The struct allows to support multiple types of the tunneled methods.
Previously, EAP-TTLS was supporting only the eap based ones.
This patch is also starts to move some of the phase 2 EAP
functionality into the new structure.
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).
load_settings ensures that ttls->eap is correctly initialized. So this
code should be treated as an error condition.
We also do not support EAP chaining, so remove that logic as well
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.
The EAP-method's .probe methods only checked the method name so do that
in eap.c instead and allocate method state in .load_settings. Rename
method's .remove method to .free to improve the naming.
Only EAP as the inner authentication option is supported. According to
wikipedia this is the most popular EAP-TTLS use case, with MD5 as the
inner EAP's method.
