Processing the duplicated TLVs while connecting to a malicious AP may lead
to overflow of the response buffer. This patch ensures that the
duplicated TLVs are not parsed.
For the inner EAP methods that support generation of the key material
include it into imck generation. This allows to cryptographically
bind the inner method with the tunnel.
Some server implementation don't seem to provide the valid compound MACs.
In the meantime, iwd will ignore the invalid Crypto-Binding TLVs as their
usage is optional.
The Crypto Binding TLV is used to ensure that the EAP peer and the
EAP server participated in both the inner and the outer EAP
authentications of a PEAP authentication by cryptographically associating
the phase 1 and phase 2 authentications.
The usage of Crypto-Binding in PEAPv0 is optional and is triggered by
the reception of the Crypto-Binding TLV from the server.
The handler for EAP Extensions has been modified to support multiple
TLV types instead of the single Result TLV. This will allow to handle
the other TLVs such as Crypto-Binding TLV.
Previously, the key was installed once the tunnel was created
despite the outcome of the second authentication phase. Now, the
key installation is delayed until the successful completion of
the second authentication phase. This excludes the unnecessary
operations in the case of a failure and key reinstallation with
cypro-binding in use.
Despite that PEAPv0 spec indicates that TLS tunnel needs to be torn
down after the transmission of a secure Result response, some servers
treat this TLS close alert as a failure. This patch changes the above
behavior to explicitly torn the tunnel only in the case of
authentication failure and leave it open after the success.
Some of the EAP-PEAP server implementations seem to require a
cleartext ACK for the tunneled EAP-Success message similar to EAP-TLS
specification, instead of simply shutting down the tunnel like
EAP-PEAPv1 requires.
ACKing the tunneled EAP-Success seems also to work for implementations
which were relying on the tunnel close event.
Some of the PEAP server implementations set the L flag along with
redundant TLS Message Length field for the un-fragmented packets.
This patch allows to identify and handle such occasions.
EAP Extensions type 33 is used in PEAPv0 as a termination
mechanism for the tunneled EAP methods. In PEAPv1
the regular EAP-Success/Failure packets must be used to terminate
the method. Some of the server implementations of PEAPv1
rely on EAP Extensions method to terminate the conversation
instead of the required Success/Failure packets. This patch
makes iwd interoperable with such devices.
eap_append_secret now takes a new cache_policy parameter which can be
used by the EAP method to signal that the value received from the agent
is to never be cached, i.e. each value can only be used once. The
parameter value should be EAP_CACHE_NEVER for this and we use this in
value EAP-GTC where the secret tokens are one time use. The
EAP_CACHE_TEMPORARY value is used in other methods, it preserves the
default behaviour where a secret can be cached for as long as the
network stays in range (this is the current implementation more than a
design choice I believe, I didn't go for a more specific enum name as
this may still change I suppose).
Some of the PEAP server implementation brake the protocol
and don’t set the M flag for the first packet during the
fragmented transmission. To stay compatible with such
devices, we relax this requirement in iwd.
Since PEAP & TTLS expect to use eap_check_settings recursively, make
them use a private version of that API that does not perform cleanup and
can contain side-effects.
eap_check_settings itself will guarantee that no side effects happen on
error. It is meant to be used by code outside of the eap subsystem.
Replace usages of l_settings_get_value with l_settings_get_string, which
will make sure the returned strings are unescaped but also allocates
memeory and forces us to use l_free on most of the strings. Some of
these strings we explicitly set with l_settings_set_string() in our code
so when we retrieved them with l_settings_get_value() we would receive a
different string if there were any escapable characters in the string.
I didn't replace any of the l_settings_get_value() uses where we're just
checking whether a setting is present, or those which are hexstrings or
EAP method names assuming that they can't have any special characters,
although this isn't future proof. I did use l_settings_get_string() for
file paths though.
Accept two setting IDs in eap_append_secret, first for the username and
second for the password in case of the EAP_SECRET_REMOTE_USER_PASSWORD
EAP secret type. In all other cases only the first setting is used.
Until now for EAP_SECRET_REMOTE_USER_PASSWORD secrets we'd generate the
two setting names by adding different suffixes to the ID parameter.
Using the two different setting names automatically fixes the issues
with using the EAP Identity returned by the agent in EAP-MSCHAPv2 and
EAP-PWD.
Confirm that the PEM file paths that we'll be passing to the l_tls
object are loading Ok and request/validate the private key passphrase
if needed. Then also call eap_check_settings to validate the inner
method's settings.
