OpenSSL: unsafe legacy renegotiation can be allowed/disallowed by configuration

Resolves: #2077973
Signed-off-by: Davide Caratti <dcaratti@redhat.com>
This commit is contained in:
Davide Caratti 2022-05-13 16:16:03 +02:00
parent 8973e76f82
commit 62ab4bd374
3 changed files with 217 additions and 1 deletions

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@ -0,0 +1,103 @@
From 566ce69a8d0e64093309cbde80235aa522fbf84e Mon Sep 17 00:00:00 2001
Message-Id: <566ce69a8d0e64093309cbde80235aa522fbf84e.1652450572.git.davide.caratti@gmail.com>
From: Jouni Malinen <quic_jouni@quicinc.com>
Date: Thu, 5 May 2022 00:07:44 +0300
Subject: [PATCH] EAP peer: Workaround for servers that do not support safe TLS
renegotiation
The TLS protocol design for renegotiation was identified to have a
significant security flaw in 2009 and an extension to secure this design
was published in 2010 (RFC 5746). However, some old RADIUS
authentication servers without support for this are still used commonly.
This is obviously not good from the security view point, but since there
are cases where the user of a network service has no realistic means for
getting the authentication server upgraded, TLS handshake may still need
to be allowed to be able to use the network.
OpenSSL 3.0 disabled the client side workaround by default and this
resulted in issues connection to some networks with insecure
authentication servers. With OpenSSL 3.0, the client is now enforcing
security by refusing to authenticate with such servers. The pre-3.0
behavior of ignoring this issue and leaving security to the server can
now be enabled with a new phase1 parameter allow_unsafe_renegotiation=1.
This should be used only when having to connect to a network that has an
insecure authentication server that cannot be upgraded.
The old (pre-2010) TLS renegotiation mechanism might open security
vulnerabilities if the authentication server were to allow TLS
renegotiation to be initiated. While this is unlikely to cause real
issues with EAP-TLS, there might be cases where use of PEAP or TTLS with
an authentication server that does not support RFC 5746 might result in
a security vulnerability.
Signed-off-by: Jouni Malinen <quic_jouni@quicinc.com>
---
src/crypto/tls.h | 1 +
src/crypto/tls_openssl.c | 5 +++++
src/eap_peer/eap_tls_common.c | 4 ++++
wpa_supplicant/wpa_supplicant.conf | 5 +++++
4 files changed, 15 insertions(+)
diff --git a/src/crypto/tls.h b/src/crypto/tls.h
index ccaac94c9..7ea32ee4a 100644
--- a/src/crypto/tls.h
+++ b/src/crypto/tls.h
@@ -112,6 +112,7 @@ struct tls_config {
#define TLS_CONN_ENABLE_TLSv1_1 BIT(15)
#define TLS_CONN_ENABLE_TLSv1_2 BIT(16)
#define TLS_CONN_TEAP_ANON_DH BIT(17)
+#define TLS_CONN_ALLOW_UNSAFE_RENEGOTIATION BIT(18)
/**
* struct tls_connection_params - Parameters for TLS connection
diff --git a/src/crypto/tls_openssl.c b/src/crypto/tls_openssl.c
index 388c6b0f4..0d23f44ad 100644
--- a/src/crypto/tls_openssl.c
+++ b/src/crypto/tls_openssl.c
@@ -3081,6 +3081,11 @@ static int tls_set_conn_flags(struct tls_connection *conn, unsigned int flags,
SSL_clear_options(ssl, SSL_OP_NO_TICKET);
#endif /* SSL_OP_NO_TICKET */
+#ifdef SSL_OP_LEGACY_SERVER_CONNECT
+ if (flags & TLS_CONN_ALLOW_UNSAFE_RENEGOTIATION)
+ SSL_set_options(ssl, SSL_OP_LEGACY_SERVER_CONNECT);
+#endif /* SSL_OP_LEGACY_SERVER_CONNECT */
+
#ifdef SSL_OP_NO_TLSv1
if (flags & TLS_CONN_DISABLE_TLSv1_0)
SSL_set_options(ssl, SSL_OP_NO_TLSv1);
diff --git a/src/eap_peer/eap_tls_common.c b/src/eap_peer/eap_tls_common.c
index 06c9b211e..6193b4bdb 100644
--- a/src/eap_peer/eap_tls_common.c
+++ b/src/eap_peer/eap_tls_common.c
@@ -102,6 +102,10 @@ static void eap_tls_params_flags(struct tls_connection_params *params,
params->flags |= TLS_CONN_SUITEB_NO_ECDH;
if (os_strstr(txt, "tls_suiteb_no_ecdh=0"))
params->flags &= ~TLS_CONN_SUITEB_NO_ECDH;
+ if (os_strstr(txt, "allow_unsafe_renegotiation=1"))
+ params->flags |= TLS_CONN_ALLOW_UNSAFE_RENEGOTIATION;
+ if (os_strstr(txt, "allow_unsafe_renegotiation=0"))
+ params->flags &= ~TLS_CONN_ALLOW_UNSAFE_RENEGOTIATION;
}
diff --git a/wpa_supplicant/wpa_supplicant.conf b/wpa_supplicant/wpa_supplicant.conf
index a1dc769c9..b5304a77e 100644
--- a/wpa_supplicant/wpa_supplicant.conf
+++ b/wpa_supplicant/wpa_supplicant.conf
@@ -1370,6 +1370,11 @@ fast_reauth=1
# tls_suiteb=0 - do not apply Suite B 192-bit constraints on TLS (default)
# tls_suiteb=1 - apply Suite B 192-bit constraints on TLS; this is used in
# particular when using Suite B with RSA keys of >= 3K (3072) bits
+# allow_unsafe_renegotiation=1 - allow connection with a TLS server that does
+# not support safe renegotiation (RFC 5746); please note that this
+# workaround should be only when having to authenticate with an old
+# authentication server that cannot be updated to use secure TLS
+# implementation.
#
# Following certificate/private key fields are used in inner Phase2
# authentication when using EAP-TTLS or EAP-PEAP.
--
2.35.1

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@ -0,0 +1,106 @@
From a561d12d24c2c8bb0f825d4a3a55a5e47e845853 Mon Sep 17 00:00:00 2001
Message-Id: <a561d12d24c2c8bb0f825d4a3a55a5e47e845853.1652450863.git.davide.caratti@gmail.com>
From: Jouni Malinen <quic_jouni@quicinc.com>
Date: Wed, 4 May 2022 23:55:38 +0300
Subject: [PATCH] EAP peer status notification for server not supporting RFC
5746
Add a notification message to indicate reason for TLS handshake failure
due to the server not supporting safe renegotiation (RFC 5746).
Signed-off-by: Jouni Malinen <quic_jouni@quicinc.com>
---
src/ap/authsrv.c | 3 +++
src/crypto/tls.h | 3 ++-
src/crypto/tls_openssl.c | 15 +++++++++++++--
src/eap_peer/eap.c | 5 +++++
4 files changed, 23 insertions(+), 3 deletions(-)
diff --git a/src/ap/authsrv.c b/src/ap/authsrv.c
index 516c1da74..fd9c96fad 100644
--- a/src/ap/authsrv.c
+++ b/src/ap/authsrv.c
@@ -169,6 +169,9 @@ static void authsrv_tls_event(void *ctx, enum tls_event ev,
wpa_printf(MSG_DEBUG, "authsrv: remote TLS alert: %s",
data->alert.description);
break;
+ case TLS_UNSAFE_RENEGOTIATION_DISABLED:
+ /* Not applicable to TLS server */
+ break;
}
}
#endif /* EAP_TLS_FUNCS */
diff --git a/src/crypto/tls.h b/src/crypto/tls.h
index 7ea32ee4a..7a2ee32df 100644
--- a/src/crypto/tls.h
+++ b/src/crypto/tls.h
@@ -22,7 +22,8 @@ enum tls_event {
TLS_CERT_CHAIN_SUCCESS,
TLS_CERT_CHAIN_FAILURE,
TLS_PEER_CERTIFICATE,
- TLS_ALERT
+ TLS_ALERT,
+ TLS_UNSAFE_RENEGOTIATION_DISABLED,
};
/*
diff --git a/src/crypto/tls_openssl.c b/src/crypto/tls_openssl.c
index 0d23f44ad..912471ba2 100644
--- a/src/crypto/tls_openssl.c
+++ b/src/crypto/tls_openssl.c
@@ -4443,6 +4443,7 @@ int tls_connection_get_eap_fast_key(void *tls_ctx, struct tls_connection *conn,
static struct wpabuf *
openssl_handshake(struct tls_connection *conn, const struct wpabuf *in_data)
{
+ struct tls_context *context = conn->context;
int res;
struct wpabuf *out_data;
@@ -4472,7 +4473,19 @@ openssl_handshake(struct tls_connection *conn, const struct wpabuf *in_data)
wpa_printf(MSG_DEBUG, "SSL: SSL_connect - want to "
"write");
else {
+ unsigned long error = ERR_peek_last_error();
+
tls_show_errors(MSG_INFO, __func__, "SSL_connect");
+
+ if (context->event_cb &&
+ ERR_GET_LIB(error) == ERR_LIB_SSL &&
+ ERR_GET_REASON(error) ==
+ SSL_R_UNSAFE_LEGACY_RENEGOTIATION_DISABLED) {
+ context->event_cb(
+ context->cb_ctx,
+ TLS_UNSAFE_RENEGOTIATION_DISABLED,
+ NULL);
+ }
conn->failed++;
if (!conn->server && !conn->client_hello_generated) {
/* The server would not understand TLS Alert
@@ -4495,8 +4508,6 @@ openssl_handshake(struct tls_connection *conn, const struct wpabuf *in_data)
if ((conn->flags & TLS_CONN_SUITEB) && !conn->server &&
os_strncmp(SSL_get_cipher(conn->ssl), "DHE-", 4) == 0 &&
conn->server_dh_prime_len < 3072) {
- struct tls_context *context = conn->context;
-
/*
* This should not be reached since earlier cert_cb should have
* terminated the handshake. Keep this check here for extra
diff --git a/src/eap_peer/eap.c b/src/eap_peer/eap.c
index 429b20d3a..729388f4f 100644
--- a/src/eap_peer/eap.c
+++ b/src/eap_peer/eap.c
@@ -2172,6 +2172,11 @@ static void eap_peer_sm_tls_event(void *ctx, enum tls_event ev,
eap_notify_status(sm, "remote TLS alert",
data->alert.description);
break;
+ case TLS_UNSAFE_RENEGOTIATION_DISABLED:
+ wpa_printf(MSG_INFO,
+ "TLS handshake failed due to the server not supporting safe renegotiation (RFC 5746); phase1 parameter allow_unsafe_renegotiation=1 can be used to work around this");
+ eap_notify_status(sm, "unsafe server renegotiation", "failure");
+ break;
}
os_free(hash_hex);
--
2.35.1

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@ -9,7 +9,7 @@ Summary: WPA/WPA2/IEEE 802.1X Supplicant
Name: wpa_supplicant
Epoch: 1
Version: 2.10
Release: 3%{?dist}
Release: 4%{?dist}
License: BSD
Source0: http://w1.fi/releases/%{name}-%{version}.tar.gz
Source1: wpa_supplicant.conf
@ -31,6 +31,9 @@ Patch3: wpa_supplicant-quiet-scan-results-message.patch
Patch4: wpa_supplicant-gui-qt4.patch
# backport fix for bz2063730
Patch5: 0001-D-Bus-Add-wep_disabled-capability.patch
# backport fix for bz2077973
Patch6: 0001-EAP-peer-Workaround-for-servers-that-do-not-support-.patch
Patch7: 0001-EAP-peer-status-notification-for-server-not-supporti.patch
URL: http://w1.fi/wpa_supplicant/
@ -191,6 +194,10 @@ chmod -R 0644 wpa_supplicant/examples/*.py
%changelog
* Fri May 13 2022 Davide Caratti <dcaratti@redhat.com> - 1:2.10-4
- Explicitly allow/disallow unsafe legacy renegotiation on configuration base.
Resolves: rhbz#2077973
* Fri Apr 22 2022 Davide Caratti <dcaratti@redhat.com> - 1:2.10-3
- Expose 'wep_disabled' capability via D-Bus. Resolves: rhbz#2063730