If one peer starts reauthentication by deleting the IKE_SA, while the other
starts CHILD_SA rekeying, we run in a race condition. To avoid it, temporarily
reject the rekey attempt while we are in the IKE_SA deleting state.
RFC 4306/5996 is not exactly clear about this collision, but it should be safe
to reject CHILD_SA rekeying during this stage, as the reauth will re-trigger the
CHILD_SA. For non-rekeying CHILD_SA creations, it's up to the peer to retry
establishing the CHILD_SA on the reauthenticated IKE_SA.
The extensions and conditions apply to the rekeyed IKE_SA as well, so we should
migrate them. Especially when using algorithms from private space, we need
EXT_STRONGSWAN to properly select these algorithms during IKE rekeying.
Even in Main Mode, some Sonicwall boxes seem to send ID/HASH payloads in
unencrypted form, probably to allow PSK lookup based on the ID payloads. We
by default reject that, but accept it if the
charon.accept_unencrypted_mainmode_messages option is set in strongswan.conf.
Initial patch courtesy of Paul Stewart.
Before this change a reqid set on the create_child_t task was used as
indicator of the CHILD_SA being rekeyed. Only if that was not the case
would the local traffic selector be changed to 0.0.0.0/0|::/0 (as we
don't know which virtual IP the gateway will eventually assign).
On the other hand, in case of a rekeying the VIP is expected to remain
the same, so the local TS would simply equal the VIP.
Since c949a4d5016e33c5 reauthenticated CHILD_SAs also have the reqid
set. Which meant that the local TS would contain the previously
assigned VIP, basically rendering the gateway unable to assign a
different VIP to the client as the resulting TS would not match
the client's proposal anymore.
Fixes#553.
Prevents a responder peer to trick us into established state by starting
IKE_SA rekeying before the IKE_SA has been authenticated during IKE_AUTH.
Fixes CVE-2014-2338.
This is undefined behavior as per the C99 standard (sentence 1185):
"If the value of the right operand is negative or is greater or equal
to the width of the promoted left operand, the behavior is undefined."
Apparently shifts may be done modulo the width on some platforms so
a shift by 32 would not shift at all.
