http1: configurable max number of live tx per flow

Ticket: #5921

Co-authored-by: Jason Ish <jason.ish@oisf.net>

configure.ac

@@ -1620,6 +1620,7 @@
         AC_CHECK_LIB([htp], [htp_config_set_lzma_layers],AC_DEFINE_UNQUOTED([HAVE_HTP_CONFIG_SET_LZMA_LAYERS],[1],[Found htp_config_set_lzma_layers function in libhtp]) ,,[-lhtp])
         AC_CHECK_LIB([htp], [htp_config_set_compression_bomb_limit],AC_DEFINE_UNQUOTED([HAVE_HTP_CONFIG_SET_COMPRESSION_BOMB_LIMIT],[1],[Found htp_config_set_compression_bomb_limit function in libhtp]) ,,[-lhtp])
         AC_CHECK_LIB([htp], [htp_config_set_compression_time_limit],AC_DEFINE_UNQUOTED([HAVE_HTP_CONFIG_SET_COMPRESSION_TIME_LIMIT],[1],[Found htp_config_set_compression_time_limit function in libhtp]) ,,[-lhtp])
+        AC_CHECK_LIB([htp], [htp_config_set_max_tx],AC_DEFINE_UNQUOTED([HAVE_HTP_CONFIG_SET_MAX_TX],[1],[Found htp_config_set_max_tx function in libhtp]) ,,[-lhtp])
     ])
 
     if test "x$enable_non_bundled_htp" = "xno"; then
@@ -1644,6 +1645,7 @@
             AC_DEFINE_UNQUOTED([HAVE_HTP_CONFIG_SET_LZMA_LAYERS],[1],[Assuming htp_config_set_lzma_layers function in bundled libhtp])
             AC_DEFINE_UNQUOTED([HAVE_HTP_CONFIG_SET_COMPRESSION_BOMB_LIMIT],[1],[Assuming htp_config_set_compression_bomb_limit function in bundled libhtp])
             AC_DEFINE_UNQUOTED([HAVE_HTP_CONFIG_SET_COMPRESSION_TIME_LIMIT],[1],[Assuming htp_config_set_compression_time_limit function in bundled libhtp])
+            AC_DEFINE_UNQUOTED([HAVE_HTP_CONFIG_SET_MAX_TX],[1],[Assuming htp_config_set_max_tx function in bundled libhtp])
         else
             echo
             echo "  ERROR: Libhtp is not bundled. Get libhtp by doing:"

doc/userguide/configuration/suricata-yaml.rst

@@ -1748,7 +1748,7 @@ incompatible with ``decode-mime``. If both are enabled,
 Maximum transactions
 ~~~~~~~~~~~~~~~~~~~~
 
-MQTT, FTP, PostgreSQL, SMB, DCERPC and NFS have each a `max-tx` parameter that can be customized.
+MQTT, FTP, PostgreSQL, SMB, DCERPC, HTTP1 and NFS have each a `max-tx` parameter that can be customized.
 `max-tx` refers to the maximum number of live transactions for each flow.
 An app-layer event `protocol.too_many_transactions` is triggered when this value is reached.
 The point of this parameter is to find a balance between the completeness of analysis

src/app-layer-htp.c

@@ -2517,6 +2517,10 @@ static void HTPConfigSetDefaultsPhase1(HTPCfgRec *cfg_prec)
 #endif
 #ifdef HAVE_HTP_CONFIG_SET_COMPRESSION_TIME_LIMIT
     htp_config_set_compression_time_limit(cfg_prec->cfg, HTP_CONFIG_DEFAULT_COMPRESSION_TIME_LIMIT);
+#endif
+#ifdef HAVE_HTP_CONFIG_SET_MAX_TX
+#define HTP_CONFIG_DEFAULT_MAX_TX_LIMIT 512
+    htp_config_set_max_tx(cfg_prec->cfg, HTP_CONFIG_DEFAULT_MAX_TX_LIMIT);
 #endif
     /* libhtp <= 0.5.9 doesn't use soft limit, but it's impossible to set
      * only the hard limit. So we set both here to the (current) htp defaults.
@@ -2868,6 +2872,18 @@ static void HTPConfigParseParameters(HTPCfgRec *cfg_prec, ConfNode *s,
             }
             SCLogConfig("Setting HTTP decompression time limit to %" PRIu32 " usec", limit);
             htp_config_set_compression_time_limit(cfg_prec->cfg, (size_t)limit);
+#endif
+#ifdef HAVE_HTP_CONFIG_SET_MAX_TX
+        } else if (strcasecmp("max-tx", p->name) == 0) {
+            uint32_t limit = 0;
+            if (ParseSizeStringU32(p->val, &limit) < 0) {
+                FatalError("failed to parse 'max-tx' "
+                           "from conf file - %s.",
+                        p->val);
+            }
+            /* set default soft-limit with our new hard limit */
+            SCLogConfig("Setting HTTP max-tx limit to %" PRIu32 " bytes", limit);
+            htp_config_set_max_tx(cfg_prec->cfg, (size_t)limit);
 #endif
         } else if (strcasecmp("randomize-inspection-sizes", p->name) == 0) {
             if (!g_disable_randomness) {

suricata.yaml.in

@@ -1081,6 +1081,8 @@ app-layer:
            #compression-bomb-limit: 1mb
            # Maximum time spent decompressing a single transaction in usec
            #decompression-time-limit: 100000
+           # Maximum number of live transactions per flow
+           #max-tx: 512
 
          server-config: