fix(tmplexec): memory blowup in multiproto (#6258)

* bugfix: fix memory blowup using previousEvent for multi-proto execution

* refactor(tmplexec): uses supported protocol types

Signed-off-by: Dwi Siswanto <git@dw1.io>

* add co-author

Co-authored-by: Nakul Bharti <knakul853@users.noreply.github.com>
Signed-off-by: Dwi Siswanto <git@dw1.io>

* refactor(tmplexec): mv builder inside loop scope

Signed-off-by: Dwi Siswanto <git@dw1.io>

* refactor(tmplexec): skip existing keys in `FillPreviousEvent`

The `FillPreviousEvent` func was modified to
prevent overwriting/duplicating entries in the
previous map.

It now checks if a key `k` from
`event.InternalEvent` already exists in the
previous map. If it does, the key is skipped. This
ensures that if `k` was already set (potentially
w/o a prefix), it's not re-added with an `ID_`
prefix.

Additionally, keys in `event.InternalEvent` that
already start with the current `ID_` prefix are
also skipped to avoid redundant prefixing.

This change simplifies the logic by removing the
`reqTypeWithIndexRegex` and directly addresses the
potential for duplicate / incorrectly prefixed
keys when `event.InternalEvent` grows during
protocol request execution.

Signed-off-by: Dwi Siswanto <git@dw1.io>

* chore(tmplexec): naming convention, `ID` => `protoID`

Signed-off-by: Dwi Siswanto <git@dw1.io>

* chore(tmplexec): it's request ID lol sorry

Signed-off-by: Dwi Siswanto <git@dw1.io>

---------

Signed-off-by: Dwi Siswanto <git@dw1.io>
Co-authored-by: Ice3man <nizamulrana@gmail.com>
Co-authored-by: Nakul Bharti <knakul853@users.noreply.github.com>

pkg/tmplexec/generic/exec.go

@@ -1,13 +1,13 @@
 package generic
 
 import (
-	"strings"
 	"sync/atomic"
 
 	"github.com/projectdiscovery/gologger"
 	"github.com/projectdiscovery/nuclei/v3/pkg/output"
 	"github.com/projectdiscovery/nuclei/v3/pkg/protocols"
 	"github.com/projectdiscovery/nuclei/v3/pkg/scan"
+	"github.com/projectdiscovery/nuclei/v3/pkg/tmplexec/utils"
 	mapsutil "github.com/projectdiscovery/utils/maps"
 )
 
@@ -64,17 +64,9 @@ func (g *Generic) ExecuteWithResults(ctx *scan.ScanContext) error {
 				// ideally this should never happen since protocol exits on error and callback is not called
 				return
 			}
-			ID := req.GetID()
+
-			if ID != "" {
+			utils.FillPreviousEvent(req.GetID(), event, previous)
-				builder := &strings.Builder{}
+
-				for k, v := range event.InternalEvent {
-					builder.WriteString(ID)
-					builder.WriteString("_")
-					builder.WriteString(k)
-					_ = previous.Set(builder.String(), v)
-					builder.Reset()
-				}
-			}
 			if event.HasOperatorResult() {
 				g.results.CompareAndSwap(false, true)
 			}

pkg/tmplexec/multiproto/multi.go

@@ -2,7 +2,6 @@ package multiproto
 
 import (
 	"strconv"
-	"strings"
 	"sync/atomic"
 
 	"github.com/projectdiscovery/nuclei/v3/pkg/output"
@@ -10,6 +9,7 @@ import (
 	"github.com/projectdiscovery/nuclei/v3/pkg/protocols/common/generators"
 	"github.com/projectdiscovery/nuclei/v3/pkg/scan"
 	"github.com/projectdiscovery/nuclei/v3/pkg/templates/types"
+	"github.com/projectdiscovery/nuclei/v3/pkg/tmplexec/utils"
 	mapsutil "github.com/projectdiscovery/utils/maps"
 	stringsutil "github.com/projectdiscovery/utils/strings"
 )
@@ -90,17 +90,7 @@ func (m *MultiProtocol) ExecuteWithResults(ctx *scan.ScanContext) error {
 				return
 			}
 
-			ID := req.GetID()
+			utils.FillPreviousEvent(req.GetID(), event, previous)
-			if ID != "" {
-				builder := &strings.Builder{}
-				for k, v := range event.InternalEvent {
-					builder.WriteString(ID)
-					builder.WriteString("_")
-					builder.WriteString(k)
-					_ = previous.Set(builder.String(), v)
-					builder.Reset()
-				}
-			}
 
 			// log event and generate result for the event
 			ctx.LogEvent(event)

pkg/tmplexec/utils/utils.go

@@ -0,0 +1,34 @@
+package utils
+
+import (
+	"strings"
+
+	"github.com/projectdiscovery/nuclei/v3/pkg/output"
+	mapsutil "github.com/projectdiscovery/utils/maps"
+)
+
+// FillPreviousEvent is a helper function to get the previous event from the event
+// without leading to duplicate prefixes
+func FillPreviousEvent(reqID string, event *output.InternalWrappedEvent, previous *mapsutil.SyncLockMap[string, any]) {
+	if reqID == "" {
+		return
+	}
+
+	for k, v := range event.InternalEvent {
+		if _, ok := previous.Get(k); ok {
+			continue
+		}
+
+		if strings.HasPrefix(k, reqID+"_") {
+			continue
+		}
+
+		var builder strings.Builder
+
+		builder.WriteString(reqID)
+		builder.WriteString("_")
+		builder.WriteString(k)
+
+		_ = previous.Set(builder.String(), v)
+	}
+}