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gso: validate gso_type in GSO handlers

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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: 90017accff ("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>
This commit is contained in:
Willem de Bruijn 2018-01-19 09:29:18 -05:00 committed by David S. Miller
parent 7c68d1a6b4
commit 121d57af30
7 changed files with 21 additions and 0 deletions
repo.diff.show_diff_stats Download patch file Download diff file Expand all files Collapse all files

3
net/ipv4/esp4_offload.c
View file

@ -122,6 +122,9 @@ static struct sk_buff *esp4_gso_segment(struct sk_buff *skb,
if (!xo) if (!xo)
goto out; goto out;
if (!(skb_shinfo(skb)->gso_type & SKB_GSO_ESP))
goto out;
seq = xo->seq.low; seq = xo->seq.low;
x = skb->sp->xvec[skb->sp->len - 1]; x = skb->sp->xvec[skb->sp->len - 1];

3
net/ipv4/tcp_offload.c
View file

@ -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, static struct sk_buff *tcp4_gso_segment(struct sk_buff *skb,
netdev_features_t features) 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))) if (!pskb_may_pull(skb, sizeof(struct tcphdr)))
return ERR_PTR(-EINVAL); return ERR_PTR(-EINVAL);

3
net/ipv4/udp_offload.c
View file

@ -203,6 +203,9 @@ static struct sk_buff *udp4_ufo_fragment(struct sk_buff *skb,
goto out; goto out;
} }
if (!(skb_shinfo(skb)->gso_type & SKB_GSO_UDP))
goto out;
if (!pskb_may_pull(skb, sizeof(struct udphdr))) if (!pskb_may_pull(skb, sizeof(struct udphdr)))
goto out; goto out;

3
net/ipv6/esp6_offload.c
View file

@ -149,6 +149,9 @@ static struct sk_buff *esp6_gso_segment(struct sk_buff *skb,
if (!xo) if (!xo)
goto out; goto out;
if (!(skb_shinfo(skb)->gso_type & SKB_GSO_ESP))
goto out;
seq = xo->seq.low; seq = xo->seq.low;
x = skb->sp->xvec[skb->sp->len - 1]; x = skb->sp->xvec[skb->sp->len - 1];

3
net/ipv6/tcpv6_offload.c
View file

@ -46,6 +46,9 @@ static struct sk_buff *tcp6_gso_segment(struct sk_buff *skb,
{ {
struct tcphdr *th; struct tcphdr *th;
if (!(skb_shinfo(skb)->gso_type & SKB_GSO_TCPV6))
return ERR_PTR(-EINVAL);
if (!pskb_may_pull(skb, sizeof(*th))) if (!pskb_may_pull(skb, sizeof(*th)))
return ERR_PTR(-EINVAL); return ERR_PTR(-EINVAL);

3
net/ipv6/udp_offload.c
View file

@ -42,6 +42,9 @@ static struct sk_buff *udp6_ufo_fragment(struct sk_buff *skb,
const struct ipv6hdr *ipv6h; const struct ipv6hdr *ipv6h;
struct udphdr *uh; struct udphdr *uh;
if (!(skb_shinfo(skb)->gso_type & SKB_GSO_UDP))
goto out;
if (!pskb_may_pull(skb, sizeof(struct udphdr))) if (!pskb_may_pull(skb, sizeof(struct udphdr)))
goto out; goto out;

3
net/sctp/offload.c
View file

@ -45,6 +45,9 @@ static struct sk_buff *sctp_gso_segment(struct sk_buff *skb,
struct sk_buff *segs = ERR_PTR(-EINVAL); struct sk_buff *segs = ERR_PTR(-EINVAL);
struct sctphdr *sh; struct sctphdr *sh;
if (!(skb_shinfo(skb)->gso_type & SKB_GSO_SCTP))
goto out;
sh = sctp_hdr(skb); sh = sctp_hdr(skb);
if (!pskb_may_pull(skb, sizeof(*sh))) if (!pskb_may_pull(skb, sizeof(*sh)))
goto out; goto out;