[Dnsmasq-discuss] dnsmasqd crash

[Justin Jose]

Hi Simon.

The issue is reproducible on my device. It is very difficult for me to upgrade the current version to the latest.

But after close investigation I found a bug in our code and the issue is resolved now. Basically domain in the 'forward_query' function should
always point to the current server's domain. 

Thanks
Justin
________________________________________
From: Dnsmasq-discuss <dnsmasq-discuss-bounces at lists.thekelleys.org.uk> on behalf of Simon Kelley <simon at thekelleys.org.uk>
Sent: Monday, 26 June 2017 8:49 a.m.
To: dnsmasq-discuss at lists.thekelleys.org.uk
Subject: Re: [Dnsmasq-discuss] dnsmasqd crash

Can you reproduce the crash? What triggers it?

2.55 is seven years old now, and predates our use of git, so it's pretty
difficult to point to a fix, but I suspect that this bug is long gone.
Finding how to reproduce it and showing that it doesn't happen with
newer releases would be the best way.




Cheers,

Simon.

On 20/06/17 22:44, Justin Jose wrote:
> Hi Kevin,
>
> Thank you for the response. Here are my answers for your questions.
>
> Q. What version of dnsmasq?
>
> [Ans] The dnsmasq version I am using is 2.55.
>
> Q. hostname_isequal is used in quite a few places and should never be
> passed a null pointer, so in my opinion the fix is a sticking plaster
> over the issue and has the potential result of leaving null pointers
> hanging around for other functions to fall over anyway.  The root cause
> should be found and squished.  Any idea which particular call to
> hostname_isequal was involved?
>
> [Ans:] When the crash happened, the call to hostname_isequal is occured from forward_query at round line number 500.
>            I am not sure the reason for the NULL arguments here.
>
> Regards
> Justin
> ________________________________________
> From: Dnsmasq-discuss <dnsmasq-discuss-bounces at lists.thekelleys.org.uk> on behalf of Kevin Darbyshire-Bryant <kevin at darbyshire-bryant.me.uk>
> Sent: Monday, 19 June 2017 8:56 p.m.
> To: dnsmasq-discuss at lists.thekelleys.org.uk
> Subject: Re: [Dnsmasq-discuss] dnsmasqd crash
>
> On 19/06/17 01:02, Justin Jose wrote:
>> ​​​Hi,
>>
>>
>> I got a couple of dnsmasqd crash and on investigating I found the crash
>> is due to accessing a NULL pointer.
>
> What version of dnsmasq?
>
>>
>> I have a fix for this problem and attached with this mail.
>>
>>
>> Would you have any suggestion for this fix?
>
> hostname_isequal is used in quite a few places and should never be
> passed a null pointer, so in my opinion the fix is a sticking plaster
> over the issue and has the potential result of leaving null pointers
> hanging around for other functions to fall over anyway.  The root cause
> should be found and squished.  Any idea which particular call to
> hostname_isequal was involved?
>
> Cheers,
>
> Kevin
>
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