This fixes several issues that came up via BSI's Certification Path
Validation Test Tool (CPT):
1) In compliance with RFC 4945, section 5.1.3.2, we now enforce that a
certificate used for IKE authentication either does not contain a keyUsage
extension (like the ones produced by pki --issue) or that they include
digitalSignature or nonRepudiation.
2) CRLs that are not yet valid are now rejected as that could be a
problem in scenarios where expired certificates are removed from CRLs and
the clock on the host doing the revocation check is trailing behind that
of the host issuing CRLs.
3) Results other than revocation (e.g. a skipped check because the CRL
couldn't be fetched) are now stored also for intermediate CA certificates
and not only for end-entity certificates, so a strict CRL policy can be
enforced in such cases.
If the certificate is revoked, we immediately returned and the chain was
invalid, however, if we couldn't fetch the CRL that result was not stored
for intermediate CAs and we weren't able to enforce a strict CRL policy
later.
Using such CRLs can be a problem if the clock on the host doing the
revocation check is trailing behind that of the host issuing CRLs in
scenarios where expired certificates are removed from CRLs. As revoked
certificates that expired will then not be part of new CRLs a host with
trailing clock might still accept such a certificate if it is still
valid according to its system clock but is not contained anymore in the
not yet valid CRL.
According to RFC 4945, section 5.1.3.2, a certificate for IKE must
either not contain the keyUsage extension, or, if it does, have at least
one of the digitalSignature or nonReputiation bits set.
Fixes some issues in the dhcp plugin like avoiding ICMP port unreachables
when setting a specific server address, or increasing the maximum size for
options e.g. for DNs in the client identifier option. The latter is also
only sent now if identity_lease is enabled (for most DHCP servers it
serves the same function as a unique MAC address does).
The client identifier serves as unique identifier just like a unique MAC
address would, so even with identity_leases disabled some DHCP servers
might assign unique leases per identity.
This increases the chances that subject DNs that might have been cut
off with the arbitrary previous limit of 64 bytes might now be sent
successfully.
The REQUEST message has the most static overhead in terms of other
options (17 bytes) as compared to DISCOVER (5) and RELEASE (7).
Added to that are 3 bytes for the DHCP message type, which means we have
288 bytes left for the two options based on the client identity (host
name and client identification). Since both contain the same value, a
FQDN identity, which causes a host name option to get added, may be
142 bytes long, other identities like subject DNs may be 255 bytes
long (the maximum for a DHCP option).
According to RFC 2131, the minimum size of the 'options' field is 312
bytes, including the 4 byte magic cookie. There also does not seem to
be any restriction regarding the message length, previously the length
was rounded to a multiple of 64 bytes. The latter might have been
because in BOOTP the options field (or rather vendor-specific area as it
was called back then) had a fixed length of 64 bytes (so max(optlen+4, 64)
might actually have been what was intended), but for DHCP the field is
explicitly variable length, so I don't think it's necessary to pad it.
Since we won't read from the socket reducing the receive buffer saves
some memory and it should also minimize the impact on other processes that
bind the same port (Linux distributes packets to the sockets round-robin).
DHCP servers will respond to port 67 if giaddr is non-zero, which we set
if we are not broadcasting. While such messages are received fine via
RAW socket the kernel will respond with an ICMP port unreachable if no
socket is bound to that port. Instead of opening a dummy socket on port
67 just to avoid the ICMPs we can also just operate with a single
socket, bind it to port 67 and send our requests from that port.
Since SO_REUSEADDR behaves on Linux like SO_REUSEPORT does on other
systems we can bind that port even if a DHCP server is running on the
same host as the daemon (this might have to be adapted to make this work
on other systems, but due to the raw socket the plugin is not that portable
anyway).
The previous code compared the port in the packet to the client port and, if
successful, checked it also against the server port, which, therefore, never
matched, but due to incorrect offsets did skip the BPF_JA. If the client port
didn't match the code also skipped to the instruction after the BPF_JA.
However, the latter was incorrect also and processing would have continued at
the next instruction anyway. Basically, DHCP packets to any port were accepted.
What's not fixed with this is that the kernel returns an ICMP Port
unreachable for packets sent to the server port (67) because we don't
have a socket bound to it.
Fixes: f0212e8837 ("Accept DHCP replies on bootps port, as we act as a relay agent if server address configured")
This patch allows for giving strongSwan only the runtime capabilities it
needs, rather than full root privileges.
Adds preprocessor directives which allow strongSwan to be configured to
1) start up as a non-root user
2) avoid modprobe()'ing IPsec kernel modules into the kernel, which
would normally require root or CAP_SYS_MODULE
Additionally, some small mods to charon/libstrongswan ensure that charon
fully supports starting as a non-root user.
Tested with strongSwan 5.5.3.
We don't have MOBIKE and the fallback to reauthentication does also not
make much sense as that doesn't affect the CHILD_SAs for IKEv1. So
instead of complicating the code we just ignore roam events for IKEv1
for now.
Closesstrongswan/strongswan#100.
In very early versions routed CHILD_SAs were attached to IKE_SAs, since
that's not the case anymore (they are handled via trap manager), we can
remove this special handling.
This algorithm uses a fixed-length key and we MUST NOT send a key length
attribute when proposing such algorithms.
While we could accept transforms with key length this would only work as
responder, as original initiator it wouldn't because we won't know if a
peer requires the key length. And as exchange initiator (e.g. for
rekeyings), while being original responder, we'd have to go to great
lengths to store the condition and modify the sent proposal to patch in
the key length. This doesn't seem worth it for only a partial fix.
This means, however, that ChaCha20/Poly1305 can't be used with previous
releases (5.3.3 an newer) that don't contain this fix.
Fixes#2614.
Fixes: 3232c0e64e ("Merge branch 'chapoly'")
Since these are installed overlapping (like during a rekeying) we have to use
the same (unique) marks (and possibly reqid) that were used previously,
otherwise, the policy installation will fail.
Fixes#2610.
If the responder is behind a NAT that remaps the response from the
statically forwarded port 500 to a new external port (as Azure seems to be
doing) we should still switch to port 4500 if we used port 500 so far as
it would not have been possible to send any messages to it if it wasn't
really port 500 (we only add a non-ESP marker if neither port is 500).
This helps to distinguish between port and protocol if only one of them
is set. If no protocol is set it's printed as 0, if the traffic
selector covers any port (0-65535) the slash that separates the two values
and the port is omitted.
This adds a new state for CHILD_SAs that we deleted but still keep
around to process delayed packets (IKEv2 only). This allows us to treat
them specially in some cases (e.g. to avoid triggering child_updown()
events as we already did that when we deleted such SAs).
Closesstrongswan/strongswan#93.
If a Quick mode is initiated for a CHILD_SA that is already installed
we can identify this situation and rekey the already installed CHILD_SA.
Otherwise we end up with several CHILD_SAs in state INSTALLED which
means multiple calls of child_updown are done. Unfortunately,
the deduplication code later does not call child_updown() (so up and down
were not even).
Closesstrongswan/strongswan#95.
Tobias Brunner