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Issue #2084

When AES-GCM is used for ESP then HMAC is not showed in ipsec status.

Added by Jiri Zendulka almost 6 years ago. Updated almost 6 years ago.

Status:
Closed
Priority:
Normal
Assignee:
Tobias Brunner
Category:
configuration
Affected version:
5.4.0
Resolution:
No change required

Description

Hi,

I performed some test with aes-gcm ciphers. I noticed that type of HMAC is not showed for ESP. For IKE is HMAC showed. Is it an intention?

Security Associations (1 up, 0 connecting):
      ipsec2[1]: ESTABLISHED 4 minutes ago, 89.24.2.56[responder]...37.48.4.134[initiator]
      ipsec2[1]: IKEv2 SPIs: 8fea36dcf9db484c_i b04244455a96a346_r*, pre-shared key reauthentication in 45 minutes
      ipsec2[1]: IKE proposal: AES_GCM_16_128/PRF_HMAC_SHA1/MODP_1024
      ipsec2{1}:  INSTALLED, TUNNEL, reqid 1, ESP in UDP SPIs: c29ae6a5_i c9cb68b1_o
      ipsec2{1}:  AES_GCM_16_256, 24108 bytes_i (287 pkts, 0s ago), 24108 bytes_o (287 pkts, 0s ago), rekeying in 39 minutes
      ipsec2{1}:   192.168.7.0/24 === 192.168.6.0/24

Thanks

History

#1 Updated by Tobias Brunner almost 6 years ago

  • Status changed from New to Feedback

I noticed that type of HMAC is not showed for ESP. For IKE is HMAC showed. Is it an intention?

Of course. If you use an AEAD cipher like AES-GCM there is no separate integrity algorithm. What's listed for IKE is the PRF function used for the key derivation.

#2 Updated by Jiri Zendulka almost 6 years ago

Ok, if AES_GCM is used for ESP then no hash settings is needed.

Correct esp settings in ipsec.conf should be similar like this:

...
esp=aes256gcm16-modp6144
...

I am right?

Thanks.

#3 Updated by Tobias Brunner almost 6 years ago

  • Category set to configuration
  • Status changed from Feedback to Closed
  • Assignee set to Tobias Brunner
  • Resolution set to No change required

I am right?

Yep.

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