[SNMP4J] Issue with default context for SNMPv3

[Frank Fock]

Hi Mark,

This fix is needed cannot be undone. Nevertheless, you can simply
use "v2" for the v2 context and "v3" (or "") for the v3 (default) context.

This should not be a problem.

Best regards,
Frank


Am 09.01.2014 00:53, schrieb forum at friendlysnmp.org:
> (updated wrong subject)
>
> Frank,
>
> My old versions before upgrade were snmp4j-1.11 and snmp4j-agent-1.4
> My new versions are snmp4j-2.2.3 and snmp4j-agent-2.0.10a
>
> The line numbers for code in question in 
> org.snmp4j.agent.DefaultMOServer class:
> === snmp4j-agent-2.0.10a ===
> 271  public void register(ManagedObject mo, OctetString context)
> 272      throws DuplicateRegistrationException
> 273  {
> 274    if ((context == null) || (context.length() == 0)) {
>
> === snmp4j-agent-1.4 ===
> 282  public void register(ManagedObject mo, OctetString context)
> 283      throws DuplicateRegistrationException
> 284  {
> 285    if (context == null) {
>
> Compare lines #274 and #285 for the above versions.
> With default context (empty string) for the SNMPv3 the additional
> verification in line #274 "(context.length() == 0)" breaks my agent.
>
> It's possible that my BaseAgent implementation has bugs.
> However, it was working with snmp4j-1.11/snmp4j-agent-1.4
> and failed with snmp4j-2.2.3/snmp4j-agent-2.0.10a
>
> The problem appears for registering managed objects for different 
> contexts:
> v2 and default (empty string) v3.
>
> Thanks,
> Mark
>
> On 2013-12-28 04:28, Frank Fock wrote:
>> Hi Mark,
>>
>> You wrote that you upgraded SNMP4J but quoted SNMP4J-Agent
>> code. Have updated SNMP4J-Agent as well? To which version?
>> Why do you think that user (USM user?) contexts are related
>> to the MOServer.register(..) method?
>> (I would claim that they are not related)
>>
>> Best regards,
>> Frank
>>
>>
>> Am 25.12.2013 22:15, schrieb forum at friendlysnmp.org:
>>> Hi,
>>>
>>> I upgraded my working application from SNMP4J v1.11 to v2.2.3...
>>> There were some minor updates required in my code to use generics.
>>>
>>> I discovered a serious problem in my code with SNMP4J v2.2.3:
>>> empty default context for v3 user is not allowed any more
>>> if there is a v2 user defined as well.
>>>
>>> The problem is in a org.snmp4j.agent.DefaultMOServer class.
>>> The method register(ManagedObject mo, OctetString context) in v2.2.3
>>> makes following validation:
>>>    if ((context == null) || (context.length() == 0)) {
>>>    } else ...
>>>
>>> The v1.11 implementation had
>>>    if (context == null) {
>>>    } else ...
>>>
>>> The v2.2.3 validates default v3 empty context as v2 and
>>> throws DuplicateRegistrationException if v2 user is present.
>>> Am I missing something or this is a bug?
>>>
>>> Thanks,
>>> Mark
>>> _______________________________________________
>>> SNMP4J mailing list
>>> SNMP4J at agentpp.org
>>> http://lists.agentpp.org/mailman/listinfo/snmp4j
>
> _______________________________________________
> SNMP4J mailing list
> SNMP4J at agentpp.org
> https://s16675406.onlinehome-server.info/mailman/listinfo/snmp4j

-- 
---
AGENT++
Maximilian-Kolbe-Str. 10
73257 Koengen, Germany
https://agentpp.com
Phone: +49 7024 8688230
Fax:   +49 7024 8688231