[CVE-2017-12470] ndn_parse_sequence: integer overflow

[blacksheeep]

static int
ndn_parse_sequence(int lev, unsigned char *base, unsigned char **buf,
int *len, char cur_tag, int rawxml, FILE out)
{
int i, maxi, vallen;
int typ;

typ should be unsigned, otherwise the check below fails:

    if (typ < NDN_TLV_MAX_TYPE && ndntlv_recurse[typ]) {
        *len -= vallen;

vallen wants to be unsigned as well, or better size_t

[blacksheeep]

fixed in ccnlv2-master