4.9-stable review patch. If anyone has any objections, please let me know.
------------------
From: Willem de Bruijn <willemb@xxxxxxxxxx>
[ Upstream commit 121d57af308d0cf943f08f4738d24d3966c38cd9 ]
Validate gso_type during segmentation as SKB_GSO_DODGY sources
may pass packets where the gso_type does not match the contents.
Syzkaller was able to enter the SCTP gso handler with a packet of
gso_type SKB_GSO_TCPV4.
On entry of transport layer gso handlers, verify that the gso_type
matches the transport protocol.
Fixes: 90017accff61 ("sctp: Add GSO support")
Link: http://lkml.kernel.org/r/<001a1137452496ffc305617e5fe0@xxxxxxxxxx>
Reported-by: syzbot+fee64147a25aecd48055@xxxxxxxxxxxxxxxxxxxxxxxxx
Signed-off-by: Willem de Bruijn <willemb@xxxxxxxxxx>
Acked-by: Jason Wang <jasowang@xxxxxxxxxx>
Reviewed-by: Marcelo Ricardo Leitner <marcelo.leitner@xxxxxxxxx>
Signed-off-by: David S. Miller <davem@xxxxxxxxxxxxx>
Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx>
---
net/ipv4/tcp_offload.c | 3 +++
net/ipv4/udp_offload.c | 3 +++
net/ipv6/tcpv6_offload.c | 3 +++
net/ipv6/udp_offload.c | 3 +++
net/sctp/offload.c | 3 +++
5 files changed, 15 insertions(+)
--- a/net/ipv4/tcp_offload.c
+++ b/net/ipv4/tcp_offload.c
@@ -32,6 +32,9 @@ static void tcp_gso_tstamp(struct sk_buf
static struct sk_buff *tcp4_gso_segment(struct sk_buff *skb,
netdev_features_t features)
{
+ if (!(skb_shinfo(skb)->gso_type & SKB_GSO_TCPV4))
+ return ERR_PTR(-EINVAL);
+
if (!pskb_may_pull(skb, sizeof(struct tcphdr)))
return ERR_PTR(-EINVAL);
--- a/net/ipv4/udp_offload.c
+++ b/net/ipv4/udp_offload.c
@@ -205,6 +205,9 @@ static struct sk_buff *udp4_ufo_fragment
goto out;
}
+ if (!(skb_shinfo(skb)->gso_type & SKB_GSO_UDP))
+ goto out;
+
if (!pskb_may_pull(skb, sizeof(struct udphdr)))
goto out;
--- a/net/ipv6/tcpv6_offload.c
+++ b/net/ipv6/tcpv6_offload.c
@@ -46,6 +46,9 @@ static struct sk_buff *tcp6_gso_segment(
{
struct tcphdr *th;
+ if (!(skb_shinfo(skb)->gso_type & SKB_GSO_TCPV6))
+ return ERR_PTR(-EINVAL);
+
if (!pskb_may_pull(skb, sizeof(*th)))
return ERR_PTR(-EINVAL);
--- a/net/ipv6/udp_offload.c
+++ b/net/ipv6/udp_offload.c
@@ -55,6 +55,9 @@ static struct sk_buff *udp6_ufo_fragment
const struct ipv6hdr *ipv6h;
struct udphdr *uh;
+ if (!(skb_shinfo(skb)->gso_type & SKB_GSO_UDP))
+ goto out;
+
if (!pskb_may_pull(skb, sizeof(struct udphdr)))
goto out;
--- a/net/sctp/offload.c
+++ b/net/sctp/offload.c
@@ -44,6 +44,9 @@ static struct sk_buff *sctp_gso_segment(
struct sk_buff *segs = ERR_PTR(-EINVAL);
struct sctphdr *sh;
+ if (!(skb_shinfo(skb)->gso_type & SKB_GSO_SCTP))
+ goto out;
+
sh = sctp_hdr(skb);
if (!pskb_may_pull(skb, sizeof(*sh)))
goto out;