RFC 4890 has the following text:

  The HMAC algorithm based on SHA-1 MUST be supported and
  included in the HMAC-ALGO parameter.

As a result, we need to check in sctp_verify_param() that HMAC_SHA1 is
present in the list.  If not, we should probably treat this as a
protocol violation.

It should also be a protocol violation if the HMAC parameter is empty.
Signed-off-by: NWei Yongjun <yjwei@cn.fujitsu.com>
Signed-off-by: NVlad Yasevich <vladislav.yasevich@hp.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>