strongswan: add fix for CVE-2021-45079

Full details of the CVE can be found at the following link:
https://www.strongswan.org/blog/2022/01/24/strongswan-vulnerability-(cve-2021-45079).html

Signed-off-by: Florian Eckert <fe@dev.tdt.de>

diff --git a/net/strongswan/patches/710-strongswan-5.5.0-5.9.4_eap_success.patch b/net/strongswan/patches/710-strongswan-5.5.0-5.9.4_eap_success.patch
new file mode 100644 (file)
index 0000000..4647d5b
--- /dev/null
+++ b/net/strongswan/patches/710-strongswan-5.5.0-5.9.4_eap_success.patch
@@ -0,0 +1,138 @@
+From 76968cdd6b79f6ae40d674554e902ced192fd33e Mon Sep 17 00:00:00 2001
+From: Tobias Brunner <tobias@strongswan.org>
+Date: Tue, 14 Dec 2021 10:51:35 +0100
+Subject: [PATCH] eap-authenticator: Enforce failure if MSK generation fails
+
+Without this, the authentication succeeded if the server sent an early
+EAP-Success message for mutual, key-generating EAP methods like EAP-TLS,
+which may be used in EAP-only scenarios but would complete without server
+or client authentication.  For clients configured for such EAP-only
+scenarios, a rogue server could capture traffic after the tunnel is
+established or even access hosts behind the client.  For non-mutual EAP
+methods, public key server authentication has been enforced for a while.
+
+A server previously could also crash a client by sending an EAP-Success
+immediately without initiating an actual EAP method.
+
+Fixes: 0706c39cda52 ("added support for EAP methods not establishing an MSK")
+Fixes: CVE-2021-45079
+---
+ src/libcharon/plugins/eap_gtc/eap_gtc.c       |  2 +-
+ src/libcharon/plugins/eap_md5/eap_md5.c       |  2 +-
+ src/libcharon/plugins/eap_radius/eap_radius.c |  4 ++-
+ src/libcharon/sa/eap/eap_method.h             |  8 ++++-
+ .../ikev2/authenticators/eap_authenticator.c  | 32 ++++++++++++++++---
+ 5 files changed, 40 insertions(+), 8 deletions(-)
+
+--- a/src/libcharon/plugins/eap_gtc/eap_gtc.c
++++ b/src/libcharon/plugins/eap_gtc/eap_gtc.c
+@@ -195,7 +195,7 @@ METHOD(eap_method_t, get_type, eap_type_
+ METHOD(eap_method_t, get_msk, status_t,
+       private_eap_gtc_t *this, chunk_t *msk)
+ {
+-      return FAILED;
++      return NOT_SUPPORTED;
+ }
+ 
+ METHOD(eap_method_t, get_identifier, uint8_t,
+--- a/src/libcharon/plugins/eap_md5/eap_md5.c
++++ b/src/libcharon/plugins/eap_md5/eap_md5.c
+@@ -213,7 +213,7 @@ METHOD(eap_method_t, get_type, eap_type_
+ METHOD(eap_method_t, get_msk, status_t,
+       private_eap_md5_t *this, chunk_t *msk)
+ {
+-      return FAILED;
++      return NOT_SUPPORTED;
+ }
+ 
+ METHOD(eap_method_t, is_mutual, bool,
+--- a/src/libcharon/plugins/eap_radius/eap_radius.c
++++ b/src/libcharon/plugins/eap_radius/eap_radius.c
+@@ -733,7 +733,9 @@ METHOD(eap_method_t, get_msk, status_t,
+               *out = msk;
+               return SUCCESS;
+       }
+-      return FAILED;
++      /* we assume the selected method did not establish an MSK, if it failed
++       * to establish one, process() would have failed */
++      return NOT_SUPPORTED;
+ }
+ 
+ METHOD(eap_method_t, get_identifier, uint8_t,
+--- a/src/libcharon/sa/eap/eap_method.h
++++ b/src/libcharon/sa/eap/eap_method.h
+@@ -114,10 +114,16 @@ struct eap_method_t {
+        * Not all EAP methods establish a shared secret. For implementations of
+        * the EAP-Identity method, get_msk() returns the received identity.
+        *
++       * @note Returning NOT_SUPPORTED is important for implementations of EAP
++       * methods that don't establish an MSK.  In particular as client because
++       * key-generating EAP methods MUST fail to process EAP-Success messages if
++       * no MSK is established.
++       *
+        * @param msk                   chunk receiving internal stored MSK
+        * @return
+-       *                                              - SUCCESS, or
++       *                                              - SUCCESS, if MSK is established
+        *                                              - FAILED, if MSK not established (yet)
++       *                                              - NOT_SUPPORTED, for non-MSK-establishing methods
+        */
+       status_t (*get_msk) (eap_method_t *this, chunk_t *msk);
+ 
+--- a/src/libcharon/sa/ikev2/authenticators/eap_authenticator.c
++++ b/src/libcharon/sa/ikev2/authenticators/eap_authenticator.c
+@@ -305,9 +305,17 @@ static eap_payload_t* server_process_eap
+                               this->method->destroy(this->method);
+                               return server_initiate_eap(this, FALSE);
+                       }
+-                      if (this->method->get_msk(this->method, &this->msk) == SUCCESS)
++                      switch (this->method->get_msk(this->method, &this->msk))
+                       {
+-                              this->msk = chunk_clone(this->msk);
++                              case SUCCESS:
++                                      this->msk = chunk_clone(this->msk);
++                                      break;
++                              case NOT_SUPPORTED:
++                                      break;
++                              case FAILED:
++                              default:
++                                      DBG1(DBG_IKE, "failed to establish MSK");
++                                      goto failure;
+                       }
+                       if (vendor)
+                       {
+@@ -326,6 +334,7 @@ static eap_payload_t* server_process_eap
+                       return eap_payload_create_code(EAP_SUCCESS, in->get_identifier(in));
+               case FAILED:
+               default:
++failure:
+                       /* type might have changed for virtual methods */
+                       type = this->method->get_type(this->method, &vendor);
+                       if (vendor)
+@@ -661,9 +670,24 @@ METHOD(authenticator_t, process_client,
+                               uint32_t vendor;
+                               auth_cfg_t *cfg;
+ 
+-                              if (this->method->get_msk(this->method, &this->msk) == SUCCESS)
++                              if (!this->method)
+                               {
+-                                      this->msk = chunk_clone(this->msk);
++                                      DBG1(DBG_IKE, "received unexpected %N",
++                                               eap_code_names, eap_payload->get_code(eap_payload));
++                                      return FAILED;
++                              }
++                              switch (this->method->get_msk(this->method, &this->msk))
++                              {
++                                      case SUCCESS:
++                                              this->msk = chunk_clone(this->msk);
++                                              break;
++                                      case NOT_SUPPORTED:
++                                              break;
++                                      case FAILED:
++                                      default:
++                                              DBG1(DBG_IKE, "received %N but failed to establish MSK",
++                                                       eap_code_names, eap_payload->get_code(eap_payload));
++                                              return FAILED;
+                               }
+                               type = this->method->get_type(this->method, &vendor);
+                               if (vendor)