/**
* Decode an SDP fingerprint value
*
* @param attr SDP attribute value
* @param hash Returned hash method
* @param md Returned message digest
* @param sz Message digest size, set on return
*
* @return 0 if success, otherwise errorcode
*
* Reference: RFC 4572
*/
int sdp_fingerprint_decode(const char *attr, struct pl *hash,
uint8_t *md, size_t *sz)
{
struct pl f;
const char *p;
int err;
if (!attr || !hash)
return EINVAL;
err = re_regex(attr, str_len(attr), "[^ ]+ [0-9A-F:]+", hash, &f);
if (err)
return err;
if (md && sz) {
if (*sz < (f.l+1)/3)
return EOVERFLOW;
for (p = f.p; p < (f.p+f.l); p += 3) {
*md++ = ch_hex(p[0]) << 4 | ch_hex(p[1]);
}
*sz = (f.l+1)/3;
}
return 0;
}
static bool nonce_validate(char *nonce, time_t now, const struct sa *src)
{
uint8_t nkey[MD5_SIZE], ckey[MD5_SIZE];
uint64_t nv[3];
struct pl pl;
int64_t age;
unsigned i;
pl.p = nonce;
pl.l = str_len(nonce);
if (pl.l < NONCE_MIN_SIZE || pl.l > NONCE_MAX_SIZE) {
restund_info("auth: bad nonce length (%zu)\n", pl.l);
return false;
}
for (i=0; i<sizeof(nkey); i++) {
nkey[i] = ch_hex(*pl.p++) << 4;
nkey[i] += ch_hex(*pl.p++);
pl.l -= 2;
}
nv[0] = pl_x64(&pl);
nv[1] = auth.secret;
nv[2] = sa_hash(src, SA_ADDR);
md5((uint8_t *)nv, sizeof(nv), ckey);
if (memcmp(nkey, ckey, MD5_SIZE)) {
restund_debug("auth: invalid nonce (%j)\n", src);
return false;
}
age = now - nv[0];
if (age < 0 || age > auth.nonce_expiry) {
restund_debug("auth: nonce expired, age: %lli secs\n", age);
return false;
}
return true;
}
static int comp_unescape(struct re_printf *pf, const struct pl *pl, esc_h *eh)
{
size_t i;
int err = 0;
if (!pf || !pl || !eh)
return EINVAL;
for (i=0; i<pl->l && !err; i++) {
const char c = pl->p[i];
if (eh(c)) {
err = pf->vph(&c, 1, pf->arg);
continue;
}
if ('%' == c) {
if (i < (pl->l - 2)) {
const uint8_t hi = ch_hex(pl->p[++i]);
const uint8_t lo = ch_hex(pl->p[++i]);
const char b = hi<<4 | lo;
err = pf->vph(&b, 1, pf->arg);
}
else {
DEBUG_WARNING("unescape: short uri (%u)\n", i);
return EBADMSG;
}
}
else {
DEBUG_WARNING("unescape: illegal '%c' in %r\n",
c, pl);
return EINVAL;
}
}
return err;
}
