Enviar #808485: Open5gs SMF v2.7.7 Denial of Service

### Open5GS Release, Revision, or Tag

v2.7.7

### Steps to reproduce

### Description

When SMF operates in the home-routed V-SMF role and receives a
`201 Created` response for `POST /nsmf-pdusession/v1/pdu-sessions`, it aborts
if `PduSessionCreatedData` omits `qosFlowsSetupList`.

The response handler stores `sess->h_smf_qos_flows_setup_list` only if the
received list exists and has at least one item:

```c
qosFlowsSetupList = OpenAPI_list_create();
...
if (qosFlowsSetupList->count)
sess->h_smf_qos_flows_setup_list = qosFlowsSetupList;
else
OpenAPI_list_free(qosFlowsSetupList);
```

But the later NAS builder for HR V-SMF unconditionally asserts that the list is
present:

```c
if (HOME_ROUTED_ROAMING_IN_VSMF(sess)) {
qosFlowsSetupList = sess->h_smf_qos_flows_setup_list;
ogs_assert(qosFlowsSetupList);
```

So a crafted H-SMF `201 Created` response with valid earlier fields but no
`qosFlowsSetupList` leads to a fatal assertion in
`gsm_build_pdu_session_establishment_accept()`.

This issue is distinct from the related `missing hcnTunnelInfo` response-path
crash. Here `hcnTunnelInfo` is present and valid; the abort happens later
during NAS construction.

### Steps to reproduce

1. Run a fake H-SMF h2c server on `10.33.33.1:18083` that answers
`POST /nsmf-pdusession/v1/pdu-sessions` with:

- HTTP status `201`
- `Location: http://10.33.33.1:18083/nsmf-pdusession/v1/pdu-sessions/fake-3`
- a multipart body containing JSON `PduSessionCreatedData` with:
- `n1SmInfoToUe`
- `pduSessionType: "IPV4"`
- `sscMode: "1"`
- `ueIpv4Address`
- valid `hcnTunnelInfo`
- but no `qosFlowsSetupList`

2. Send `POST /nsmf-pdusession/v1/sm-contexts` to the local SMF with:

- a full DNN such as `internet.mnc001.mcc001.gprs`
- `hSmfUri` pointing to the fake H-SMF
- minimal `n1SmMsg` payload `c191a1`

3. Wait for the fake H-SMF to log:

```text
REQ POST /nsmf-pdusession/v1/pdu-sessions
RESP sent 322
```

4. Check SMF state and logs:

```bash
docker inspect -f '{{.State.Status}} {{.State.ExitCode}} {{.State.FinishedAt}}' smf
docker logs --since 2026-04-11T05:46:54Z smf
```

### Logs

```shell
Fake H-SMF log:

REQ POST /nsmf-pdusession/v1/pdu-sessions
BODYLEN 691
RESP sent 322

SMF state:

exited 139 2026-04-11T05:47:13.014793159Z

SMF log:

04/11 05:47:12.916: [smf] INFO: Setup NF EndPoint(addr) [10.33.33.1:18083] (../src/smf/nsmf-handler.c:2040)
04/11 05:47:12.916: [smf] INFO: UE SUPI[imsi-001011234567895] DNN[internet] S_NSSAI[SST:1 SD:0xffffff] pduSessionRef[fake-3] pduSessionResourceURI[http://10.33.33.1:18083/nsmf-pdusession/v1/pdu-sessions/fake-3] (../src/smf/nsmf-handler.c:2078)
04/11 05:47:12.918: [gsm] FATAL: gsm_build_pdu_session_establishment_accept: Assertion `qosFlowsSetupList' failed. (../src/smf/gsm-build.c:101)
```

### Expected behaviour

SMF should reject the malformed `PduSessionCreatedData` response and terminate only the affected transaction.

### Observed Behaviour

The crafted H-SMF response aborts the entire SMF process with exit code `139`.

### eNodeB/gNodeB

Not required.

### UE Models and versions

Not required.

• Fuente: ⚠️ https://github.com/open5gs/open5gs/issues/4449
• Usuario: FrankLin (UID 97501)
• Sumisión: 2026-04-20 21:21 (hace 2 meses)
• Moderación: 2026-05-10 17:44 (20 days later)
• Estado: Aceptado
• Entrada de VulDB: 362565 [Open5GS hasta 2.7.7 SMF OpenAPI_list_create denegación de servicio]
• Puntos: 20