This resolves the issue that prompted the filing of
https://bugzilla.redhat.com/show_bug.cgi?id=928638
(although the request there is for something much larger and more
general than this patch).
commit f3868259ca disabled the
forwarding to upstream DNS servers of unresolved DNS requests for
names that had no domain, but were just simple host names (no "."
character anywhere in the name). While this behavior is frowned upon
by DNS root servers (that's why it was changed in libvirt), it is
convenient in some cases, and since dnsmasq can be configured to allow
it, it must not be strictly forbidden.
This patch restores the old behavior, but since it is usually
undesirable, restoring it requires specification of a new option in
the network config. Adding the attribute "forwardPlainNames='yes'" to
the <dns> elemnt does the trick - when that attribute is added to a
network config, any simple hostnames that can't be resolved by the
network's dnsmasq instance will be forwarded to the DNS servers listed
in the host's /etc/resolv.conf for an attempt at resolution (just as
any FQDN would be forwarded).
When that attribute *isn't* specified, unresolved simple names will
*not* be forwarded to the upstream DNS server - this is the default
behavior.
This reverts commit 383ebc4694.
We decided the xml for this feature needed more thought to make sure
we are doing it the best way, in particular wrt option values that
have multiple items.
Originally, only a host name was used to associate a
DHCPv6 request with a specific IPv6 address. Further testing
demonstrates that this is an unreliable method and, instead,
a client-id or DUID needs to be used. According to DHCPv6
standards, this id can be a duid-LLT, duid-LL, or duid-UUID
even though dnsmasq will accept almost any text string.
Although validity checking of a specified string makes sure it is
hexadecimal notation with bytes separated by colons, there is no
rigorous check to make sure it meets the standard.
Documentation and schemas have been updated.
Signed-off-by: Gene Czarcinski <gene@czarc.net>
Signed-off-by: Laine Stump <laine@laine.org>
This patch adds support for a new <option>-Tag in the <dhcp> block of
network configs, based on a subset of the fifth proposal by Laine
Stump in the mailing list discussion at
https://www.redhat.com/archives/libvir-list/2012-November/msg01054.html.
Any such defined option will result in a dhcp-option=<number>,"<value>"
statement in the generated dnsmasq configuration file.
Currently, DHCP options can be specified by number only and there is
no whitelisting or blacklisting of option numbers, which should
probably be added.
Signed-off-by: Pieter Hollants <pieter@hollants.com>
Signed-off-by: Laine Stump <laine@laine.org>
This patch resolves the problem reported in:
https://bugzilla.redhat.com/show_bug.cgi?id=886663
The source of the problem was the fix for CVE 2011-3411:
https://bugzilla.redhat.com/show_bug.cgi?id=833033
which was originally committed upstream in commit
753ff83a50. That commit improperly
removed the "--except-interface lo" from dnsmasq commandlines when
--bind-dynamic was used (based on comments in the latter bug).
It turns out that the problem reported in the CVE could be eliminated
without removing "--except-interface lo", and removing it actually
caused each instance of dnsmasq to listen on localhost on port 53,
which created a new problem:
If another instance of dnsmasq using "bind-interfaces" (instead of
"bind-dynamic") had already been started (or if another instance
started later used "bind-dynamic"), this wouldn't have any immediately
visible ill effects, but if you tried to start another dnsmasq
instance using "bind-interfaces" *after* starting any libvirt
networks, the new dnsmasq would fail to start, because there was
already another process listening on port 53.
(Subsequent to the CVE fix, another patch changed the network driver
to put dnsmasq options in a conf file rather than directly on the
dnsmasq commandline, but preserved the same options.)
This patch changes the network driver to *always* add
"except-interface=lo" to dnsmasq conf files, regardless of whether we use
bind-dynamic or bind-interfaces. This way no libvirt dnsmasq instances
are listening on localhost (and the CVE is still fixed).
The actual code change is miniscule, but must be propogated through all
of the test files as well.
I noticed that /var/lib/libvirt/dnsmasq/*.conf used the wrong word;
it was intended to match the wording in src/util/xml.c.
* src/network/bridge_driver.c (networkDnsmasqConfContents): Fix typo.
* tests/networkxml2confdata/*.conf: Update accordingly.
This patch changes how parameters are passed to dnsmasq. Instead of
being on the command line, the parameters are put into a file (one
parameter per line) and a commandline --conf-file= specifies the
location of the file. The file is located in the same directory as
the leases file.
Putting the dnsmasq parameters into a configuration file
allows them to be examined and more easily understood than
examining the command lines displayed by "ps ax". This is
especially true when a number of networks have been started.
When the use of dnsmasq was originally done, the required command line
was simple, but it has gotten more complicated over time and will
likely become even more complicated in the future.
Note: The test conf files have all been renamed .conf instead of
.argv, and tests/networkxml2xmlargvdata was moved to
tests/networkxml2xmlconfdata.
