make EIA and EEA algorithms configurable (#323)

this patch allows to configure the EIA and EEA algorithms
the UE uses and announces during attach. They can
be specified as a comma-separated list.

The patch also removes a dedicated NAS config class and uses
the default nas_args_t type for this. There was a full
duplication of members before.

The patch also converts nas_args_t and usim_args_t into a class
with a default constructor that initialize all booleans.

lib/include/srslte/common/interfaces_common.h

@@ -31,30 +31,8 @@
 #include "srslte/common/security.h"
 #include <string>
 
-
 namespace srslte {
 
-class srslte_nas_config_t
-{
-public:
-  srslte_nas_config_t(uint32_t lcid_ = 0, std::string apn_ = "", std::string apn_protocol_ = "", std::string user_ = "", std::string pass_ = "", bool force_imsi_attach_ = false)
-    :lcid(lcid_),
-     apn(apn_),
-     apn_protocol(apn_protocol_),
-     user(user_),
-     pass(pass_),
-     force_imsi_attach(force_imsi_attach_)
-    {}
-
-  uint32_t    lcid;
-  std::string apn;
-  std::string apn_protocol;
-  std::string user;
-  std::string pass;
-  bool        force_imsi_attach;
-};
-
-
 class srslte_gw_config_t
 {
 public:

srsue/hdr/upper/nas.h

@@ -39,13 +39,19 @@ using srslte::byte_buffer_t;
 
 namespace srsue {
 
-typedef struct {
+class nas_args_t
+{
+public:
+  nas_args_t() : force_imsi_attach(false) {}
+
   std::string apn_name;
   std::string apn_protocol;
   std::string apn_user;
   std::string apn_pass;
   bool        force_imsi_attach;
-} nas_args_t;
+  std::string eia;
+  std::string eea;
+};
 
 // EMM states (3GPP 24.302 v10.0.0)
 typedef enum {
@@ -62,9 +68,6 @@ static const char emm_state_text[EMM_STATE_N_ITEMS][100] = {"NULL",
                                                             "DEREGISTERED INITIATED",
                                                             "TRACKING AREA UPDATE INITIATED"};
 
-static const bool eia_caps[8] = {false, true, true, false, false, false, false, false};
-static const bool eea_caps[8] = {true,  true, true, false, false, false, false, false};
-
 class nas
   : public nas_interface_rrc,
     public nas_interface_ue,
@@ -72,11 +75,11 @@ class nas
 {
 public:
   nas();
-  void init(usim_interface_nas  *usim_,
-            rrc_interface_nas   *rrc_,
-            gw_interface_nas    *gw_,
-            srslte::log         *nas_log_,
-            srslte::srslte_nas_config_t cfg_);
+  void init(usim_interface_nas* usim_,
+            rrc_interface_nas*  rrc_,
+            gw_interface_nas*   gw_,
+            srslte::log*        nas_log_,
+            nas_args_t          args_);
   void stop();
 
   emm_state_t get_state();
@@ -105,7 +108,7 @@ private:
   usim_interface_nas *usim;
   gw_interface_nas *gw;
 
-  srslte::srslte_nas_config_t cfg;
+  nas_args_t cfg;
 
   emm_state_t state;
 
@@ -145,6 +148,8 @@ private:
   uint8_t transaction_id;
 
   // Security
+  bool    eia_caps[8];
+  bool    eea_caps[8];
   uint8_t k_nas_enc[32];
   uint8_t k_nas_int[32];
 
@@ -234,6 +239,20 @@ private:
     }
     return true;
   }
+
+  std::vector<uint8_t> split_string(const std::string input)
+  {
+    std::vector<uint8_t> list;
+    std::stringstream    ss(input);
+    while (ss.good()) {
+      std::string substr;
+      getline(ss, substr, ',');
+      if (not substr.empty()) {
+        list.push_back(atoi(substr.c_str()));
+      }
+    }
+    return list;
+  }
 };
 
 } // namespace srsue

srsue/hdr/upper/usim_base.h

@@ -40,7 +40,10 @@ typedef enum{
   auth_algo_xor,
 }auth_algo_t;
 
-typedef struct{
+class usim_args_t
+{
+public:
+  usim_args_t() : using_op(false) {}
   std::string mode;
   std::string algo;
   bool using_op;
@@ -51,7 +54,7 @@ typedef struct{
   std::string k;
   std::string pin;
   std::string reader;
-}usim_args_t;
+};
 
 class usim_base
     :public usim_interface_nas

srsue/src/main.cc

@@ -92,6 +92,8 @@ void parse_args(all_args_t* args, int argc, char* argv[])
     ("nas.user",              bpo::value<string>(&args->nas.apn_user)->default_value(""),  "Username for CHAP authentication")
     ("nas.pass",              bpo::value<string>(&args->nas.apn_pass)->default_value(""),  "Password for CHAP authentication")
     ("nas.force_imsi_attach", bpo::value<bool>(&args->nas.force_imsi_attach)->default_value(false),  "Whether to always perform an IMSI attach")
+    ("nas.eia",               bpo::value<string>(&args->nas.eia)->default_value("1,2"),  "List of integrity algorithms included in UE capabilities")
+    ("nas.eea",               bpo::value<string>(&args->nas.eea)->default_value("0,1,2"),  "List of ciphering algorithms included in UE capabilities")
 
     ("pcap.enable", bpo::value<bool>(&args->pcap.enable)->default_value(false), "Enable MAC packet captures for wireshark")
     ("pcap.filename", bpo::value<string>(&args->pcap.filename)->default_value("ue.pcap"), "MAC layer capture filename")

srsue/src/ue.cc

@@ -116,7 +116,6 @@ bool ue::init(all_args_t *args_) {
     phy_log.push_back(NULL);
   }
 
-  
   mac_log.set_level(level(args->log.mac_level));
   rlc_log.set_level(level(args->log.rlc_level));
   pdcp_log.set_level(level(args->log.pdcp_level));
@@ -242,9 +241,7 @@ bool ue::init(all_args_t *args_) {
   mac.init(&phy, &rlc, &rrc, &mac_log);
   rlc.init(&pdcp, &rrc, this, &rlc_log, &mac, 0 /* RB_ID_SRB0 */);
   pdcp.init(&rlc, &rrc, &gw, &pdcp_log, 0 /* RB_ID_SRB0 */, SECURITY_DIRECTION_UPLINK);
-
-  srslte_nas_config_t nas_cfg(1, args->nas.apn_name, args->nas.apn_protocol, args->nas.apn_user, args->nas.apn_pass, args->nas.force_imsi_attach); /* RB_ID_SRB1 */
-  nas.init(usim, &rrc, &gw, &nas_log, nas_cfg);
+  nas.init(usim, &rrc, &gw, &nas_log, args->nas);
   gw.init(&pdcp, &nas, &gw_log, 3 /* RB_ID_DRB1 */);
   gw.set_netmask(args->expert.ip_netmask);
   gw.set_tundevname(args->expert.ip_devname);

srsue/src/upper/nas.cc

@@ -55,13 +55,12 @@ nas::nas()
   plmn_is_selected = false;
   chap_id = 0;
   memset(ipv6_if_id, 0, sizeof(ipv6_if_id));
+  bzero(eia_caps, sizeof(eia_caps));
+  bzero(eea_caps, sizeof(eea_caps));
 }
 
-void nas::init(usim_interface_nas *usim_,
-               rrc_interface_nas *rrc_,
-               gw_interface_nas *gw_,
-               srslte::log *nas_log_,
-               srslte::srslte_nas_config_t cfg_)
+void nas::init(
+    usim_interface_nas* usim_, rrc_interface_nas* rrc_, gw_interface_nas* gw_, srslte::log* nas_log_, nas_args_t cfg_)
 {
   pool = byte_buffer_pool::get_instance();
   usim = usim_;
@@ -78,6 +77,33 @@ void nas::init(usim_interface_nas *usim_,
     srslte::mcc_to_bytes(mcc, &home_plmn.mcc[0]);
     srslte::mnc_to_bytes(mnc, home_plmn.mnc);
   }
+
+  // parse and sanity check EIA list
+  std::vector<uint8_t> cap_list = split_string(cfg_.eia);
+  if (cap_list.empty()) {
+    nas_log->error("Empty EIA list. Select at least one EIA algorithm.\n");
+  }
+  for (std::vector<uint8_t>::const_iterator it = cap_list.begin(); it != cap_list.end(); ++it) {
+    if (*it != 0 && *it < 3) {
+      eia_caps[*it] = true;
+    } else {
+      nas_log->error("EIA%d is not a valid EIA algorithm.\n", *it);
+    }
+  }
+
+  // parse and sanity check EEA list
+  cap_list = split_string(cfg_.eea);
+  if (cap_list.empty()) {
+    nas_log->error("Empty EEA list. Select at least one EEA algorithm.\n");
+  }
+  for (std::vector<uint8_t>::const_iterator it = cap_list.begin(); it != cap_list.end(); ++it) {
+    if (*it < 3) {
+      eea_caps[*it] = true;
+    } else {
+      nas_log->error("EEA%d is not a valid EEA algorithm.\n", *it);
+    }
+  }
+
   cfg     = cfg_;
 
   if((read_ctxt_file(&ctxt))) {
@@ -1297,7 +1323,7 @@ void nas::gen_pdn_connectivity_request(LIBLTE_BYTE_MSG_STRUCT *msg) {
   }
 
   // Set the optional flags
-  if (cfg.apn == "") {
+  if (cfg.apn_name == "") {
     pdn_con_req.esm_info_transfer_flag_present = false;
   } else {
     // request ESM info transfer is APN is specified
@@ -1573,29 +1599,24 @@ void nas::send_esm_information_response(const uint8 proc_transaction_id) {
   esm_info_resp.proc_transaction_id = proc_transaction_id;
   esm_info_resp.eps_bearer_id = 0; // respone shall always have no bearer assigned
 
-  if (cfg.apn == "") {
+  if (cfg.apn_name == "") {
     esm_info_resp.apn_present = false;
   } else {
-    nas_log->debug("Including APN %s in ESM info response\n", cfg.apn.c_str());
+    nas_log->debug("Including APN %s in ESM info response\n", cfg.apn_name.c_str());
     esm_info_resp.apn_present = true;
-    int len = std::min((int)cfg.apn.length(), LIBLTE_STRING_LEN-1);
-    strncpy(esm_info_resp.apn.apn, cfg.apn.c_str(), len);
+    int len                   = std::min((int)cfg.apn_name.length(), LIBLTE_STRING_LEN - 1);
+    strncpy(esm_info_resp.apn.apn, cfg.apn_name.c_str(), len);
     esm_info_resp.apn.apn[len] = '\0';
   }
 
+  if (cfg.apn_user != "" && cfg.apn_user.length() < LIBLTE_STRING_LEN && cfg.apn_pass != "" &&
+      cfg.apn_pass.length() < LIBLTE_STRING_LEN) {
 
-  if (cfg.user != "" && cfg.user.length() < LIBLTE_STRING_LEN &&
-      cfg.pass != "" && cfg.pass.length() < LIBLTE_STRING_LEN) {
-
-    nas_log->debug("Including CHAP authentication for user %s in ESM info response\n", cfg.user.c_str());
+    nas_log->debug("Including CHAP authentication for user %s in ESM info response\n", cfg.apn_user.c_str());
 
     // Generate CHAP challenge
-    uint16_t len = 1 /* CHAP code */ +
-                   1 /* ID */ +
-                   2 /* complete length */ +
-                   1 /* data value size */ +
-                   16 /* data value */ +
-                   cfg.user.length();
+    uint16_t len = 1 /* CHAP code */ + 1 /* ID */ + 2 /* complete length */ + 1 /* data value size */ +
+                   16 /* data value */ + cfg.apn_user.length();
 
     uint8_t challenge[len];
     bzero(challenge, len*sizeof(uint8_t));
@@ -1611,8 +1632,8 @@ void nas::send_esm_information_response(const uint8 proc_transaction_id) {
     }
 
     // add user as name field
-    for (size_t i = 0; i < cfg.user.length(); i++) {
-      const char *name = cfg.user.c_str();
+    for (size_t i = 0; i < cfg.apn_user.length(); i++) {
+      const char* name  = cfg.apn_user.c_str();
       challenge[21 + i] = name[i];
     }
 
@@ -1626,32 +1647,30 @@ void nas::send_esm_information_response(const uint8 proc_transaction_id) {
     response[4] = 16;
 
     // Generate response value
-    uint16_t resp_val_len = 16 /* MD5 len */ +
-                            1 /* ID */ +
-                            cfg.pass.length();
+    uint16_t resp_val_len = 16 /* MD5 len */ + 1 /* ID */ + cfg.apn_pass.length();
     uint8_t resp_val[resp_val_len];
     resp_val[0] = chap_id;
 
     // add secret
-    for (size_t i = 0; i < cfg.pass.length(); i++) {
-      const char* pass = cfg.pass.c_str();
+    for (size_t i = 0; i < cfg.apn_pass.length(); i++) {
+      const char* pass = cfg.apn_pass.c_str();
       resp_val[1 + i] = pass[i];
     }
 
     // copy original challenge behind secret
     uint8_t *chal_val = &challenge[5];
-    memcpy(&resp_val[1+cfg.pass.length()], chal_val, 16);
+    memcpy(&resp_val[1 + cfg.apn_pass.length()], chal_val, 16);
 
     // Compute MD5 of resp_val and add to response
     security_md5(resp_val, resp_val_len, &response[5]);
 
     // add user as name field again
-    for (size_t i = 0; i < cfg.user.length(); i++) {
-      const char *name = cfg.user.c_str();
+    for (size_t i = 0; i < cfg.apn_user.length(); i++) {
+      const char* name = cfg.apn_user.c_str();
       response[21 + i] = name[i];
     }
 
-    // Add challenge and resposne to ESM info response
+    // Add challenge and response to ESM info response
     esm_info_resp.protocol_cnfg_opts_present = true;
     esm_info_resp.protocol_cnfg_opts.opt[0].id = LIBLTE_MME_CONFIGURATION_PROTOCOL_OPTIONS_CHAP;
     memcpy(esm_info_resp.protocol_cnfg_opts.opt[0].contents, challenge, sizeof(challenge));

srsue/test/upper/nas_test.cc

@@ -170,8 +170,9 @@ int security_command_test()
   usim.init(&args, &usim_log);
 
   srsue::nas nas;
-  srslte_nas_config_t cfg;
-  ZERO_OBJECT(cfg);
+  nas_args_t cfg;
+  cfg.eia = "1,2";
+  cfg.eea = "0,1,2";
   nas.init(&usim, &rrc_dummy, &gw, &nas_log, cfg);
 
   // push auth request PDU to NAS to generate security context
@@ -230,10 +231,9 @@ int mme_attach_request_test()
   args.op = "63BFA50EE6523365FF14C1F45F88737D";
   usim.init(&args, &usim_log);
 
-  srslte_nas_config_t nas_cfg;
-  ZERO_OBJECT(nas_cfg);
+  nas_args_t nas_cfg;
   nas_cfg.force_imsi_attach = true;
-  nas_cfg.apn = "test123";
+  nas_cfg.apn_name          = "test123";
   srsue::nas nas;
   srsue::gw gw;
 
@@ -302,11 +302,10 @@ int esm_info_request_test()
   pool = byte_buffer_pool::get_instance();
 
   srsue::nas nas;
-  srslte_nas_config_t cfg;
-  ZERO_OBJECT(cfg);
-  cfg.apn = "srslte";
-  cfg.user = "srsuser";
-  cfg.pass = "srspass";
+  nas_args_t cfg;
+  cfg.apn_name          = "srslte";
+  cfg.apn_user          = "srsuser";
+  cfg.apn_pass          = "srspass";
   cfg.force_imsi_attach = true;
   nas.init(&usim, &rrc_dummy, &gw, &nas_log, cfg);
 

srsue/ue.conf.example

@@ -124,6 +124,10 @@ imei = 353490069873319
 # user:              Username for CHAP authentication
 # pass:              Password for CHAP authentication
 # force_imsi_attach: Whether to always perform an IMSI attach
+# eia:               List of integrity algorithms included in UE capabilities
+#                      Supported: 1 - Snow3G, 2 - AES
+# eea:               List of ciphering algorithms included in UE capabilities
+#                      Supported: 0 - NULL, 1 - Snow3G, 2 - AES
 #####################################################################
 [nas]
 #apn = internetinternet
@@ -131,6 +135,8 @@ imei = 353490069873319
 #user = srsuser
 #pass = srspass
 #force_imsi_attach = false
+#eia = 1,2
+#eea = 0,1,2
 
 [gui]
 enable = false