I got reported bug in Fedora [1], that cname is broken in new releases.
At first I though this was false report, but there is still new
regression in cname handling.
Before, it accepted alias with trailing dot. Not it would accept only
target, but not alias.
cname=alias.,target
is no longer valid. The issue is it will count size to skip after
canonicalize. If that ignores trailing dot, next name would be "". And
that is invalid and refused, dnsmasq refuses to start.
I also think that any whitespace like tab should be possible after
comma. So this fixes also 30858e3b9b.
The way of accessing the list of available hashes on nettle was
vulnerable to breaking if the version of libnettle in use was
different to the version dnsmasq was compiled against.
Change to a new system if libnettle >= 3.4 is in use.
Older versions if nettle are still OK, once 3.4 is reached,
the ABi problem is fixed. Thanks to Petr Menšík for clues on this.
Use strlen to determine the length of the filename returned by
inotify, as in->len refers to the length of the buffer containing
the name, not the length of the name itself.
http://lists.thekelleys.org.uk/pipermail/dnsmasq-discuss/2018q1/011950.html
Signed-off-by: Andy Hawkins <andy@gently.org.uk>
Patch further modified by simon@thekelleys.org to avoid
out-of-bounds array access with an empty string, call strlen once,
and reverse order of filename verifcation and resolv-file test.
It's OK for NSEC records to be expanded from wildcards,
but in that case, the proof of non-existence is only valid
starting at the wildcard name, *.<domain> NOT the name expanded
from the wildcard. Without this check it's possible for an
attacker to craft an NSEC which wrongly proves non-existence
in a domain which includes a wildcard for NSEC.
RFC 4034 says:
[RFC2181] specifies that an RRset is not allowed to contain duplicate
records (multiple RRs with the same owner name, class, type, and
RDATA). Therefore, if an implementation detects duplicate RRs when
putting the RRset in canonical form, it MUST treat this as a protocol
error. If the implementation chooses to handle this protocol error
in the spirit of the robustness principle (being liberal in what it
accepts), it MUST remove all but one of the duplicate RR(s) for the
purposes of calculating the canonical form of the RRset.
We chose to handle this robustly, having found at least one recursive
server in the wild which returns duplicate NSEC records in the AUTHORITY
section of an answer generated from a wildcard record. sort_rrset() is
therefore modified to delete duplicate RRs which are detected almost
for free during the bubble-sort process.
Thanks to Toralf Förster for helping to diagnose this problem.
If all configured dns servers return refused in
response to a query; dnsmasq will end up in an infinite loop
retransmitting the dns query resulting into high CPU load.
Problem is caused by the dns refuse retransmission logic which does
not check for the end of a dns server list iteration in strict mode.
Having one configured dns server returning a refused reply easily
triggers this problem in strict order mode. This was introduced in
9396752c11
Thanks to Hans Dedecker <dedeckeh@gmail.com> for spotting this
and the initial patch.
Simon Kelley