From 4443254fb92710c31b1830bc13d3d642f3c2917f Mon Sep 17 00:00:00 2001
From: Aliaksandr Valialkin <valyala@gmail.com>
Date: Thu, 18 Mar 2021 14:52:49 +0200
Subject: [PATCH] lib/storage: prevent from infinite loop if
 `{__graphite__="..."}` filter matches a metric name with `*`, `[` or `{`
 chars

The idea has been borrowed from https://github.com/VictoriaMetrics/VictoriaMetrics/pull/1137
---
 docs/CHANGELOG.md      |  2 ++
 lib/storage/storage.go | 41 +++++++++++++++++++++++------------------
 2 files changed, 25 insertions(+), 18 deletions(-)

diff --git a/docs/CHANGELOG.md b/docs/CHANGELOG.md
index ada4f3bf6e..89f1f05df4 100644
--- a/docs/CHANGELOG.md
+++ b/docs/CHANGELOG.md
@@ -9,6 +9,8 @@
   * `process_resident_memory_peak_bytes` - peak RSS usage for the process.
   * `process_virtual_memory_peak_bytes` - peak virtual memory usage for the process.
 
+* BUGFIX: prevent from infinite loop on `{__graphite__="..."}` filters when a metric name contains `*`, `{` or `[` chars.
+
 
 # [v1.56.0](https://github.com/VictoriaMetrics/VictoriaMetrics/releases/tag/v1.56.0)
 
diff --git a/lib/storage/storage.go b/lib/storage/storage.go
index 146310ceea..a1aa646781 100644
--- a/lib/storage/storage.go
+++ b/lib/storage/storage.go
@@ -1,6 +1,7 @@
 package storage
 
 import (
+	"bytes"
 	"fmt"
 	"io"
 	"io/ioutil"
@@ -15,6 +16,7 @@ import (
 	"time"
 	"unsafe"
 
+	"github.com/VictoriaMetrics/VictoriaMetrics/lib/bytesutil"
 	"github.com/VictoriaMetrics/VictoriaMetrics/lib/cgroup"
 	"github.com/VictoriaMetrics/VictoriaMetrics/lib/encoding"
 	"github.com/VictoriaMetrics/VictoriaMetrics/lib/fasttime"
@@ -1122,14 +1124,16 @@ func (s *Storage) SearchTagValueSuffixes(accountID, projectID uint32, tr TimeRan
 }
 
 // SearchGraphitePaths returns all the matching paths for the given graphite query on the given tr.
-//
-// If more than maxPaths paths is found, then only the first maxPaths paths is returned.
 func (s *Storage) SearchGraphitePaths(accountID, projectID uint32, tr TimeRange, query []byte, maxPaths int, deadline uint64) ([]string, error) {
-	queryStr := string(query)
-	n := strings.IndexAny(queryStr, "*[{")
+	return s.searchGraphitePaths(accountID, projectID, tr, nil, query, maxPaths, deadline)
+}
+
+func (s *Storage) searchGraphitePaths(accountID, projectID uint32, tr TimeRange, qHead, qTail []byte, maxPaths int, deadline uint64) ([]string, error) {
+	n := strings.IndexAny(bytesutil.ToUnsafeString(qTail), "*[{")
 	if n < 0 {
-		// Verify that the query matches a metric name.
-		suffixes, err := s.SearchTagValueSuffixes(accountID, projectID, tr, nil, query, '.', 1, deadline)
+		// Verify that qHead matches a metric name.
+		qHead = append(qHead, qTail...)
+		suffixes, err := s.SearchTagValueSuffixes(accountID, projectID, tr, nil, qHead, '.', 1, deadline)
 		if err != nil {
 			return nil, err
 		}
@@ -1141,9 +1145,10 @@ func (s *Storage) SearchGraphitePaths(accountID, projectID uint32, tr TimeRange,
 			// The query matches a metric name with additional suffix.
 			return nil, nil
 		}
-		return []string{queryStr}, nil
+		return []string{string(qHead)}, nil
 	}
-	suffixes, err := s.SearchTagValueSuffixes(accountID, projectID, tr, nil, query[:n], '.', maxPaths, deadline)
+	qHead = append(qHead, qTail[:n]...)
+	suffixes, err := s.SearchTagValueSuffixes(accountID, projectID, tr, nil, qHead, '.', maxPaths, deadline)
 	if err != nil {
 		return nil, err
 	}
@@ -1153,34 +1158,34 @@ func (s *Storage) SearchGraphitePaths(accountID, projectID uint32, tr TimeRange,
 	if len(suffixes) >= maxPaths {
 		return nil, fmt.Errorf("more than maxPaths=%d suffixes found", maxPaths)
 	}
-	qPrefixStr := queryStr[:n]
-	qTail := ""
-	qNode := queryStr[n:]
+	qNode := qTail[n:]
+	qTail = nil
 	mustMatchLeafs := true
-	if m := strings.IndexByte(qNode, '.'); m >= 0 {
+	if m := bytes.IndexByte(qNode, '.'); m >= 0 {
 		qTail = qNode[m+1:]
 		qNode = qNode[:m+1]
 		mustMatchLeafs = false
 	}
-	re, err := getRegexpForGraphiteQuery(qNode)
+	re, err := getRegexpForGraphiteQuery(string(qNode))
 	if err != nil {
 		return nil, err
 	}
+	qHeadLen := len(qHead)
 	var paths []string
 	for _, suffix := range suffixes {
 		if len(paths) > maxPaths {
-			paths = paths[:maxPaths]
-			break
+			return nil, fmt.Errorf("more than maxPath=%d paths found", maxPaths)
 		}
 		if !re.MatchString(suffix) {
 			continue
 		}
 		if mustMatchLeafs {
-			paths = append(paths, qPrefixStr+suffix)
+			qHead = append(qHead[:qHeadLen], suffix...)
+			paths = append(paths, string(qHead))
 			continue
 		}
-		q := qPrefixStr + suffix + qTail
-		ps, err := s.SearchGraphitePaths(accountID, projectID, tr, []byte(q), maxPaths, deadline)
+		qHead = append(qHead[:qHeadLen], suffix...)
+		ps, err := s.searchGraphitePaths(accountID, projectID, tr, qHead, qTail, maxPaths, deadline)
 		if err != nil {
 			return nil, err
 		}