Fix crash with long OID (> 50).

MAX_OID_LENGTH 128
shortbloke · Sep 11, 2021 · ca5c04f · ca5c04f
1 parent 2adad9a
commit ca5c04f
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Showing 6 changed files with 17 additions and 13 deletions.
diff --git a/CHANGELOG.md b/CHANGELOG.md
@@ -1,8 +1,12 @@
 # CHANGELOG for SNMP Manager For ESP8266/ESP32/Arduino
 
+## 1.1.5
+
+- Support longer OIDs. Change in v1.1.1 was incomplete
+
 ## 1.1.4
 
-- Fixes #12 where additional check for packet length was incorrect and unnecessary.
+- Fixes #12 where additional check for packet length was incorrect and unnecessary
 
 ## 1.1.3
 

diff --git a/library.properties b/library.properties
@@ -1,5 +1,5 @@
 name=SNMP Manager
-version=1.1.4
+version=1.1.5
 author=Martin Rowan <martin@martinrowan.co.uk>
 maintainer=Martin Rowan <martin@martinrowan.co.uk>
 sentence=An SNMP Manager library to make SNMP requests to other SNMP enabled devices.

diff --git a/src/Arduino_SNMP_Manager.h b/src/Arduino_SNMP_Manager.h
@@ -10,10 +10,8 @@
 #ifndef SNMP_PACKET_LENGTH
 #if defined(ESP32)
 #define SNMP_PACKET_LENGTH 1500 // This will limit the size of packets which can be handled.
-#elif defined(ESP8266)
-#define SNMP_PACKET_LENGTH 512 // This will limit the size of packets which can be handled. ESP8266 is unstable and crashes as this value approaches or exceeds1024. This appears to be a problem in the underlying WiFi or UDP implementation
 #else
-#define SNMP_PACKET_LENGTH 484 // This value may need to be made smaller for lower memory devices. This will limit the size of packets which can be handled.
+#define SNMP_PACKET_LENGTH 512 // This value may need to be made smaller for lower memory devices.
 #endif
 #endif
 
@@ -120,7 +118,7 @@ class SNMPManager
     bool begin();
     bool loop();
     bool testParsePacket(String testPacket);
-    char OIDBuf[50];
+    char OIDBuf[MAX_OID_LENGTH];
     UDP *_udp;
     void addHandler(ValueCallback *callback);
 
@@ -415,7 +413,7 @@ ValueCallback *SNMPManager::findCallback(IPAddress ip, const char *oid)
     {
         while (true)
         {
-            memset(OIDBuf, 0, 50);
+            memset(OIDBuf, 0, MAX_OID_LENGTH);
             strcat(OIDBuf, callbacksCursor->value->OID);
             if ((strcmp(OIDBuf, oid) == 0) && (callbacksCursor->value->ip == ip))
             {

diff --git a/src/BER.h b/src/BER.h
@@ -5,6 +5,10 @@
 #define SNMP_OCTETSTRING_MAX_LENGTH 1024
 #endif
 
+#ifndef MAX_OID_LENGTH
+#define MAX_OID_LENGTH 128
+#endif
+
 #include <Arduino.h>
 #include <math.h>
 
@@ -275,10 +279,10 @@ class OIDType : public BER_CONTAINER
     OIDType() : BER_CONTAINER(true, OID){};
     OIDType(char *value) : BER_CONTAINER(true, OID)
     {
-        strncpy(_value, value, 128);
+        strncpy(_value, value, MAX_OID_LENGTH);
     };
     ~OIDType(){};
-    char _value[128];
+    char _value[MAX_OID_LENGTH];
     int serialise(unsigned char *buf)
     {
 #ifdef DEBUG_BER

diff --git a/src/SNMPGet.h b/src/SNMPGet.h
@@ -76,7 +76,7 @@ class SNMPGet
 		int length = packet->serialise(_packetBuffer);
 		delete packet;
 		packet = 0;
-		_udp->beginPacket(ip, 161); // MFR: Trap 162, Get 161
+		_udp->beginPacket(ip, 161);
 		_udp->write(_packetBuffer, length);
 		return _udp->endPacket();
 	}

diff --git a/src/SNMPGetResponse.h b/src/SNMPGetResponse.h
@@ -29,7 +29,6 @@ class SNMPGetResponse
 
 bool SNMPGetResponse::parseFrom(unsigned char *buf)
 {
-	// SNMPPacket = new ComplexType(STRUCTURE); // ensure SNMPPacket is initialised to avoid crash in deconstructor
 	// confirm that the packet is a STRUCTURE
 	if (buf[0] != 0x30)
 	{
@@ -82,7 +81,7 @@ bool SNMPGetResponse::parseFrom(unsigned char *buf)
 					return false;
 				}
 				cursor = cursor->next;
-				EXPECTING = PDU; // temp
+				EXPECTING = PDU;
 			}
 			else
 			{
@@ -191,7 +190,6 @@ bool SNMPGetResponse::parseFrom(unsigned char *buf)
 				}
 				else
 				{
-					//                        tempCursor = ((ComplexType*)cursor->next->value)->_values;
 					tempCursor = tempCursor->next;
 					varBindsCursor = varBindsCursor->next;
 				}