detect/firewall: policy for substates

For the most part hard coded for HTTP/2 for now.

src/detect-parse.c

@@ -4017,6 +4017,49 @@ static int DoParsePolicy(const char *policy_name, struct DetectFirewallPolicy *p
     return 1;
 }
 
+static int DoParseAppSubStatePolicy(const char *prefix, const AppProto app_proto,
+        const uint8_t sub_state, const char *sub_state_name, const uint8_t state,
+        const char *hookname, const uint8_t complete_state, const int direction,
+        struct DetectFirewallPolicies *fw_policies, struct DetectFirewallAppPolicy *app_fw_policies)
+{
+    char policy_name[256];
+    BUG_ON(sub_state_name == NULL);
+    BUG_ON(hookname == NULL);
+
+    char *nname = SCStrdup(hookname);
+    if (nname == NULL)
+        return -1;
+    for (int i = 0; nname[i] != '\0'; i++) {
+        if (nname[i] == '_')
+            nname[i] = '-';
+    }
+
+    const char *app_name = AppProtoToString(app_proto);
+    int r = snprintf(policy_name, sizeof(policy_name), "%s.%s.%s.%s", prefix, app_name,
+            sub_state_name, nname);
+    SCLogDebug("policy_name %s", policy_name);
+    SCFree(nname);
+    if (r < 0 || (size_t)r >= sizeof(policy_name)) {
+        FatalError("internal error: failed to assemble firewall policy config string");
+    }
+
+    struct DetectFirewallPolicy *pol;
+    if (direction == STREAM_TOSERVER)
+        pol = &fw_policies->http2_substates[sub_state - 1].ts[state];
+    else
+        pol = &fw_policies->http2_substates[sub_state - 1].tc[state];
+
+    r = DoParsePolicy(policy_name, pol);
+    /* for policies with an alert action, create a policy sig */
+    if (r == 1 && pol->action & ACTION_ALERT) {
+        SCLogDebug("adding policy signature");
+        return AddAppPolicySignature(fw_policies->policy_signatures, direction, app_proto, app_name,
+                state, hookname, pol);
+    }
+    SCLogDebug("r %d", r);
+    return r;
+}
+
 static int DoParseAppPolicy(const char *prefix, const AppProto app_proto, const char *hookname,
         const uint8_t state, const uint8_t complete_state, const int direction,
         struct DetectFirewallPolicies *fw_policies, struct DetectFirewallAppPolicy *app_fw_policies)
@@ -4122,6 +4165,17 @@ int DetectFirewallInitDefaultPolicies(DetectEngineCtx *de_ctx)
             app_fw_policies[a].tc[i].action_scope = ACTION_SCOPE_FLOW;
         }
     }
+
+    /* TODO hard coded for HTTP/2 for now */
+    for (int s = 0; s < 2; s++) {
+        for (int i = 0; i < 48; i++) {
+            fw_policies->http2_substates[s].ts[i].action = ACTION_DROP;
+            fw_policies->http2_substates[s].ts[i].action_scope = ACTION_SCOPE_FLOW;
+            fw_policies->http2_substates[s].tc[i].action = ACTION_DROP;
+            fw_policies->http2_substates[s].tc[i].action_scope = ACTION_SCOPE_FLOW;
+        }
+    }
+
     de_ctx->fw_policies = fw_policies;
     return 0;
 
@@ -4187,8 +4241,50 @@ int DetectFirewallLoadDefaultPolicies(DetectEngineCtx *de_ctx)
         if (!AppProtoIsValid(a))
             continue;
 
+        if (AppLayerParserSupportsSubStates(a)) {
+            uint8_t max_sub_state = AppLayerParserGetMaxSubState(a);
+            SCLogDebug("%s: max sub state for %u is %u", AppProtoToString(a), a, max_sub_state);
+            for (uint8_t s = 1; s <= max_sub_state; s++) {
+                SCLogDebug("%s: checking sub state %u", AppProtoToString(a), s);
+
+                const char *sub_state_name = AppLayerParserGetSubStateName(a, s);
+                if (sub_state_name == NULL)
+                    continue;
+
+                // iterate the states belonging to the sub state
+                const uint8_t max_state = AppLayerParserGetSubStateCompletion(
+                        a, s); // TODO allow different completion per direction?
+                /* to_server */
+                for (uint8_t state = 0; state <= max_state; state++) {
+                    SCLogDebug("protocol %s: sub state:%s state:%u", AppProtoToString(a),
+                            sub_state_name, state);
+                    const char *state_name =
+                            AppLayerParserGetSubStateProgressName(a, s, state, STREAM_TOSERVER);
+                    BUG_ON(state_name == NULL);
+                    SCLogDebug("protocol %s: sub state:%s state:%s", AppProtoToString(a),
+                            sub_state_name, state_name);
+                    if (DoParseAppSubStatePolicy(prefix, a, s, sub_state_name, state, state_name,
+                                max_state, STREAM_TOSERVER, fw_policies, app_fw_policies) < 0)
+                        return -1;
+                }
+                /* to_client */
+                for (uint8_t state = 0; state <= max_state; state++) {
+                    SCLogDebug("protocol %s: to_client: sub state:%s state:%u", AppProtoToString(a),
+                            sub_state_name, state);
+                    const char *state_name =
+                            AppLayerParserGetSubStateProgressName(a, s, state, STREAM_TOCLIENT);
+                    BUG_ON(state_name == NULL);
+                    SCLogDebug("protocol %s: to_client: sub state:%s state:%s", AppProtoToString(a),
+                            sub_state_name, state_name);
+                    if (DoParseAppSubStatePolicy(prefix, a, s, sub_state_name, state, state_name,
+                                max_state, STREAM_TOCLIENT, fw_policies, app_fw_policies) < 0)
+                        return -1;
+                }
+            }
+        } else {
             const uint8_t complete_state_ts =
-                (const uint8_t)AppLayerParserGetStateProgressCompletionStatus(a, STREAM_TOSERVER);
+                    (const uint8_t)AppLayerParserGetStateProgressCompletionStatus(
+                            a, STREAM_TOSERVER);
             for (uint8_t state = 0; state <= complete_state_ts; state++) {
                 const char *name =
                         AppLayerParserGetStateNameById(IPPROTO_TCP, a, state, STREAM_TOSERVER);
@@ -4196,9 +4292,9 @@ int DetectFirewallLoadDefaultPolicies(DetectEngineCtx *de_ctx)
                             fw_policies, app_fw_policies) < 0)
                     return -1;
             }
-
             const uint8_t complete_state_tc =
-                (const uint8_t)AppLayerParserGetStateProgressCompletionStatus(a, STREAM_TOCLIENT);
+                    (const uint8_t)AppLayerParserGetStateProgressCompletionStatus(
+                            a, STREAM_TOCLIENT);
             for (uint8_t state = 0; state <= complete_state_tc; state++) {
                 const char *name =
                         AppLayerParserGetStateNameById(IPPROTO_TCP, a, state, STREAM_TOCLIENT);
@@ -4207,7 +4303,7 @@ int DetectFirewallLoadDefaultPolicies(DetectEngineCtx *de_ctx)
                     return -1;
             }
         }
-
+    }
     return 0;
 }
 

src/detect.c

@@ -1741,20 +1741,40 @@ static inline void DetectRunAppendDefaultAppPolicyAlert(DetectEngineThreadCtx *d
  *        to look up configurable default policies later
  */
 static const struct DetectFirewallPolicy *DetectFirewallApplyDefaultAppPolicy(
-        DetectEngineThreadCtx *det_ctx, const struct DetectFirewallAppPolicy *policies,
+        DetectEngineThreadCtx *det_ctx, const struct DetectFirewallPolicies *policies,
         const DetectTransaction *tx, Packet *p, const AppProto alproto, const uint8_t direction,
         const uint8_t progress)
 {
     const struct DetectFirewallPolicy *policy;
+    SCLogDebug("packet %" PRIu64 ": tx type %u", PcapPacketCntGet(p), tx->tx_type);
+    if (tx->tx_type != 0) {
+        // TODO hard coded to HTTP/2 for now
+        BUG_ON(alproto != ALPROTO_HTTP2);
         if (direction & STREAM_TOSERVER) {
-        policy = &policies[alproto].ts[progress];
+            policy = &policies->http2_substates[tx->tx_type - 1].ts[progress];
+            SCLogDebug("packet %" PRIu64
+                       ", sub_state:%u, hook:%u, toserver, policy: action %02x scope %u",
+                    PcapPacketCntGet(p), tx->tx_type, progress, policy->action,
+                    policy->action_scope);
+        } else {
+            policy = &policies->http2_substates[tx->tx_type - 1].tc[progress];
+            SCLogDebug("packet %" PRIu64
+                       ", sub_state:%u, hook:%u, toclient, policy: action %02x scope %u",
+                    PcapPacketCntGet(p), tx->tx_type, progress, policy->action,
+                    policy->action_scope);
+        }
+
+    } else {
+        if (direction & STREAM_TOSERVER) {
+            policy = &policies->app[alproto].ts[progress];
             SCLogDebug("packet %" PRIu64 ", hook:%u, toserver, policy: action %02x scope %u",
                     PcapPacketCntGet(p), progress, policy->action, policy->action_scope);
         } else {
-        policy = &policies[alproto].tc[progress];
+            policy = &policies->app[alproto].tc[progress];
             SCLogDebug("packet %" PRIu64 ", hook:%u, toclient, policy: action %02x scope %u",
                     PcapPacketCntGet(p), progress, policy->action, policy->action_scope);
         }
+    }
 
     if (policy->action & ACTION_DROP) {
         SCLogDebug("dropping packet PKT_DROP_REASON_FW_DEFAULT_APP_POLICY");
@@ -1825,7 +1845,7 @@ static const struct DetectFirewallPolicy *DetectFirewallApplyDefaultAppPolicy(
  *  \retval DETECT_TX_FW_FC_OK no action needed
  */
 static enum DetectTxFirewallFlowControl DetectFirewallApplyDefaultPolicies(
-        DetectEngineThreadCtx *det_ctx, const struct DetectFirewallAppPolicy *policies,
+        DetectEngineThreadCtx *det_ctx, const struct DetectFirewallPolicies *policies,
         DetectTransaction *tx, Packet *p, const AppProto alproto, const uint8_t direction,
         const uint8_t start_hook, const uint8_t end_hook)
 {
@@ -1846,7 +1866,7 @@ static enum DetectTxFirewallFlowControl DetectFirewallApplyDefaultPolicies(
                 BOOL2STR(apply_to_packet));
 
         const struct DetectFirewallPolicy *policy = DetectFirewallApplyDefaultAppPolicy(
-                det_ctx, det_ctx->de_ctx->fw_policies->app, tx, p, alproto, direction, hook);
+                det_ctx, policies, tx, p, alproto, direction, hook);
         SCLogDebug("fw: hook:%u policy:%02x apply_to_packet:%s", hook, policy->action,
                 BOOL2STR(apply_to_packet));
         if (policy->action & ACTION_DROP) {
@@ -1961,9 +1981,9 @@ static enum DetectTxFirewallFlowControl DetectRunTxPreCheckFirewallPolicy(
                 s->app_progress_hook, tx->detect_progress, tx->detect_progress_orig);
         /* if this rule was after the state we expected meaning that there are
          * no rules for that state. Invoke the default policies. */
-        enum DetectTxFirewallFlowControl r = DetectFirewallApplyDefaultPolicies(det_ctx,
+        enum DetectTxFirewallFlowControl r =
-                det_ctx->de_ctx->fw_policies->app, tx, p, s->alproto, direction,
+                DetectFirewallApplyDefaultPolicies(det_ctx, det_ctx->de_ctx->fw_policies, tx, p,
-                tx->detect_progress_orig, s->app_progress_hook - 1);
+                        s->alproto, direction, tx->detect_progress_orig, s->app_progress_hook - 1);
         if (r != DETECT_TX_FW_FC_OK) {
             /* both SKIP and BREAK mean: no more fw rules to inspect.
              * SKIP applies to just this TX.
@@ -2124,8 +2144,8 @@ static void DetectRunTxFirewallApplyAccept(DetectEngineThreadCtx *det_ctx, Packe
                                               ? tx->tx_end_state
                                               : MIN(tx->tx_end_state, s->app_progress_hook + 1);
             enum DetectTxFirewallFlowControl r =
-                    DetectFirewallApplyDefaultPolicies(det_ctx, det_ctx->de_ctx->fw_policies->app,
+                    DetectFirewallApplyDefaultPolicies(det_ctx, det_ctx->de_ctx->fw_policies, tx, p,
-                            tx, p, s->alproto, direction, s->app_progress_hook + 1, last_hook);
+                            s->alproto, direction, s->app_progress_hook + 1, last_hook);
             if (r == DETECT_TX_FW_FC_BREAK) {
                 fw_state->fw_skip_app_filter = true;
                 return;
@@ -2187,8 +2207,8 @@ static int DetectTxFirewallNoRulesApplyPolicies(DetectEngineThreadCtx *det_ctx,
             SCLogDebug("tx.detect_progress_orig %u tx.tx_progress %u", tx->detect_progress_orig,
                     tx->tx_progress);
             enum DetectTxFirewallFlowControl r =
-                    DetectFirewallApplyDefaultPolicies(det_ctx, det_ctx->de_ctx->fw_policies->app,
+                    DetectFirewallApplyDefaultPolicies(det_ctx, det_ctx->de_ctx->fw_policies, tx, p,
-                            tx, p, alproto, flow_flags & (STREAM_TOSERVER | STREAM_TOCLIENT),
+                            alproto, flow_flags & (STREAM_TOSERVER | STREAM_TOCLIENT),
                             tx->detect_progress_orig, tx->tx_progress);
             SCLogDebug("r %u", r);
             if (r == DETECT_TX_FW_FC_BREAK)
@@ -2299,9 +2319,8 @@ static int DetectRunTxFirewallRuleNoMatch(DetectEngineThreadCtx *det_ctx, const
          * we have to invoke the default policy. We only check the current rule hook.
          * DROP is immediate, flow control for various accept options is handled by
          * the DetectRunTxPreCheckFirewallPolicy function for the next rule. */
-        const struct DetectFirewallPolicy *policy =
+        const struct DetectFirewallPolicy *policy = DetectFirewallApplyDefaultAppPolicy(det_ctx,
-                DetectFirewallApplyDefaultAppPolicy(det_ctx, det_ctx->de_ctx->fw_policies->app, tx,
+                det_ctx->de_ctx->fw_policies, tx, p, s->alproto, flow_flags, s->app_progress_hook);
-                        p, s->alproto, flow_flags, s->app_progress_hook);
         SCLogDebug("fw_last_for_progress policy %02x", policy->action);
         if (policy->action & ACTION_DROP) {
             return 1;

src/detect.h

@@ -950,6 +950,9 @@ struct DetectFirewallPolicies {
     /* hash table with a Signature object per default policy that has `alert` enabled. */
     HashTable *policy_signatures;
 
+    /* hard coded for now: http2 substates. Index at substate - 1. */
+    struct DetectFirewallAppPolicy http2_substates[2];
+
     /** app layer policies, one per alproto */
     struct DetectFirewallAppPolicy app[];
 };