Catcrafts/imsd
Watch
2
0
Fork
You've already forked imsd
 0
Code Issues Pull requests Projects Releases Packages 1 Wiki Activity Actions

messages: sign our requests with the public identity, not the IMSI IMPU

Browse source 
Every request we originated — INVITE, CANCEL, both ACKs, in-dialog BYE and
friends — put the IMSI-derived temporary IMPU in From. 3GPP allows that
identity in REGISTER only; the same lesson was learned for the reg-event
SUBSCRIBE (480) and never carried to calls. Most P-CSCFs overwrite From
and hid it; a Telia node did not, and a reporter's IMSI appeared on the
callee's screen (field report 2026-09-01). A strict P-CSCF may reject the
INVITE outright.

CallerId(): the registered sip: public identity (P-Associated-URI), else
the tel: one, and the temporary IMPU only before either is learned. One
helper feeds all five builders, so a dialog's From never drifts. As UAS the
dialog's local URI is the INVITE's To (RFC 3261 12.2.1.1), stored on the
Dialog, so an incoming call's BYE is signed the way the network addressed
us. The identity is persisted in the state file and restored on warm
resume, so a call placed before the refresh 200 re-learns it cannot fall
back. DUMP_SIP now also writes the last outgoing INVITE
(imsd-invite-out.raw): the one request a field log could never show.

The byte-pinned INVITE fixture moves to the tel: identity its test context
knows; new scenarios cover the sip: identity, the tel: fallback, the
pre-learning case and the UAS BYE.

Bench-verified on KPN 2026-09-08: outgoing INVITE From is the registered
sip: identity, call accepted and carried; caller ID at the far end
unchanged.
This commit is contained in:
Jorijn van der Graaf 2026-09-08 20:37:47 +02:00
commit 7978b94502
6 changed files with 97 additions and 16 deletions
Download patch file Download diff file Expand all files Collapse all files

24
implementations/main.cpp
View file

@ -411,12 +411,12 @@ std::string StateDir() {
// tiny JSON reader/writer for the persisted registration context.
std::string StatePath() { return EnvOr("STATE_FILE", std::format("{}/imsreg.state", StateDir())); }
void PersistState(const RegState& r, const std::string& route, const std::string& ppi) {
void PersistState(const RegState& r, const std::string& route, const std::string& ppi, const std::string& aor) {
std::string j = std::format(
"{{\"callid\": \"{}\", \"ftag\": \"{}\", \"cseq\": {}, \"spi_uc\": {}, "
"\"spi_us\": {}, \"expiry\": {}, \"route\": \"{}\", \"ppi\": \"{}\", "
"\"contact_user\": \"{}\"}}",
r.callid, r.ftag, r.cseq, r.spiUc, r.spiUs, r.expiry, route, ppi,
"\"aor\": \"{}\", \"contact_user\": \"{}\"}}",
r.callid, r.ftag, r.cseq, r.spiUc, r.spiUs, r.expiry, route, ppi, aor,
r.contactUser);
std::string path = StatePath();
std::error_code ec;
@ -441,7 +441,7 @@ void DumpRaw(std::string_view name, std::string_view msg) {
}
struct PersistedState {
std::optional<std::string> callid, ftag, route, ppi, contactUser;
std::optional<std::string> callid, ftag, route, ppi, aor, contactUser;
std::optional<long> cseq, spiUc, spiUs, expiry;
};
std::optional<PersistedState> LoadState() {
@ -456,6 +456,7 @@ std::optional<PersistedState> LoadState() {
ps.ftag = QuotedAfter(s, "\"ftag\": \"");
ps.route = QuotedAfter(s, "\"route\": \"");
ps.ppi = QuotedAfter(s, "\"ppi\": \"");
ps.aor = QuotedAfter(s, "\"aor\": \"");
ps.contactUser = QuotedAfter(s, "\"contact_user\": \"");
ps.cseq = IntAfter(s, "\"cseq\": ");
ps.spiUc = IntAfter(s, "\"spi_uc\": ");
@ -809,6 +810,10 @@ private:
// is re-learned from the next 200's P-Associated-URI.
ppi_ = ps->ppi.value_or("");
ss_ = sa->securityServer;
// The public identity our requests are signed with (From) — restored
// here so a call placed before the refresh 200 re-learns it does not
// fall back to the barred temporary IMPU.
ctx_.aor = ps->aor.value_or("");
ctx_.route = route_; ctx_.ppi = ppi_; ctx_.securityServer = ss_;
ctx_.portUc = PortUc; ctx_.portUs = PortUs;
Log(std::format("RESUME via existing SA (cseq {})", ps->cseq.value_or(1)));
@ -834,7 +839,7 @@ private:
if (auto e = imsd::sip::GrantedExpires(okMsg)) reg_.expiry = *e;
UpdateRouteAndPpi(okMsg);
LogBindings(okMsg);
PersistState(reg_, route_, ppi_);
PersistState(reg_, route_, ppi_, ctx_.aor);
Log("REGISTERED (resumed + true-refreshed)");
return true;
}
@ -933,7 +938,7 @@ private:
LogBindings(ok);
if (route_.empty()) route_ = std::format("<sip:{};lr>", imsd::util::HostPort(pcscf_, portPs));
ctx_.route = route_; ctx_.ppi = ppi_;
PersistState(reg_, route_, ppi_);
PersistState(reg_, route_, ppi_, ctx_.aor);
Log("REGISTERED (fresh)");
}
@ -1051,7 +1056,7 @@ private:
auto [msg, used] = Reregister(reg_.callid, reg_.ftag, reg_.cseq + 1, reg_.spiUc, reg_.spiUs);
reg_.cseq = used;
if (auto e = imsd::sip::GrantedExpires(msg)) reg_.expiry = *e;
PersistState(reg_, route_, ppi_);
PersistState(reg_, route_, ppi_, ctx_.aor);
Log(std::format("keepalive re-REGISTER ok (cseq {})", used));
SubscribeRegEvent();
if (!registered_) { registered_ = true; EmitStatus(true); }
@ -1087,7 +1092,7 @@ private:
if (auto e = imsd::sip::GrantedExpires(msg)) reg_.expiry = *e;
UpdateRouteAndPpi(msg);
LogBindings(msg);
PersistState(reg_, route_, ppi_);
PersistState(reg_, route_, ppi_, ctx_.aor);
Log("reconnected + re-registered");
SubscribeRegEvent();
if (!registered_) { registered_ = true; EmitStatus(true); }
@ -1242,6 +1247,9 @@ private:
for (const auto& a : actions) {
switch (a.type) {
case T::SendClient:
// the outgoing INVITE is the one request a field log could
// never show (DUMP_SIP dumped inbound messages only)
if (a.text.starts_with("INVITE ")) DumpRaw("imsd-invite-out.raw", a.text);
if (!sip_.Send(a.text)) { sendOk = false; Log("client send failed"); }
break;
case T::SendResponse: