gso: validate gso_type in GSO handlers

[ 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@google.com>
Reported-by: syzbot+fee64147a25aecd48055@syzkaller.appspotmail.com
Signed-off-by: Willem de Bruijn <willemb@google.com>
Acked-by: Jason Wang <jasowang@redhat.com>
Reviewed-by: Marcelo Ricardo Leitner <marcelo.leitner@gmail.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

diff --git a/net/ipv4/tcp_offload.c b/net/ipv4/tcp_offload.c
index bc68da3..366b1be 100644 (file)
--- a/net/ipv4/tcp_offload.c
+++ b/net/ipv4/tcp_offload.c
@@ -32,6 +32,9 @@ static void tcp_gso_tstamp(struct sk_buff *skb, unsigned int ts_seq,
 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);
 

diff --git a/net/ipv4/udp_offload.c b/net/ipv4/udp_offload.c
index 6401574..f4f616e 100644 (file)
--- a/net/ipv4/udp_offload.c
+++ b/net/ipv4/udp_offload.c
@@ -205,6 +205,9 @@ static struct sk_buff *udp4_ufo_fragment(struct sk_buff *skb,
                goto out;
        }
 
+       if (!(skb_shinfo(skb)->gso_type & SKB_GSO_UDP))
+               goto out;
+
        if (!pskb_may_pull(skb, sizeof(struct udphdr)))
                goto out;
 

diff --git a/net/ipv6/tcpv6_offload.c b/net/ipv6/tcpv6_offload.c
index d883c92..278e49c 100644 (file)
--- a/net/ipv6/tcpv6_offload.c
+++ b/net/ipv6/tcpv6_offload.c
@@ -46,6 +46,9 @@ static struct sk_buff *tcp6_gso_segment(struct sk_buff *skb,
 {
        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);
 

diff --git a/net/ipv6/udp_offload.c b/net/ipv6/udp_offload.c
index e7d378c..2bd2087 100644 (file)
--- a/net/ipv6/udp_offload.c
+++ b/net/ipv6/udp_offload.c
@@ -55,6 +55,9 @@ static struct sk_buff *udp6_ufo_fragment(struct sk_buff *skb,
                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;
 

diff --git a/net/sctp/offload.c b/net/sctp/offload.c
index 4f5a2b5..6300f28 100644 (file)
--- a/net/sctp/offload.c
+++ b/net/sctp/offload.c
@@ -44,6 +44,9 @@ static struct sk_buff *sctp_gso_segment(struct sk_buff *skb,
        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;