[Dnsmasq-discuss] segfault when setting pxe-server to empty value in dnsmasq 2.66

[Simon Kelley]

On 27/06/13 03:56, Patrick McLean wrote:
> Hi, running dnsmasq 2.66 we had a config that set pxe-server to a
> blank value, and that was causing dnsmasq to segfault every time it
> recieved a dhcp request.
>
> I have attached a backtrace (generated when compiled with gcc 4.8's
> -fsanitize=address), I manually printed some relevant variables as
> well.
>
>

Thanks for this, and the additional stuff you sent. I couldn't believe
that a straightforward "crash on empty option" bug had survived
un-noticed thus far, and I was right. It turns out that to trigger the
problem, you need an empty string option, and a client which insists
that such options are send zero-terminated.

Fix here.

http://thekelleys.org.uk/gitweb/?p=dnsmasq.git;a=commit;h=625ac28c61b0a5e6a252db00d72fbac6d88718fd


Thanks for your help.

Cheers,

Simon.