff = !ether_addr_equal(eth_hdr(skb)->h_dest, n->ha);
if (diff) {
+ if (skb_cow_head(skb, 0)) {
+ neigh_release(n);
+ return false;
+ }
memcpy(eth_hdr(skb)->h_source, eth_hdr(skb)->h_dest,
dev->addr_len);
memcpy(eth_hdr(skb)->h_dest, n->ha, dev->addr_len);
--
2.55.0.229.g6434b31f56-goog
^ permalink raw reply related [flat|nested] 10+ messages in thread* [PATCH net 3/5] vxlan: use neigh_ha_snapshot() in route_shortcircuit()
[not found] <20260723144249.759100-1-edumazet@google.com>
2026-07-23 14:42 ` [PATCH net 1/5] vxlan: re-fetch eth header after route_shortcircuit() Eric Dumazet
2026-07-23 14:42 ` [PATCH net 2/5] vxlan: unclone skb head before modifying eth header in route_shortcircuit() Eric Dumazet
@ 2026-07-23 14:42 ` Eric Dumazet
2026-07-23 16:41 ` Vadim Fedorenko
2026-07-23 14:42 ` [PATCH net 4/5] vxlan: use pskb_network_may_pull() " Eric Dumazet
2026-07-23 14:42 ` [PATCH net 5/5] vxlan: use pskb_network_may_pull() for transmit path header pulls Eric Dumazet
4 siblings, 1 reply; 10+ messages in thread
From: Eric Dumazet @ 2026-07-23 14:42 UTC (permalink / raw)
To: David S . Miller, Jakub Kicinski, Paolo Abeni
Cc: Simon Horman, Ido Schimmel, Andrew Lunn, netdev, eric.dumazet,
Eric Dumazet, stable
The neighbour hardware address n->ha can be updated asynchronously by the
neighbour subsystem, protected by n->ha_lock seqlock. Reading n->ha without
holding the seqlock loop can lead to torn reads or reading a partially updated
MAC address.
Use neigh_ha_snapshot() in route_shortcircuit() to safely copy n->ha under
read_seqbegin()/read_seqretry() lock protection before using it.
Note that arp_reduce() and neigh_reduce() seem to have the same issue
left for future patches.
Fixes: e4f67addf158 ("add DOVE extensions for VXLAN")
Cc: stable@vger.kernel.org
Signed-off-by: Eric Dumazet <edumazet@google.com>
---
drivers/net/vxlan/vxlan_core.c | 6 ++++--
1 file changed, 4 insertions(+), 2 deletions(-)
diff --git a/drivers/net/vxlan/vxlan_core.c b/drivers/net/vxlan/vxlan_core.c
index fb4a706cd5786d1937b1922acced31ffdb187c2f..10dd19eec09e266197ee51330a652f4e76c9643a 100644
--- a/drivers/net/vxlan/vxlan_core.c
+++ b/drivers/net/vxlan/vxlan_core.c
@@ -2159,9 +2159,11 @@ static bool route_shortcircuit(struct net_device *dev, struct sk_buff *skb)
}
if (n) {
+ u8 haddr[ETH_ALEN];
bool diff;
- diff = !ether_addr_equal(eth_hdr(skb)->h_dest, n->ha);
+ neigh_ha_snapshot(haddr, n, dev);
+ diff = !ether_addr_equal_unaligned(eth_hdr(skb)->h_dest, haddr);
if (diff) {
if (skb_cow_head(skb, 0)) {
neigh_release(n);
@@ -2169,7 +2171,7 @@ static bool route_shortcircuit(struct net_device *dev, struct sk_buff *skb)
}
memcpy(eth_hdr(skb)->h_source, eth_hdr(skb)->h_dest,
dev->addr_len);
- memcpy(eth_hdr(skb)->h_dest, n->ha, dev->addr_len);
+ memcpy(eth_hdr(skb)->h_dest, haddr, dev->addr_len);
}
neigh_release(n);
return diff;
--
2.55.0.229.g6434b31f56-goog
^ permalink raw reply related [flat|nested] 10+ messages in thread* Re: [PATCH net 3/5] vxlan: use neigh_ha_snapshot() in route_shortcircuit()
2026-07-23 14:42 ` [PATCH net 3/5] vxlan: use neigh_ha_snapshot() " Eric Dumazet
@ 2026-07-23 16:41 ` Vadim Fedorenko
0 siblings, 0 replies; 10+ messages in thread
From: Vadim Fedorenko @ 2026-07-23 16:41 UTC (permalink / raw)
To: Eric Dumazet, David S . Miller, Jakub Kicinski, Paolo Abeni
Cc: Simon Horman, Ido Schimmel, Andrew Lunn, netdev, eric.dumazet,
stable
On 23/07/2026 15:42, Eric Dumazet wrote:
> The neighbour hardware address n->ha can be updated asynchronously by the
> neighbour subsystem, protected by n->ha_lock seqlock. Reading n->ha without
> holding the seqlock loop can lead to torn reads or reading a partially updated
> MAC address.
>
> Use neigh_ha_snapshot() in route_shortcircuit() to safely copy n->ha under
> read_seqbegin()/read_seqretry() lock protection before using it.
>
> Note that arp_reduce() and neigh_reduce() seem to have the same issue
> left for future patches.
>
> Fixes: e4f67addf158 ("add DOVE extensions for VXLAN")
> Cc: stable@vger.kernel.org
> Signed-off-by: Eric Dumazet <edumazet@google.com>
> ---
> drivers/net/vxlan/vxlan_core.c | 6 ++++--
> 1 file changed, 4 insertions(+), 2 deletions(-)
>
> diff --git a/drivers/net/vxlan/vxlan_core.c b/drivers/net/vxlan/vxlan_core.c
> index fb4a706cd5786d1937b1922acced31ffdb187c2f..10dd19eec09e266197ee51330a652f4e76c9643a 100644
> --- a/drivers/net/vxlan/vxlan_core.c
> +++ b/drivers/net/vxlan/vxlan_core.c
> @@ -2159,9 +2159,11 @@ static bool route_shortcircuit(struct net_device *dev, struct sk_buff *skb)
> }
>
> if (n) {
> + u8 haddr[ETH_ALEN];
> bool diff;
>
> - diff = !ether_addr_equal(eth_hdr(skb)->h_dest, n->ha);
> + neigh_ha_snapshot(haddr, n, dev);
> + diff = !ether_addr_equal_unaligned(eth_hdr(skb)->h_dest, haddr);
> if (diff) {
> if (skb_cow_head(skb, 0)) {
> neigh_release(n);
> @@ -2169,7 +2171,7 @@ static bool route_shortcircuit(struct net_device *dev, struct sk_buff *skb)
> }
> memcpy(eth_hdr(skb)->h_source, eth_hdr(skb)->h_dest,
> dev->addr_len);
> - memcpy(eth_hdr(skb)->h_dest, n->ha, dev->addr_len);
> + memcpy(eth_hdr(skb)->h_dest, haddr, dev->addr_len);
> }
> neigh_release(n);
> return diff;
Reviewed-by: Vadim Fedorenko <vadim.fedorenko@linux.dev>
^ permalink raw reply [flat|nested] 10+ messages in thread
* [PATCH net 4/5] vxlan: use pskb_network_may_pull() in route_shortcircuit()
[not found] <20260723144249.759100-1-edumazet@google.com>
` (2 preceding siblings ...)
2026-07-23 14:42 ` [PATCH net 3/5] vxlan: use neigh_ha_snapshot() " Eric Dumazet
@ 2026-07-23 14:42 ` Eric Dumazet
2026-07-23 16:42 ` Vadim Fedorenko
2026-07-23 14:42 ` [PATCH net 5/5] vxlan: use pskb_network_may_pull() for transmit path header pulls Eric Dumazet
4 siblings, 1 reply; 10+ messages in thread
From: Eric Dumazet @ 2026-07-23 14:42 UTC (permalink / raw)
To: David S . Miller, Jakub Kicinski, Paolo Abeni
Cc: Simon Horman, Ido Schimmel, Andrew Lunn, netdev, eric.dumazet,
Eric Dumazet, stable
route_shortcircuit() currently calls pskb_may_pull(skb, sizeof(struct iphdr))
(or ipv6hdr), which checks if bytes are available starting from skb->data.
However, in vxlan_xmit(), skb->data points to the MAC header, so
skb_network_offset(skb) is ETH_HLEN (14 bytes). Using pskb_may_pull(skb, 20)
only checks 20 bytes from skb->data (which is 14 bytes MAC header + 6 bytes of
IP header), leaving the rest of the IP header potentially un-pulled in non-linear
frags. Subsequent dereferences of ip_hdr(skb)->daddr can read beyond the pulled
linear buffer length.
Fix this by using pskb_network_may_pull(), which adds skb_network_offset(skb) to
the length check to ensure the full network header is present in the linear buffer.
Fixes: e4f67addf158 ("add DOVE extensions for VXLAN")
Cc: stable@vger.kernel.org
Signed-off-by: Eric Dumazet <edumazet@google.com>
---
drivers/net/vxlan/vxlan_core.c | 4 ++--
1 file changed, 2 insertions(+), 2 deletions(-)
diff --git a/drivers/net/vxlan/vxlan_core.c b/drivers/net/vxlan/vxlan_core.c
index 10dd19eec09e266197ee51330a652f4e76c9643a..9ccbebda860480f8378918ff360deee1c46f3f7d 100644
--- a/drivers/net/vxlan/vxlan_core.c
+++ b/drivers/net/vxlan/vxlan_core.c
@@ -2111,7 +2111,7 @@ static bool route_shortcircuit(struct net_device *dev, struct sk_buff *skb)
{
struct iphdr *pip;
- if (!pskb_may_pull(skb, sizeof(struct iphdr)))
+ if (!pskb_network_may_pull(skb, sizeof(struct iphdr)))
return false;
pip = ip_hdr(skb);
n = neigh_lookup(&arp_tbl, &pip->daddr, dev);
@@ -2137,7 +2137,7 @@ static bool route_shortcircuit(struct net_device *dev, struct sk_buff *skb)
*/
if (!ipv6_mod_enabled())
return false;
- if (!pskb_may_pull(skb, sizeof(struct ipv6hdr)))
+ if (!pskb_network_may_pull(skb, sizeof(struct ipv6hdr)))
return false;
pip6 = ipv6_hdr(skb);
n = neigh_lookup(&nd_tbl, &pip6->daddr, dev);
--
2.55.0.229.g6434b31f56-goog
^ permalink raw reply related [flat|nested] 10+ messages in thread* Re: [PATCH net 4/5] vxlan: use pskb_network_may_pull() in route_shortcircuit()
2026-07-23 14:42 ` [PATCH net 4/5] vxlan: use pskb_network_may_pull() " Eric Dumazet
@ 2026-07-23 16:42 ` Vadim Fedorenko
0 siblings, 0 replies; 10+ messages in thread
From: Vadim Fedorenko @ 2026-07-23 16:42 UTC (permalink / raw)
To: Eric Dumazet, David S . Miller, Jakub Kicinski, Paolo Abeni
Cc: Simon Horman, Ido Schimmel, Andrew Lunn, netdev, eric.dumazet,
stable
On 23/07/2026 15:42, Eric Dumazet wrote:
> route_shortcircuit() currently calls pskb_may_pull(skb, sizeof(struct iphdr))
> (or ipv6hdr), which checks if bytes are available starting from skb->data.
>
> However, in vxlan_xmit(), skb->data points to the MAC header, so
> skb_network_offset(skb) is ETH_HLEN (14 bytes). Using pskb_may_pull(skb, 20)
> only checks 20 bytes from skb->data (which is 14 bytes MAC header + 6 bytes of
> IP header), leaving the rest of the IP header potentially un-pulled in non-linear
> frags. Subsequent dereferences of ip_hdr(skb)->daddr can read beyond the pulled
> linear buffer length.
>
> Fix this by using pskb_network_may_pull(), which adds skb_network_offset(skb) to
> the length check to ensure the full network header is present in the linear buffer.
>
> Fixes: e4f67addf158 ("add DOVE extensions for VXLAN")
> Cc: stable@vger.kernel.org
> Signed-off-by: Eric Dumazet <edumazet@google.com>
> ---
> drivers/net/vxlan/vxlan_core.c | 4 ++--
> 1 file changed, 2 insertions(+), 2 deletions(-)
>
> diff --git a/drivers/net/vxlan/vxlan_core.c b/drivers/net/vxlan/vxlan_core.c
> index 10dd19eec09e266197ee51330a652f4e76c9643a..9ccbebda860480f8378918ff360deee1c46f3f7d 100644
> --- a/drivers/net/vxlan/vxlan_core.c
> +++ b/drivers/net/vxlan/vxlan_core.c
> @@ -2111,7 +2111,7 @@ static bool route_shortcircuit(struct net_device *dev, struct sk_buff *skb)
> {
> struct iphdr *pip;
>
> - if (!pskb_may_pull(skb, sizeof(struct iphdr)))
> + if (!pskb_network_may_pull(skb, sizeof(struct iphdr)))
> return false;
> pip = ip_hdr(skb);
> n = neigh_lookup(&arp_tbl, &pip->daddr, dev);
> @@ -2137,7 +2137,7 @@ static bool route_shortcircuit(struct net_device *dev, struct sk_buff *skb)
> */
> if (!ipv6_mod_enabled())
> return false;
> - if (!pskb_may_pull(skb, sizeof(struct ipv6hdr)))
> + if (!pskb_network_may_pull(skb, sizeof(struct ipv6hdr)))
> return false;
> pip6 = ipv6_hdr(skb);
> n = neigh_lookup(&nd_tbl, &pip6->daddr, dev);
Reviewed-by: Vadim Fedorenko <vadim.fedorenko@linux.dev>
^ permalink raw reply [flat|nested] 10+ messages in thread
* [PATCH net 5/5] vxlan: use pskb_network_may_pull() for transmit path header pulls
[not found] <20260723144249.759100-1-edumazet@google.com>
` (3 preceding siblings ...)
2026-07-23 14:42 ` [PATCH net 4/5] vxlan: use pskb_network_may_pull() " Eric Dumazet
@ 2026-07-23 14:42 ` Eric Dumazet
2026-07-23 16:43 ` Vadim Fedorenko
2026-07-26 10:34 ` Ido Schimmel
4 siblings, 2 replies; 10+ messages in thread
From: Eric Dumazet @ 2026-07-23 14:42 UTC (permalink / raw)
To: David S . Miller, Jakub Kicinski, Paolo Abeni
Cc: Simon Horman, Ido Schimmel, Andrew Lunn, netdev, eric.dumazet,
Eric Dumazet, stable
In vxlan_xmit(), arp_reduce(), and vxlan_mdb_entry_skb_get(), pskb_may_pull() was
being called to verify the availability of network layer headers (ARP, IPv6/ND,
IP/IPv6 MDB keys).
However, during transmit skb->data points to the MAC header, so skb_network_offset(skb)
is ETH_HLEN (14 bytes). Using pskb_may_pull(skb, len) only checks len bytes from skb->data
rather than skb_network_offset(skb) + len, which can leave part of the network header
in non-linear frags.
Replace these remaining pskb_may_pull() calls with pskb_network_may_pull() to properly
account for the MAC header offset.
Fixes: 465016142711 ("vxlan: Add ARP reduction support")
Fixes: 9e061a50a116 ("vxlan: Add IPv6 Neighbor Discovery reduction support")
Fixes: 4e94f09d84bf ("vxlan: add MDB support")
Signed-off-by: Eric Dumazet <edumazet@google.com>
Cc: stable@vger.kernel.org
---
drivers/net/vxlan/vxlan_core.c | 6 +++---
drivers/net/vxlan/vxlan_mdb.c | 4 ++--
2 files changed, 5 insertions(+), 5 deletions(-)
diff --git a/drivers/net/vxlan/vxlan_core.c b/drivers/net/vxlan/vxlan_core.c
index 9ccbebda860480f8378918ff360deee1c46f3f7d..eff17987c5b531ecb1e2943b6274d20c1827d299 100644
--- a/drivers/net/vxlan/vxlan_core.c
+++ b/drivers/net/vxlan/vxlan_core.c
@@ -1850,7 +1850,7 @@ static int arp_reduce(struct net_device *dev, struct sk_buff *skb, __be32 vni)
if (dev->flags & IFF_NOARP)
goto out;
- if (!pskb_may_pull(skb, arp_hdr_len(dev))) {
+ if (!pskb_network_may_pull(skb, arp_hdr_len(dev))) {
dev_dstats_tx_dropped(dev);
vxlan_vnifilter_count(vxlan, vni, NULL,
VXLAN_VNI_STATS_TX_DROPS, 0);
@@ -2763,8 +2763,8 @@ static netdev_tx_t vxlan_xmit(struct sk_buff *skb, struct net_device *dev)
return arp_reduce(dev, skb, vni);
#if IS_ENABLED(CONFIG_IPV6)
else if (ntohs(eth->h_proto) == ETH_P_IPV6 &&
- pskb_may_pull(skb, sizeof(struct ipv6hdr) +
- sizeof(struct nd_msg)) &&
+ pskb_network_may_pull(skb, sizeof(struct ipv6hdr) +
+ sizeof(struct nd_msg)) &&
ipv6_hdr(skb)->nexthdr == IPPROTO_ICMPV6) {
struct nd_msg *m = (struct nd_msg *)(ipv6_hdr(skb) + 1);
diff --git a/drivers/net/vxlan/vxlan_mdb.c b/drivers/net/vxlan/vxlan_mdb.c
index af7a0d7f95a57a17486a8ecc277b7bb9d921a061..9a9038ae90c18c5f0e4362b2b254b0c48dfdad0e 100644
--- a/drivers/net/vxlan/vxlan_mdb.c
+++ b/drivers/net/vxlan/vxlan_mdb.c
@@ -1631,7 +1631,7 @@ struct vxlan_mdb_entry *vxlan_mdb_entry_skb_get(struct vxlan_dev *vxlan,
switch (skb->protocol) {
case htons(ETH_P_IP):
- if (!pskb_may_pull(skb, sizeof(struct iphdr)))
+ if (!pskb_network_may_pull(skb, sizeof(struct iphdr)))
return NULL;
group.dst.sa.sa_family = AF_INET;
group.dst.sin.sin_addr.s_addr = ip_hdr(skb)->daddr;
@@ -1640,7 +1640,7 @@ struct vxlan_mdb_entry *vxlan_mdb_entry_skb_get(struct vxlan_dev *vxlan,
break;
#if IS_ENABLED(CONFIG_IPV6)
case htons(ETH_P_IPV6):
- if (!pskb_may_pull(skb, sizeof(struct ipv6hdr)))
+ if (!pskb_network_may_pull(skb, sizeof(struct ipv6hdr)))
return NULL;
group.dst.sa.sa_family = AF_INET6;
group.dst.sin6.sin6_addr = ipv6_hdr(skb)->daddr;
--
2.55.0.229.g6434b31f56-goog
^ permalink raw reply related [flat|nested] 10+ messages in thread* Re: [PATCH net 5/5] vxlan: use pskb_network_may_pull() for transmit path header pulls
2026-07-23 14:42 ` [PATCH net 5/5] vxlan: use pskb_network_may_pull() for transmit path header pulls Eric Dumazet
@ 2026-07-23 16:43 ` Vadim Fedorenko
2026-07-26 10:34 ` Ido Schimmel
1 sibling, 0 replies; 10+ messages in thread
From: Vadim Fedorenko @ 2026-07-23 16:43 UTC (permalink / raw)
To: Eric Dumazet, David S . Miller, Jakub Kicinski, Paolo Abeni
Cc: Simon Horman, Ido Schimmel, Andrew Lunn, netdev, eric.dumazet,
stable
On 23/07/2026 15:42, Eric Dumazet wrote:
> In vxlan_xmit(), arp_reduce(), and vxlan_mdb_entry_skb_get(), pskb_may_pull() was
> being called to verify the availability of network layer headers (ARP, IPv6/ND,
> IP/IPv6 MDB keys).
>
> However, during transmit skb->data points to the MAC header, so skb_network_offset(skb)
> is ETH_HLEN (14 bytes). Using pskb_may_pull(skb, len) only checks len bytes from skb->data
> rather than skb_network_offset(skb) + len, which can leave part of the network header
> in non-linear frags.
>
> Replace these remaining pskb_may_pull() calls with pskb_network_may_pull() to properly
> account for the MAC header offset.
>
> Fixes: 465016142711 ("vxlan: Add ARP reduction support")
> Fixes: 9e061a50a116 ("vxlan: Add IPv6 Neighbor Discovery reduction support")
> Fixes: 4e94f09d84bf ("vxlan: add MDB support")
> Signed-off-by: Eric Dumazet <edumazet@google.com>
> Cc: stable@vger.kernel.org
> ---
> drivers/net/vxlan/vxlan_core.c | 6 +++---
> drivers/net/vxlan/vxlan_mdb.c | 4 ++--
> 2 files changed, 5 insertions(+), 5 deletions(-)
>
> diff --git a/drivers/net/vxlan/vxlan_core.c b/drivers/net/vxlan/vxlan_core.c
> index 9ccbebda860480f8378918ff360deee1c46f3f7d..eff17987c5b531ecb1e2943b6274d20c1827d299 100644
> --- a/drivers/net/vxlan/vxlan_core.c
> +++ b/drivers/net/vxlan/vxlan_core.c
> @@ -1850,7 +1850,7 @@ static int arp_reduce(struct net_device *dev, struct sk_buff *skb, __be32 vni)
> if (dev->flags & IFF_NOARP)
> goto out;
>
> - if (!pskb_may_pull(skb, arp_hdr_len(dev))) {
> + if (!pskb_network_may_pull(skb, arp_hdr_len(dev))) {
> dev_dstats_tx_dropped(dev);
> vxlan_vnifilter_count(vxlan, vni, NULL,
> VXLAN_VNI_STATS_TX_DROPS, 0);
> @@ -2763,8 +2763,8 @@ static netdev_tx_t vxlan_xmit(struct sk_buff *skb, struct net_device *dev)
> return arp_reduce(dev, skb, vni);
> #if IS_ENABLED(CONFIG_IPV6)
> else if (ntohs(eth->h_proto) == ETH_P_IPV6 &&
> - pskb_may_pull(skb, sizeof(struct ipv6hdr) +
> - sizeof(struct nd_msg)) &&
> + pskb_network_may_pull(skb, sizeof(struct ipv6hdr) +
> + sizeof(struct nd_msg)) &&
> ipv6_hdr(skb)->nexthdr == IPPROTO_ICMPV6) {
> struct nd_msg *m = (struct nd_msg *)(ipv6_hdr(skb) + 1);
>
> diff --git a/drivers/net/vxlan/vxlan_mdb.c b/drivers/net/vxlan/vxlan_mdb.c
> index af7a0d7f95a57a17486a8ecc277b7bb9d921a061..9a9038ae90c18c5f0e4362b2b254b0c48dfdad0e 100644
> --- a/drivers/net/vxlan/vxlan_mdb.c
> +++ b/drivers/net/vxlan/vxlan_mdb.c
> @@ -1631,7 +1631,7 @@ struct vxlan_mdb_entry *vxlan_mdb_entry_skb_get(struct vxlan_dev *vxlan,
>
> switch (skb->protocol) {
> case htons(ETH_P_IP):
> - if (!pskb_may_pull(skb, sizeof(struct iphdr)))
> + if (!pskb_network_may_pull(skb, sizeof(struct iphdr)))
> return NULL;
> group.dst.sa.sa_family = AF_INET;
> group.dst.sin.sin_addr.s_addr = ip_hdr(skb)->daddr;
> @@ -1640,7 +1640,7 @@ struct vxlan_mdb_entry *vxlan_mdb_entry_skb_get(struct vxlan_dev *vxlan,
> break;
> #if IS_ENABLED(CONFIG_IPV6)
> case htons(ETH_P_IPV6):
> - if (!pskb_may_pull(skb, sizeof(struct ipv6hdr)))
> + if (!pskb_network_may_pull(skb, sizeof(struct ipv6hdr)))
> return NULL;
> group.dst.sa.sa_family = AF_INET6;
> group.dst.sin6.sin6_addr = ipv6_hdr(skb)->daddr;
Reviewed-by: Vadim Fedorenko <vadim.fedorenko@linux.dev>
^ permalink raw reply [flat|nested] 10+ messages in thread* Re: [PATCH net 5/5] vxlan: use pskb_network_may_pull() for transmit path header pulls
2026-07-23 14:42 ` [PATCH net 5/5] vxlan: use pskb_network_may_pull() for transmit path header pulls Eric Dumazet
2026-07-23 16:43 ` Vadim Fedorenko
@ 2026-07-26 10:34 ` Ido Schimmel
1 sibling, 0 replies; 10+ messages in thread
From: Ido Schimmel @ 2026-07-26 10:34 UTC (permalink / raw)
To: Eric Dumazet
Cc: David S . Miller, Jakub Kicinski, Paolo Abeni, Simon Horman,
Andrew Lunn, netdev, eric.dumazet, stable
On Thu, Jul 23, 2026 at 02:42:49PM +0000, Eric Dumazet wrote:
> In vxlan_xmit(), arp_reduce(), and vxlan_mdb_entry_skb_get(), pskb_may_pull() was
> being called to verify the availability of network layer headers (ARP, IPv6/ND,
> IP/IPv6 MDB keys).
>
> However, during transmit skb->data points to the MAC header, so skb_network_offset(skb)
> is ETH_HLEN (14 bytes). Using pskb_may_pull(skb, len) only checks len bytes from skb->data
> rather than skb_network_offset(skb) + len, which can leave part of the network header
> in non-linear frags.
>
> Replace these remaining pskb_may_pull() calls with pskb_network_may_pull() to properly
> account for the MAC header offset.
>
> Fixes: 465016142711 ("vxlan: Add ARP reduction support")
> Fixes: 9e061a50a116 ("vxlan: Add IPv6 Neighbor Discovery reduction support")
> Fixes: 4e94f09d84bf ("vxlan: add MDB support")
I think you meant:
Fixes: e4f67addf158 ("add DOVE extensions for VXLAN")
Fixes: f564f45c4518 ("vxlan: add ipv6 proxy support")
Fixes: 0f83e69f44bf ("vxlan: Add MDB data path support")
> Signed-off-by: Eric Dumazet <edumazet@google.com>
> Cc: stable@vger.kernel.org
Reviewed-by: Ido Schimmel <idosch@nvidia.com>
Thanks!
^ permalink raw reply [flat|nested] 10+ messages in thread