gro: check invalid TCP header length

gro: check invalid TCP header length

When the TCP header length of input packets is invalid (i.e., less
than 20 bytes or greater than 60 bytes), check_seq_option() will
access illegal memory area when compare TCP Options, which may
cause a segmentation fault.

This patch adds missing invalid TCP header length check to avoid
illegal memory accesses.

Fixes: 0d2cbe59b719 ("lib/gro: support TCP/IPv4")
Fixes: 9e0b9d2ec0f4 ("gro: support VxLAN GRO")
Cc: stable@dpdk.org
Signed-off-by: Jiayu Hu <jiayu.hu@intel.com>
Tested-by: Yinan Wang <yinan.wang@intel.com>
Acked-by: Konstantin Ananyev <konstantin.ananyev@intel.com>