From 3294103e06e95fb72f0fdd98abb181569f5fe6a9 Mon Sep 17 00:00:00 2001
From: Richard Ramos <info@richardramos.me>
Date: Sun, 4 Apr 2021 14:42:08 -0400
Subject: [PATCH] fix: index out of bounds when querying stored messages

---
 cmd/root.go                               |  6 ++++--
 waku/v2/protocol/waku_store/waku_store.go | 12 +++++++++---
 2 files changed, 13 insertions(+), 5 deletions(-)

diff --git a/cmd/root.go b/cmd/root.go
index 2f6a9118..ad7f1ddd 100644
--- a/cmd/root.go
+++ b/cmd/root.go
@@ -186,8 +186,10 @@ var rootCmd = &cobra.Command{
 
 			fmt.Println(fmt.Sprint("Page Size: ", response.PagingInfo.PageSize))
 			fmt.Println(fmt.Sprint("Direction: ", response.PagingInfo.Direction))
-			fmt.Println(fmt.Sprint("Cursor - ReceivedTime: ", response.PagingInfo.Cursor.ReceivedTime))
-			fmt.Println(fmt.Sprint("Cursor - Digest: ", hex.EncodeToString(response.PagingInfo.Cursor.Digest)))
+			if response.PagingInfo.Cursor != nil {
+				fmt.Println(fmt.Sprint("Cursor - ReceivedTime: ", response.PagingInfo.Cursor.ReceivedTime))
+				fmt.Println(fmt.Sprint("Cursor - Digest: ", hex.EncodeToString(response.PagingInfo.Cursor.Digest)))
+			}
 			fmt.Println("Messages:")
 			for i, msg := range response.Messages {
 				fmt.Println(fmt.Sprint(i, "- ", string(msg.Payload))) // Normaly you'd have to decode these, but i'm using v0
diff --git a/waku/v2/protocol/waku_store/waku_store.go b/waku/v2/protocol/waku_store/waku_store.go
index d0c5f6be..85ab9502 100644
--- a/waku/v2/protocol/waku_store/waku_store.go
+++ b/waku/v2/protocol/waku_store/waku_store.go
@@ -78,7 +78,7 @@ func paginateWithIndex(list []IndexedWakuMessage, pinfo *protocol.PagingInfo) (r
 		}
 	}
 
-	foundIndex := findIndex(&msgList, cursor)
+	foundIndex := findIndex(msgList, cursor)
 	if foundIndex == -1 { // the cursor is not valid
 		return nil, &protocol.PagingInfo{PageSize: 0, Cursor: pinfo.Cursor, Direction: pinfo.Direction}
 	}
@@ -95,6 +95,9 @@ func paginateWithIndex(list []IndexedWakuMessage, pinfo *protocol.PagingInfo) (r
 		}
 		s = foundIndex + 1 // non inclusive
 		e = foundIndex + retrievedPageSize
+		if e < 0 {
+			e = 0
+		}
 		newCursor = msgList[e].index // the new cursor points to the end of the page
 	case protocol.PagingInfo_BACKWARD: // backward pagination
 		remainingMessages := foundIndex
@@ -104,6 +107,9 @@ func paginateWithIndex(list []IndexedWakuMessage, pinfo *protocol.PagingInfo) (r
 			foundIndex = foundIndex + 1
 		}
 		s = foundIndex - retrievedPageSize
+		if s >= len(msgList) {
+			s = len(msgList) - 1
+		}
 		e = foundIndex - 1
 		newCursor = msgList[s].index // the new cursor points to the begining of the page
 	}
@@ -308,10 +314,10 @@ func indexedWakuMessageComparison(x, y IndexedWakuMessage) int {
 	return indexComparison(x.index, y.index)
 }
 
-func findIndex(msgList *[]IndexedWakuMessage, index *protocol.Index) int {
+func findIndex(msgList []IndexedWakuMessage, index *protocol.Index) int {
 	// returns the position of an IndexedWakuMessage in msgList whose index value matches the given index
 	// returns -1 if no match is found
-	for i, indexedWakuMessage := range *msgList {
+	for i, indexedWakuMessage := range msgList {
 		if bytes.Compare(indexedWakuMessage.index.Digest, index.Digest) == 0 && indexedWakuMessage.index.ReceivedTime == index.ReceivedTime {
 			return i
 		}