Replace the usage of eap_send_response() in the method implementations
with a new eap_method_respond that skips the redundant "type" parameter.
The new eap_send_packet is used inside eap_method_respond and will be
reused for sending request packets in authenticator side EAP methods.
The password for EAP-GTC is directly used in an EAP response. The
response buffer is created on the stack so an overly large password
could cause a stack overflow.
There are some server implementations that send requests that are
not "Password" but still want us send password. This commit modify
the behavior to send a warning and still try to auth with password.
This makes me able to auth with server in my school which sends
"Enter Aruba Login".
wpa_supplicant does not check if it is "Password".
The single-use password is apparently sent in plaintext over the network
but at least try to prevent it from staying in the memory until we know
it's been used.
A method's .check_settings method checks for inconsistent setting files
and prints readable errors so there's no need to do that again in
.load_settings, although at some point after removing the duplicate
error messages from the load_settings methods we agreed to keep minimum
checks that could cause a crash e.g. in a corner case like when the
setting file got modified between the check_settings and the
load_settings call. Some error messages have been re-added to
load_settings after that (e.g. in
bb4e1ebd4f) but they're incomplete and not
useful so remove them.
This makes testEAP-PEAP-GTC pass for me by re-adding the check for the
GTC-Secret setting which was replaced with the check for the secrets
list in 3d2285ec7e.
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).
Now, EAP-GTC behaves similar to MSCHAPv2 where check_settings allows
for missing EAP-Identity and GTC-Secret fields. Either or both can be
missing and the agent will request the missing fields.
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.
