[PATCH 4.14 45/71] gso: validate gso_type in GSO handlers

[Greg Kroah-Hartman]

4.14-stable review patch.  If anyone has any objections, please let me know.

------------------

From: Willem de Bruijn <will...@google.com>


[ 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/<001a1137452496ffc305617e5...@google.com>
Reported-by: syzbot+fee64147a25aecd48...@syzkaller.appspotmail.com
Signed-off-by: Willem de Bruijn <will...@google.com>
Acked-by: Jason Wang <jasow...@redhat.com>
Reviewed-by: Marcelo Ricardo Leitner <marcelo.leit...@gmail.com>
Signed-off-by: David S. Miller <da...@davemloft.net>
Signed-off-by: Greg Kroah-Hartman <gre...@linuxfoundation.org>
---
 net/ipv4/esp4_offload.c  |    3 +++
 net/ipv4/tcp_offload.c   |    3 +++
 net/ipv4/udp_offload.c   |    3 +++
 net/ipv6/esp6_offload.c  |    3 +++
 net/ipv6/tcpv6_offload.c |    3 +++
 net/ipv6/udp_offload.c   |    3 +++
 net/sctp/offload.c       |    3 +++
 7 files changed, 21 insertions(+)

--- a/net/ipv4/esp4_offload.c
+++ b/net/ipv4/esp4_offload.c
@@ -121,6 +121,9 @@ static struct sk_buff *esp4_gso_segment(
        if (!xo)
                goto out;
 
+       if (!(skb_shinfo(skb)->gso_type & SKB_GSO_ESP))
+               goto out;
+
        seq = xo->seq.low;
 
        x = skb->sp->xvec[skb->sp->len - 1];
--- 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
@@ -203,6 +203,9 @@ 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/esp6_offload.c
+++ b/net/ipv6/esp6_offload.c
@@ -148,6 +148,9 @@ static struct sk_buff *esp6_gso_segment(
        if (!xo)
                goto out;
 
+       if (!(skb_shinfo(skb)->gso_type & SKB_GSO_ESP))
+               goto out;
+
        seq = xo->seq.low;
 
        x = skb->sp->xvec[skb->sp->len - 1];
--- 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
@@ -42,6 +42,9 @@ 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
@@ -45,6 +45,9 @@ 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;