Using SnmpDecodePacket for Encrypted/Authenticated Packets in GoSNMP about gosnmp HOT 5 OPEN

&{2c NoAuthNoPriv SnmpV3SecurityModel(0) <nil>   public GetResponse 0 1066889284 0 NoError 0 0 0 [{104 .1.3.6.1.2.1.1.7.0 Integer} {271070065 .1.3.6.1.2.1.2.2.1.10.1 Counter32} {100000000 .1.3.6.1.2.1.2.2.1.5.1 Gauge32} {[65 100 109 105 110 105 115 116 114 97 116 111 114] .1.3.6.1.2.1.1.4.0 OctetString} {<nil> .1.3.6.1.2.1.43.5.1.1.15.1 Null} {127.0.0.1 .1.3.6.1.2.1.4.21.1.1.127.0.0.1 IPAddress} {[0 21 153 55 118 43] .1.3.6.1.4.1.23.2.5.1.1.1.4.2 OctetString} {318870100 .1.3.6.1.2.1.1.3.0 TimeTicks}] {<nil>} {[] false   0 0 0}}

diff --git a/v3_usm.go b/v3_usm.go
index 9c6574a..cbcbdc2 100644
--- a/v3_usm.go
+++ b/v3_usm.go
@@ -1042,10 +1042,10 @@ func (sp *UsmSecurityParameters) unmarshal(flags SnmpV3MsgFlags, packet []byte,
        if flags&AuthNoPriv > 0 {
                // In case if the authentication protocol is not configured or set to NoAuth, then the packet cannot
                // be processed further
-               if sp.AuthenticationProtocol <= NoAuth {
-                       return 0, errors.New("error parsing SNMPv3 User Security Model: authentication parameters are not configured to parse incoming authenticated message")
+               if sp.AuthenticationProtocol >= NoAuth {
+                       copy(packet[cursor+2:cursor+len(macVarbinds[sp.AuthenticationProtocol])], macVarbinds[sp.AuthenticationProtocol][2:])
                }
-               copy(packet[cursor+2:cursor+len(macVarbinds[sp.AuthenticationProtocol])], macVarbinds[sp.AuthenticationProtocol][2:])
+               //  return 0, errors.New("error parsing SNMPv3 User Security Model: authentication parameters are not configured to parse incoming authenticated message")
        }
        cursor += count

@@ -1057,11 +1057,11 @@ func (sp *UsmSecurityParameters) unmarshal(flags SnmpV3MsgFlags, packet []byte,
        if msgPrivacyParameters, ok := rawMsgPrivacyParameters.(string); ok {
                sp.PrivacyParameters = []byte(msgPrivacyParameters)
                sp.Logger.Printf("Parsed privacyParameters %s", msgPrivacyParameters)
-               if flags&AuthPriv >= AuthPriv {
-                       if sp.PrivacyProtocol <= NoPriv {
-                               return 0, errors.New("error parsing SNMPv3 User Security Model: privacy parameters are not configured to parse incoming encrypted message")
-                       }
-               }
+               //      if flags&AuthPriv >= AuthPriv {
+               //              if sp.PrivacyProtocol <= NoPriv {
+               //                      return 0, errors.New("error parsing SNMPv3 User Security Model: privacy parameters are not configured to parse incoming encrypted message")
+               //              }
+               //      }
        }

% go run main.go
(*gosnmp.SnmpPacket)(0xc0000e6000)({
 Version: (gosnmp.SnmpVersion) 3,
 MsgFlags: (gosnmp.SnmpV3MsgFlags) AuthNoPriv,
 SecurityModel: (gosnmp.SnmpV3SecurityModel) UserSecurityModel,
 SecurityParameters: (*gosnmp.UsmSecurityParameters)(0xc0000a85b0)({
  mu: (sync.Mutex) {
   state: (int32) 0,
   sema: (uint32) 0
  },
  localAESSalt: (uint64) 0,
  localDESSalt: (uint32) 0,
  AuthoritativeEngineID: (string) (len=12) "\x80\x00\x00\xf8\x05\x00\x80c\xd2\xfe:\x00",
  AuthoritativeEngineBoots: (uint32) 3,
  AuthoritativeEngineTime: (uint32) 3169503,
  UserName: (string) (len=5) "admin",
  AuthenticationParameters: (string) (len=12) "\x7ff?\x86\xfdح\xb6\xc1\xbe\xdbv",
  PrivacyParameters: ([]uint8) {
  },
  AuthenticationProtocol: (gosnmp.SnmpV3AuthProtocol) SnmpV3AuthProtocol(0),
  PrivacyProtocol: (gosnmp.SnmpV3PrivProtocol) SnmpV3PrivProtocol(0),
  AuthenticationPassphrase: (string) "",
  PrivacyPassphrase: (string) "",
  SecretKey: ([]uint8) <nil>,
  PrivacyKey: ([]uint8) <nil>,
  Logger: (gosnmp.Logger) {
   logger: (gosnmp.LoggerInterface) <nil>
  }
 }),
 ContextEngineID: (string) (len=12) "\x80\x00\x00\xf8\x05\x00\x80c\xd2\xfe:\x00",
 ContextName: (string) "",
 Community: (string) "",
 PDUType: (gosnmp.PDUType) GetResponse,
 MsgID: (uint32) 297395,
 RequestID: (uint32) 297395,
 MsgMaxSize: (uint32) 2048,
 Error: (gosnmp.SNMPError) NoError,
 ErrorIndex: (uint8) 0,
 NonRepeaters: (uint8) 0,
 MaxRepetitions: (uint32) 0,
 Variables: ([]gosnmp.SnmpPDU) (len=1 cap=5) {
  (gosnmp.SnmpPDU) {
   Value: (int) 1,
   Name: (string) (len=22) ".1.3.6.1.2.1.2.2.1.8.1",
   Type: (gosnmp.Asn1BER) Integer
  }
 },
 Logger: (gosnmp.Logger) {
  logger: (gosnmp.LoggerInterface) <nil>
 },
 SnmpTrap: (gosnmp.SnmpTrap) {
  Variables: ([]gosnmp.SnmpPDU) <nil>,
  IsInform: (bool) false,
  Enterprise: (string) "",
  AgentAddress: (string) "",
  GenericTrap: (int) 0,
  SpecificTrap: (int) 0,
  Timestamp: (uint) 0
 }
})

2024/02/08 16:43:03 error parsing SNMPV3 contextEngineID: unknown field type: f0