1. Reachable assertion in ogs_nas_5gmm_decode
Location: lib/nas/5gs/decoder.c:4445
```c
int ogs_nas_5gmm_decode(ogs_nas_5gs_message_t *message, ogs_pkbuf_t *pkbuf)
{
int size = 0;
int decoded = 0;
ogs_assert(pkbuf);
ogs_assert(pkbuf->data);
ogs_assert(pkbuf->len);
```
When a NAS payload is received over `src/amf/context.c:1675`NGAP that has no data, the ogs_assert(pkbuf->len) assertion will be triggered.
2.Reachable assertion in ogs_nas_emm_decode
```
int ogs_nas_emm_decode(ogs_nas_eps_message_t *message, ogs_pkbuf_t *pkbuf)
{
int size = 0;
int decoded = 0;
ogs_assert(pkbuf);
ogs_assert(pkbuf->data);
ogs_assert(pkbuf->len);
```
Nearly identical to (1), but for LTE.
3. Reachable assertion in nas_eps_send_emm_to_esm
```
int nas_eps_send_emm_to_esm(mme_ue_t *mme_ue,
ogs_nas_esm_message_container_t *esm_message_container)
{
int rv;
ogs_pkbuf_t *esmbuf = NULL;
if (!mme_ue_cycle(mme_ue)) {
ogs_error("UE(mme-ue) context has already been removed");
return OGS_NOTFOUND;
}
ogs_assert(esm_message_container);
ogs_assert(esm_message_container->length);
```
The ESM message payload may be 0-length, as the length is determined by a field in the NAS payload (which can be chosen arbitrarily by an attacker). This leads to the length assertion above being triggered.
5. Reachable assertion and incorrect hash calculation in ogs_kdf_hash_mme
```
void ogs_kdf_hash_mme(const uint8_t *message, uint8_t message_len, uint8_t *hash_mme)
{
uint8_t key[32];
uint8_t output[OGS_SHA256_DIGEST_SIZE];
ogs_assert(message);
ogs_assert(message_len);
ogs_assert(hash_mme);
memset(key, 0, 32);
ogs_hmac_sha256(key, 32, message, message_len,
output, OGS_SHA256_DIGEST_SIZE);
memcpy(hash_mme, output+24, OGS_HASH_MME_LEN);
}
```
When handling NAS attach requests or TAU requests, the ogs_kdf_hash_mme function is passed the NAS payload. However, the length field is represented as an unsigned 8-bit integer, which the passed length of the packet may overflow. This leads to the passed value being truncated.
When the passed value is a multiple of 256, the above assertion (ogs_assert(message_len)) is triggered. Otherwise, the hash is computed on only the first n bits of the message (where n = actual_message_len % 256).
o Generate the private key as below.
$ openssl genpkey -algorithm X25519 -out /etc/open5gs/hnet/curve25519-1.key
$ openssl ecparam -name prime256v1 -genkey -conv_form compressed -out /etc/open5gs/hnet/secp256r1-2.key
o The private and public keys can be viewed with the command.
The public key is used when creating the SIM.
$ openssl pkey -in /etc/open5gs/hnet/curve25519-1.key -text
$ openssl ec -in /etc/open5gs/hnet/secp256r1-2.key -conv_form compressed -text
In ausf/udm.yaml
hnet:
o Home network public key identifier(PKI) value : 1
Protection scheme identifier : ECIES scheme profile A
- id: 1
scheme: 1
key: /etc/open5gs/hnet/curve25519-1.key
o Home network public key identifier(PKI) value : 2
Protection scheme identifier : ECIES scheme profile B
- id: 2
scheme: 2
key: /etc/open5gs/hnet/secp256r1-2.key
o Home network public key identifier(PKI) value : 3
Protection scheme identifier : ECIES scheme profile A
- id: 3
scheme: 1
key: /etc/open5gs/hnet/curve25519-1.key
o Home network public key identifier(PKI) value : 4
Protection scheme identifier : ECIES scheme profile B
- id: 4
scheme: 2
key: /etc/open5gs/hnet/secp256r1-2.key
Related to #1779
When a UE that requests slices tries to connect and there are no slices configured, the reject message is:
5GMM cause = 0x7 (5GS Services not allowed)
however it should be:
5GMM cause = 0x3e (No network slices available)
All 5GMM cause value in reject message is reviewed in this commit
For null protection scheme the SUCI needs to be BCD encoded. Whereas for
protection scheme profiles A and B the SUCI needs to be converted from
hexadecimal to ASCII.
This still needs the support for protection schemes A and B in UDM to
work.
When connecting to the UPF port for the PFCP protocol (8805) and sending
an association setup request followed by a session establishment request
with a PDI Network Instance set to ‘internet’, it causes a stack corruption
to occur.
So, ogs_fqdn_parse() fixed.
If parameter.ignore_requsted_nssai is true,
AMF will ignore the UE Requested NSSAI and create an allowed-NSSAI
based on the Default S-NSSAI in the Subscription DB.
Sukchan Lee
Bostjan Meglic
Bostjan Meglic