For reasons unknown, I (srk) assumed that the orginal
substring domain matching algorithm was still in use,
where example.com would match eg. sexample.com
In fact the far more sensible label-based match, where
example.com (or .example.com) matches example.com and
www.example.com, but not sexample.com, has been in use
since release 2.22. This commit implements the 2.22 to 2.85
behaviour in the new domain-search code.
Thanks to Kevin Darbyshire-Bryant for spotting my mistake.
This extends query filtering support beyond what is currently possible
with the `--ipset` configuration option, by adding support for:
1) Specifying allowlists on a per-client basis, based on their
associated Linux connection track mark.
2) Dynamic configuration of allowlists via Ubus.
3) Reporting when a DNS query resolves or is rejected via Ubus.
4) DNS name patterns containing wildcards.
Disallowed queries are not forwarded; they are rejected
with a REFUSED error code.
Signed-off-by: Etan Kissling <etan_kissling@apple.com>
(addressed reviewer feedback)
Signed-off-by: Etan Kissling <etan.kissling@gmail.com>
This should be largely transparent, but it drastically
improves performance and reduces memory foot-print when
configuring large numbers domains of the form
local=/adserver.com/
or
local=/adserver.com/#
Lookup times now grow as log-to-base-2 of the number of domains,
rather than greater than linearly, as before.
The change makes multiple addresses associated with a domain work
address=/example.com/1.2.3.4
address=/example.com/5.6.7.8
It also handles multiple upstream servers for a domain better; using
the same try/retry alogrithms as non domain-specific servers. This
also applies to DNSSEC-generated queries.
Finally, some of the oldest and gnarliest code in dnsmasq has had
a significant clean-up. It's far from perfect, but it _is_ better.
Previously, without min-port or max-port configured, dnsmasq would
default to the compiled in defaults for those, which are 1024 and
65535. Now, when neither are configured, it defaults instead to
the kernel's ephemeral port range, which is typically
32768 to 60999 on Linux systems. This change eliminates the
possibility that dnsmasq may be using a registered port > 1024
when a long-running daemon starts up and wishes to claim it.
This change does likely slighly reduce the number of random ports
and therefore the protection from reply spoofing. The older
behaviour can be restored using the min-port and max-port config
switches should that be a concern.
CVE-2021-3448 applies.
It's possible to specify the source address or interface to be
used when contacting upstream nameservers: server=8.8.8.8@1.2.3.4
or server=8.8.8.8@1.2.3.4#66 or server=8.8.8.8@eth0, and all of
these have, until now, used a single socket, bound to a fixed
port. This was originally done to allow an error (non-existent
interface, or non-local address) to be detected at start-up. This
means that any upstream servers specified in such a way don't use
random source ports, and are more susceptible to cache-poisoning
attacks.
We now use random ports where possible, even when the
source is specified, so server=8.8.8.8@1.2.3.4 or
server=8.8.8.8@eth0 will use random source
ports. server=8.8.8.8@1.2.3.4#66 or any use of --query-port will
use the explicitly configured port, and should only be done with
understanding of the security implications.
Note that this change changes non-existing interface, or non-local
source address errors from fatal to run-time. The error will be
logged and communiction with the server not possible.
From 606d638918edb0e0ec07fe27eb68d06fb5ebd981 Mon Sep 17 00:00:00 2001
From: Miao Wang <shankerwangmiao@gmail.com>
Date: Fri, 4 Dec 2020 09:59:37 +0800
Subject: [PATCH v2] pxe: support pxe clients with custom vendor-class
According to UEFI[1] and PXE[2] specs, PXE clients are required to have
`PXEClient` identfier in the vendor-class field of DHCP requests, and
PXE servers should also include that identifier in their responses.
However, the firmware of servers from a few vendors[3] are customized to
include a different identifier. This patch adds an option named
`dhcp-pxe-vendor` to provide a list of such identifiers. The identifier
used in responses sent from dnsmasq is identical to that in the coresponding
request.
[1]: https://uefi.org/sites/default/files/resources/UEFI%20Spec%202.8B%20May%202020.pdf
[2]: http://www.pix.net/software/pxeboot/archive/pxespec.pdf
[3]: For instance, TaiShan servers from Huawei, which are Arm64-based,
send `HW-Client` in PXE requests up to now.
Signed-off-by: Miao Wang <shankerwangmiao@gmail.com>
Same as for the dbus, allow specifying ubus service name (namespace) on
the command line as an optional argument to --enable-ubus option.
Signed-off-by: Oldřich Jedlička <oldium.pro@gmail.com>
Error with prefixed address assignment. When it is calculating number of
addresses from prefixlen, it rotates only 32bit int instead of 64b uint.
Only result is assigned to 64b variable.
Two examples:
dhcp-host=[2000::1230:0:0/92],correct-prefix
dhcp-host=[2000::1234:5678:0/92],incorrect-prefix
If prefix length is lower than 96, the result is zero. It means
incorrect-prefix is not refused as it should. Fix is simple, attaching
patch with it. Just rotate 64b int.
There was discussion in the past regarding DHCPv6 NTP server option
which needs special subclassing per RFC5908.
Patch adds support for unicast, multicast IPv6 address and for FQDN string,
preserving possibly used (as suggested earlier) hex value.
Unfortunately it's still not fully free from limitations - only address list or
only fqdn value list is possible, not mixed due current
state option parsing & flagging.
Errors encountered if building with 'NO_DHCP6' introduced by
commit 137286e9ba
option.c: In function 'dhcp_config_free':
option.c:1040:24: error: 'struct dhcp_config' has no member named 'addr6'; did you mean 'addr'?
for (addr = config->addr6; addr; addr = tmp)
^~~~~
addr
option.c: In function 'one_opt':
option.c:3227:7: error: 'struct dhcp_config' has no member named 'addr6'; did you mean 'addr'?
new->addr6 = NULL;
^~~~~
addr
Wrap new code in ifdef HAVE_DHCP6
Signed-off-by: Kevin Darbyshire-Bryant <ldir@darbyshire-bryant.me.uk>
When a request matching the clid or mac address is
recieved the server will iterate over all candidate
addresses until it find's one that is not already
leased to a different clid/iaid and advertise
this address.
Using multiple reservations for a single host makes it
possible to maintain a static leases only configuration
which support network booting systems with UEFI firmware
that request a new address (a new SOLICIT with a new IA_NA
option using a new IAID) for different boot modes, for
instance 'PXE over IPv6', and 'HTTP-Boot over IPv6'. Open
Virtual Machine Firmware (OVMF) and most UEFI firmware
build on the EDK2 code base exhibit this behaviour.
The idea of this option was already discussed years ago on the mailing
list:
https://dnsmasq-discuss.thekelleys.org.narkive.com/ZoFQNaGo/always-ignore-client-identifier#post4
In our production environnement, we discovered that some devices are
using 'client identifier' not unique at all, resulting on IP addresses
conflicts between several devices (we saw up to four devices using same
IP address).
The root cause is probably a buggy operating system/configuration of
decices, but this patch add a configuration workaround on server side
when fixing clients is impossible.
Signed-off-by: Charles Daymand <charles.daymand@wifirst.fr>
Signed-off-by: Florent Fourcot <florent.fourcot@wifirst.fr>
If the cache size is very large, the malloc() call will overflow
on 32 bit platforms and dnsmasq will crash. Limit to an order of
magnitude less.
Thanks to Lili Xu for spotting this.
Hi Simon,
master has a build error when building without HAVE_DHCPv6
option.c: In function 'dhcp_context_free':
option.c:1042:15: error: 'struct dhcp_context' has no member named 'template_interface'
free(ctx->template_interface);
Sadly, need to put in a little conditional compilation ifdef'erey
Simplest patch in the world attached
Cheers,
Kevin D-B
012C ACB2 28C6 C53E 9775 9123 B3A2 389B 9DE2 334A
From 061eb8599636bb360e0b7fa5986935b86db39497 Mon Sep 17 00:00:00 2001
From: Kevin Darbyshire-Bryant <ldir@darbyshire-bryant.me.uk>
Date: Mon, 10 Dec 2018 10:07:33 +0000
Subject: [PATCH] option: fix non DHCPv6 build error
option.c: In function 'dhcp_context_free':
option.c:1042:15: error: 'struct dhcp_context' has no member named 'template_interface'
free(ctx->template_interface);
^~
Signed-off-by: Kevin Darbyshire-Bryant <ldir@darbyshire-bryant.me.uk>
This time I have a little bit more controversal patches. But I think
still useful. They fixes memory leaks that might occur in some cases.
Most dnsmasq errors is fatal, so it does not matter. But some are not.
Some parts are reloaded on SIGHUP signal, so it might leak more than once.
Some example when it changes the failures. Use dhcp-options file with
this content:
tag:error,vendor:redhat
option:ntp-server,1.2.3.4.5
option6:ntp-server,[:::]
Is not fatal and dnsmasq will start. On each reload command, it would
leak some memory. I validated it using valgrind --leak-check=full
dnsmasq -d. This patch fixes it. It introduces something that might be
considered constructor and destructor of selected structures.
In an era where everything has an MMU, this looks like
an anachronism, and it adds to (Ok, multiplies!) the
combinatorial explosion of compile-time options.
Make options bits derived from size and count. Use size of option bits
and last supported bit in computation. No new change would be required
when new options are added. Just change OPT_LAST constant.
This was the source of a large number of #ifdefs, originally
included for use with old embedded libc versions. I'm
sure no-one wants or needs IPv6-free code these days, so this
is a move towards more maintainable code.
But make auth-server required when any auth-zones are defined.
The "glue record" field in auth-server is needed to synthesise
SOA and NS records in auth zones, so the --auth-server has to
be specified. If makes sense, however to define one or more
auth-zones that appear within the normal recursive DNS service
without actually acting as an authoritative DNS server on
any interface. Hence making the interface field optional.
