Most protocols extracting keys from TLS use RFC 5705 exporters which is
commonly implemented in TLS libraries. This is the mechanism used by
EAP-TLS. (EAP-TLS actually predates RFC 5705, but RFC 5705 was defined
to be compatible with it.)
EAP-FAST, however, uses a legacy mechanism. It reuses the TLS internal
key block derivation and derives key material after the key block. This
is uncommon and a misuse of TLS internals, so not all TLS libraries
support this. Instead, we reimplement the PRF for the OpenSSL backend
and don't support it at all in the GnuTLS one.
Since these two are very different operations, split
tls_connection_prf() in two. tls_connection_export_key() implements the
standard RFC 5705 mechanism that we expect most TLS libraries to
support. tls_connection_get_eap_fast_key() implements the
EAP-FAST-specific legacy mechanism which may not be implemented on all
backends but is only used by EAP-FAST.
Signed-Off-By: David Benjamin <davidben@google.com>
This can be used to limit TLS session resumption within a TLS library
implementation to apply only for the cases where the same EAP method is
used. While the EAP server method matching will be enforced separately
by EAP server method implementations, this additional steps can optimize
cases by falling back to full authentication instead of having to reject
attempts after having completed session resumption successfully.
Signed-off-by: Jouni Malinen <j@w1.fi>
The EAP server is not yet capable of using TLS session ticket to resume
a session. Explicitly disable use of TLS session ticket with
EAP-TLS/TTLS/PEAP to avoid wasting resources on generating a session
ticket that cannot be used for anything.
Signed-off-by: Jouni Malinen <j@w1.fi>
Commit 94f1fe6f63 ('Remove master key
extraction from tls_connection_get_keys()') left only fetching of
server/client random, but did not rename the function and structure to
minimize code changes. The only name is quite confusing, so rename this
through the repository to match the new purpose.
Signed-off-by: Jouni Malinen <j@w1.fi>
This function exposes internal state of the TLS negotiated parameters
for the sole purpose of being able to implement PRF for EAP-FAST. Since
tls_connection_prf() is now taking care of all TLS-based key derivation
cases, it is cleaner to keep this detail internal to each tls_*.c
wrapper implementation.
Signed-off-by: Jouni Malinen <jouni@qca.qualcomm.com>
tls_openssl.c is the only remaining TLS/crypto wrapper that needs the
internal PRF implementation for EAP-FAST (since
SSL_export_keying_material() is not available in older versions and does
not support server-random-before-client case). As such, it is cleaner to
assume that TLS libraries support tls_connection_prf() and move the
additional support code for the otherwise unsupported cases into
tls_openssl.c.
Signed-off-by: Jouni Malinen <jouni@qca.qualcomm.com>
The internal TLS server implementation and RADIUS server implementation
in hostapd can be configured to allow EAP clients to be tested to
perform TLS validation steps correctly. This functionality is not
included in the default build; CONFIG_TESTING_OPTIONS=y in
hostapd/.config can be used to enable this.
When enabled, the RADIUS server will configure special TLS test modes
based on the received User-Name attribute value in this format:
<user>@test-tls-<id>.<rest-of-realm>. For example,
anonymous@test-tls-1.example.com. When this special format is used, TLS
test modes are enabled. For other cases, the RADIUS server works
normally.
The following TLS test cases are enabled in this commit:
1 - break verify_data in the server Finished message
2 - break signed_params hash in ServerKeyExchange
3 - break Signature in ServerKeyExchange
Correctly behaving TLS client must abort connection if any of these
failures is detected and as such, shall not transmit continue the
session.
Signed-off-by: Jouni Malinen <j@w1.fi>
This allows the internal TLS implementation to write log entries to the
same authlog with rest of the RADIUS server and EAP server
functionality.
Signed-off-by: Jouni Malinen <j@w1.fi>
It was possible to configure hostapd in a way that could try to
initialize a TLS-based EAP method even when TLS library context was not
initialized (e.g., due to not configuring server or CA certificate).
Such a case could potentially result in NULL pointer dereference in the
TLS library, so check for this condition and reject EAP method
initialization.
Signed-hostap: Jouni Malinen <j@w1.fi>
While the existing code already addresses TLS Message Length validation
for both EAP-TLS peer and server side, this adds explicit checks and
rejection of invalid messages in the functions handling reassembly. This
does not change externally observable behavior in case of EAP server.
For EAP peer, this starts rejecting invalid messages instead of
addressing them by reallocating the buffer (i.e., ignoring TLS Message
Length in practice).
Signed-hostap: Jouni Malinen <j@w1.fi>
EAP-TLS/PEAP/TTLS/FAST server implementation did not validate TLS
Message Length value properly and could end up trying to store more
information into the message buffer than the allocated size if the first
fragment is longer than the indicated size. This could result in hostapd
process terminating in wpabuf length validation. Fix this by rejecting
messages that have invalid TLS Message Length value.
This would affect cases that use the internal EAP authentication server
in hostapd either directly with IEEE 802.1X or when using hostapd as a
RADIUS authentication server and when receiving an incorrectly
constructed EAP-TLS message. Cases where hostapd uses an external
authentication are not affected.
Thanks to Timo Warns for finding and reporting this issue.
Signed-hostap: Jouni Malinen <j@w1.fi>
intended-for: hostap-1
This EAP type uses a vendor specific expanded EAP header to encapsulate
EAP-TLS with a configuration where the EAP server does not authenticate
the EAP peer. In other words, this method includes only server
authentication. The peer is configured with only the ca_cert parameter
(similarly to other TLS-based EAP methods). This method can be used for
cases where the network provides free access to anyone, but use of RSN
with a securely derived unique PMK for each station is desired.
The expanded EAP header uses the hostapd/wpa_supplicant vendor
code 39068 and vendor type 1 to identify the UNAUTH-TLS method.
Signed-hostap: Jouni Malinen <j@w1.fi>
Prepare for multiple TLS PRF functions by renaming the SHA1+MD5 based
TLS PRF function to more specific name and add tls_prf() within the
internal TLS implementation as a wrapper for this for now.
Signed-hostap: Jouni Malinen <j@w1.fi>
