PEAP client: Update Phase 2 authentication requirements

The previous PEAP client behavior allowed the server to skip Phase 2
authentication with the expectation that the server was authenticated
during Phase 1 through TLS server certificate validation. Various PEAP
specifications are not exactly clear on what the behavior on this front
is supposed to be and as such, this ended up being more flexible than
the TTLS/FAST/TEAP cases. However, this is not really ideal when
unfortunately common misconfiguration of PEAP is used in deployed
devices where the server trust root (ca_cert) is not configured or the
user has an easy option for allowing this validation step to be skipped.

Change the default PEAP client behavior to be to require Phase 2
authentication to be successfully completed for cases where TLS session
resumption is not used and the client certificate has not been
configured. Those two exceptions are the main cases where a deployed
authentication server might skip Phase 2 and as such, where a more
strict default behavior could result in undesired interoperability
issues. Requiring Phase 2 authentication will end up disabling TLS
session resumption automatically to avoid interoperability issues.

Allow Phase 2 authentication behavior to be configured with a new phase1
configuration parameter option:
'phase2_auth' option can be used to control Phase 2 (i.e., within TLS
tunnel) behavior for PEAP:
 * 0 = do not require Phase 2 authentication
 * 1 = require Phase 2 authentication when client certificate
   (private_key/client_cert) is no used and TLS session resumption was
   not used (default)
 * 2 = require Phase 2 authentication in all cases

Bug: 287119604
Test: Manual - WPA/WPA2 & WPA3 Enterprise connection
Test: Regression test b/289297084
BYPASS_INCLUSIVE_LANGUAGE_REASON=Merged from open source
Change-Id: Ibe441934a28e83b50d38e787f284bd2d16cec169
Signed-off-by: Jouni Malinen <j@w1.fi>
5 files changed