FYI: Shared the requested PCAP file directly with Simon as it contains sensitive information (browsing behavior).
Best, Dominik On Mon, 2019-10-07 at 17:58 +0100, Simon Kelley wrote: > On 05/10/2019 11:22, Dominik wrote: > > Hey all, > > > > I'm reporting a bug on behold of another user that does not want to > > contact this mailing list himself. > > > > Short summary: With DNSSEC enabled, the user sees a crash when dnsmasq > > wants to retry a query after the upstream DNS server responded before > > with "REFUSED DNSKEY". At least this is my theory so far. > > > > This crash happens with dnsmasq v2.80. > > > > The backtrace shows that the error is encountered at > > http://thekelleys.org.uk/gitweb/?p=dnsmasq.git;a=blob;f=src/forward.c;h=3dd863335b1320477c56b7c50112bfe241cfd574;hb=91421cb7575df7bb211dacc30dc7c7c715c38299#l303 > > > > if (forward->sentto->addr.sa.sa_family == AF_INET) > > > > With gdb, we saw that the crash happens when dnsmasq tries to access > > forward->sentto->...: > > (gdb) p forward > > $1 = (struct frec *) 0x5569e433b0e0 > > (gdb) p forward->sentto > > $2 = (struct server *) 0x0 > > (gdb) p forward->sentto->addr > > Cannot access memory at address 0x0 > > (gdb) p forward->sentto->addr.sa > > Cannot access memory at address 0x0 > > (gdb) p forward->sentto->addr.sa.sa_family > > Cannot access memory at address 0x0 > > > > Further details can be found in the issue ticket below. > > I'll man-in-the-middle things back and forth if necessary. > > https://github.com/pi-hole/FTL/issues/645 > > > > Thanks for this. There's lots of useful information already. > > I think that the problem may be related to having both 127.0.2.1 and ::1 > as servers: The REFUSED reply from one causes dnsmasq to retry the query > on the other and somewhere in that process, internal datastructures are > mangled. > > What would be really useful would be to see more history to the packet > dumps, and preferably a copy of the pcap file. Could you help get those? > > Cheers, > > Simon. > > > _______________________________________________ > Dnsmasq-discuss mailing list > Dnsmasqfirstname.lastname@example.org > http://lists.thekelleys.org.uk/mailman/listinfo/dnsmasq-discuss _______________________________________________ Dnsmasq-discuss mailing list Dnsmasqemail@example.com http://lists.thekelleys.org.uk/mailman/listinfo/dnsmasq-discuss