diff options
| author | Willem de Bruijn <willemb@google.com> | 2019-02-15 12:15:47 -0500 |
|---|---|---|
| committer | Greg Kroah-Hartman <gregkh@linuxfoundation.org> | 2019-02-27 10:08:08 +0100 |
| commit | dac7d4432b13d6b58923c1178b786bcda37c9e9e (patch) | |
| tree | 47d4bc65859e10693ee5d5323b8e83d89e56b375 /include/linux/virtio_net.h | |
| parent | 6964c1d5062de1fb26864f59b41a5ad00f641db9 (diff) | |
net: validate untrusted gso packets without csum offload
commit d5be7f632bad0f489879eed0ff4b99bd7fe0b74c upstream.
Syzkaller again found a path to a kernel crash through bad gso input.
By building an excessively large packet to cause an skb field to wrap.
If VIRTIO_NET_HDR_F_NEEDS_CSUM was set this would have been dropped in
skb_partial_csum_set.
GSO packets that do not set checksum offload are suspicious and rare.
Most callers of virtio_net_hdr_to_skb already pass them to
skb_probe_transport_header.
Move that test forward, change it to detect parse failure and drop
packets on failure as those cleary are not one of the legitimate
VIRTIO_NET_HDR_GSO types.
Fixes: bfd5f4a3d605 ("packet: Add GSO/csum offload support.")
Fixes: f43798c27684 ("tun: Allow GSO using virtio_net_hdr")
Reported-by: syzbot <syzkaller@googlegroups.com>
Signed-off-by: Willem de Bruijn <willemb@google.com>
Reviewed-by: Eric Dumazet <edumazet@google.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Diffstat (limited to 'include/linux/virtio_net.h')
| -rw-r--r-- | include/linux/virtio_net.h | 9 |
1 files changed, 9 insertions, 0 deletions
diff --git a/include/linux/virtio_net.h b/include/linux/virtio_net.h index cb462f9ab7dd..71f2394abbf7 100644 --- a/include/linux/virtio_net.h +++ b/include/linux/virtio_net.h @@ -57,6 +57,15 @@ static inline int virtio_net_hdr_to_skb(struct sk_buff *skb, if (!skb_partial_csum_set(skb, start, off)) return -EINVAL; + } else { + /* gso packets without NEEDS_CSUM do not set transport_offset. + * probe and drop if does not match one of the above types. + */ + if (gso_type) { + skb_probe_transport_header(skb, -1); + if (!skb_transport_header_was_set(skb)) + return -EINVAL; + } } if (hdr->gso_type != VIRTIO_NET_HDR_GSO_NONE) { |