[PATCH net 0/2] Don't assume linear buffers in error handlers for VXLAN and GENEVE

[PATCH net 0/2] Don't assume linear buffers in error handlers for VXLAN and GENEVE

[Stefano Brivio]

Guillaume noticed the same issue fixed by commit 26fc181e6cac ("fou, fou6:
do not assume linear skbs") for fou and fou6 is also present in VXLAN and
GENEVE error handlers: we can't assume linear buffers there, we need to
use pskb_may_pull() instead.

Stefano Brivio (2):
  vxlan: Don't assume linear buffers in error handler
  geneve: Don't assume linear buffers in error handler

 drivers/net/geneve.c | 2 +-
 drivers/net/vxlan.c  | 2 +-
 2 files changed, 2 insertions(+), 2 deletions(-)

-- 
2.20.1

[PATCH net 1/2] vxlan: Don't assume linear buffers in error handler

[Stefano Brivio]

In commit c3a43b9fec8a ("vxlan: ICMP error lookup handler") I wrongly
assumed buffers from icmp_socket_deliver() would be linear. This is not
the case: icmp_socket_deliver() only guarantees we have 8 bytes of linear
data.

Eric fixed this same issue for fou and fou6 in commits 26fc181e6cac
("fou, fou6: do not assume linear skbs") and 5355ed6388e2 ("fou, fou6:
avoid uninit-value in gue_err() and gue6_err()").

Use pskb_may_pull() instead of checking skb->len, and take into account
the fact we later access the VXLAN header with udp_hdr(), so we also
need to sum skb_transport_header() here.

Reported-by: Guillaume Nault <gnault@redhat.com>
Fixes: c3a43b9fec8a ("vxlan: ICMP error lookup handler")
Signed-off-by: Stefano Brivio <sbrivio@redhat.com>
---
 drivers/net/vxlan.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/drivers/net/vxlan.c b/drivers/net/vxlan.c
index 5994d5415a03..4c9bc29fe3d5 100644
--- a/drivers/net/vxlan.c
+++ b/drivers/net/vxlan.c
@@ -1766,7 +1766,7 @@ static int vxlan_err_lookup(struct sock *sk, struct sk_buff *skb)
 	struct vxlanhdr *hdr;
 	__be32 vni;
 
-	if (skb->len < VXLAN_HLEN)
+	if (!pskb_may_pull(skb, skb_transport_offset(skb) + VXLAN_HLEN))
 		return -EINVAL;
 
 	hdr = vxlan_hdr(skb);
-- 
2.20.1

[PATCH net 2/2] geneve: Don't assume linear buffers in error handler

[Stefano Brivio]

In commit a07966447f39 ("geneve: ICMP error lookup handler") I wrongly
assumed buffers from icmp_socket_deliver() would be linear. This is not
the case: icmp_socket_deliver() only guarantees we have 8 bytes of linear
data.

Eric fixed this same issue for fou and fou6 in commits 26fc181e6cac
("fou, fou6: do not assume linear skbs") and 5355ed6388e2 ("fou, fou6:
avoid uninit-value in gue_err() and gue6_err()").

Use pskb_may_pull() instead of checking skb->len, and take into account
the fact we later access the GENEVE header with udp_hdr(), so we also
need to sum skb_transport_header() here.

Reported-by: Guillaume Nault <gnault@redhat.com>
Fixes: a07966447f39 ("geneve: ICMP error lookup handler")
Signed-off-by: Stefano Brivio <sbrivio@redhat.com>
---
 drivers/net/geneve.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/drivers/net/geneve.c b/drivers/net/geneve.c
index 98d1a45c0606..25770122c219 100644
--- a/drivers/net/geneve.c
+++ b/drivers/net/geneve.c
@@ -395,7 +395,7 @@ static int geneve_udp_encap_err_lookup(struct sock *sk, struct sk_buff *skb)
 	u8 zero_vni[3] = { 0 };
 	u8 *vni = zero_vni;
 
-	if (skb->len < GENEVE_BASE_HLEN)
+	if (!pskb_may_pull(skb, skb_transport_offset(skb) + GENEVE_BASE_HLEN))
 		return -EINVAL;
 
 	geneveh = geneve_hdr(skb);
-- 
2.20.1

Re: [PATCH net 0/2] Don't assume linear buffers in error handlers for VXLAN and GENEVE

[Guillaume Nault]

On Tue, Jun 11, 2019 at 12:27:04AM +0200, Stefano Brivio wrote:
> Guillaume noticed the same issue fixed by commit 26fc181e6cac ("fou, fou6:
> do not assume linear skbs") for fou and fou6 is also present in VXLAN and
> GENEVE error handlers: we can't assume linear buffers there, we need to
> use pskb_may_pull() instead.
> 
Acked-by: Guillaume Nault <gnault@redhat.com>

Re: [PATCH net 0/2] Don't assume linear buffers in error handlers for VXLAN and GENEVE

[David Miller]

From: Stefano Brivio <sbrivio@redhat.com>
Date: Tue, 11 Jun 2019 00:27:04 +0200

> Guillaume noticed the same issue fixed by commit 26fc181e6cac ("fou, fou6:
> do not assume linear skbs") for fou and fou6 is also present in VXLAN and
> GENEVE error handlers: we can't assume linear buffers there, we need to
> use pskb_may_pull() instead.

Series applied and queued up for -stable, thanks for fixing this.