If charon.prefer_configured_proposals is disabled select() is called on
the received proposal. This incorrectly set the SPI to 0 as the
configured proposal has no SPI set.
Fixes#2190.
Recent research demonstrates that at least for 1024-bit DH groups, it is
possible to create specially crafted primes having a backdoor. From the
prime itself this is not detectable, creating a perfect NOBUS attack.
http://eprint.iacr.org/2016/961
For the primes defined in RFC 5114 no information is provided on how these
have been selected. In the default proposal we included one of the 2048-bit
primes only, where it is questionable if constructing a backdoored prime is
feasible. Nevertheless, this patch removes the group from the set of default
proposals as well.
We parse aes*gmac as encryption algorithm, which we have to map to an
integrity algorithm. We also make sure we remove all other encryption
algorithms and ensure there is an integrity algorithm.
This fixes an interoperability issue with Windows Server 2012 R2 gateways.
They insist on using modp1024 for IKE, however, Microsoft's IKEv2
implementation seems only to consider the first 15 DH groups in the proposal.
Depending on the loaded plugins modp1024 is now at position 17 or even
later, causing the server to reject the proposal. By removing some of
the weaker and rarely used DH groups from the default proposal we make
sure modp1024 is among the first 15 DH groups. The removed groups may
still be used by configuring custom proposals.
If DPD timeout is set but to a value smaller than the DPD delay the code
in task_manager_v1.c:queue_liveliness_check will run into an integer
underrun.
The default ESP cipher suite is now
AES_CBC-128/HMAC_SHA2_256_128
and requires SHA-2 HMAC support in the Linux kernel (correctly implemented
since 2.6.33).
The default IKE cipher suite is now
AES_CBC-128/HMAC_SHA2_256_128/PRF_HMAC_SHA2_256/ECP_256
if the openssl plugin is loaded or
AES_CBC-128/HMAC_SHA2_256_128/PRF_HMAC_SHA2_256/MODP_3072
if ECC is not available.
The use of the SHA-1 hash algorithm and the MODP_2048 DH group has been
deprecated and ENCR_CHACHA20_POLY1305 has been added to the default
IKE AEAD algorithms.
According to RFC 5996 3.3 we should use a separate proposal for AEAD algorithms.
This was not clear in RFC 5282, hence we previously included both AEAD and
non-AEAD algorithms in a single proposal.
The DH transform is optional for ESP/AH proposals. The initiator can
include NONE (0) in its proposal to indicate that while it prefers to
do a DH exchange, the responder may still decide to not do so.
Fixes#532.
Tobias Brunner