Re: [net-snmp:patches] #1388 patch for bug 2923: snmpv3 bulkget errors result in double free core dump

[Bill F. <fe...@gm...>]

The memory leak is gone in the current V5-8-patches. I have not dug into
trying to bisect which change fixed it.

  Bill


On Tue, May 14, 2019 at 7:01 AM Bill Fenner <fe...@gm...> wrote:

> Perhaps getbulk no longer dumps core, but I can not get it to return
> anything but GENERR any more, and, it seems to leak memory.
>
> Any "large enough" request seems to fail in this way, e.g., snmpbulkget -v
> 3 ... -Cn 5 -Cr 50 sysUpTime sysUpTime sysUpTime sysUpTime sysUpTime .1
>
> This is particularly frustrating because code was added to 5.8 to rebuild
> a getbulk reply if it's too big.  But there was already code to not build
> the PDU too big, it's just not taking the v3 header into account properly
> (that's my best guess, at least).  So now there are two different
> mechanisms to send a "right-size" reply and they both don't work.  Around
> 5.8 release time I was working with Robert Story to fix this, but that
> effort kind of petered out and Robert's work didn't make it into git.
>
> Can anyone get getbulk to work in the current 5.8-patches with SNMPv3?
>
> I've attached a test script with 504 failing test cases when I run it
> against an unmodified V5-8-patches branch, and net-snmp leaks about a meg
> of RAM during the test.  This is an adaptation of my internal test to the
> net-snmp test framework; the complete test would use all supported values
> for -l, -a, -x but for now this is the simplest one using nanp.
>
> Thanks,
>   Bill
>
>
>
>
> On Wed, Apr 10, 2019 at 10:25 AM Bart Van Assche <
> bva...@us...> wrote:
>
>> This patch has been applied on the v5.8 and master branches. Thanks for
>> the patch!
>> ------------------------------
>>
>> * [patches:#1388] <https://sourceforge.net/p/net-snmp/patches/1388/>
>> patch for bug 2923: snmpv3 bulkget errors result in double free core dump*
>>
>> *Status:* open
>> *Group:* backport-needed
>> *Created:* Tue Mar 05, 2019 09:56 AM UTC by Sam Tannous
>> *Last Updated:* Tue Mar 05, 2019 09:56 AM UTC
>> *Owner:* nobody
>> *Attachments:*
>>
>>    - v3doublefree2.patch
>>    <https://sourceforge.net/p/net-snmp/patches/1388/attachment/v3doublefree2.patch>
>>    (14.2 kB; application/octet-stream)
>>
>> This is a patch for https://sourceforge.net/p/net-snmp/bugs/2923/ when
>> almost any v3 bulkget
>> error will cause a core dump of snmpd.
>> ------------------------------
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>