cifs: parse_dfs_referrals: prevent oob on malformed input

In the Linux kernel, the following vulnerability has been resolved: cifs: parse_dfs_referrals: prevent oob on malformed input Malicious SMB server can send invalid reply to FSCTL_DFS_GET_REFERRALS - reply smaller than sizeof(struct get_dfs_referral_rsp) - reply with number of referrals smaller than NumberOfReferrals in the header Processing of such replies will cause oob. Return -EINVAL error on such replies to prevent oob-s.