- Update to 2.83:
* bsc#1177077: Fixed DNSpooq vulnerabilities
* Use the values of --min-port and --max-port in outgoing
TCP connections to upstream DNS servers.
* Fix a remote buffer overflow problem in the DNSSEC code.
Any dnsmasq with DNSSEC compiled in and enabled is vulnerable
to this, referenced by CVE-2020-25681, CVE-2020-25682,
CVE-2020-25683 CVE-2020-25687.
* Be sure to only accept UDP DNS query replies at the address
from which the query was originated. This keeps as much
entropy in the {query-ID, random-port} tuple as possible, to
help defeat cache poisoning attacks. Refer: CVE-2020-25684.
* Use the SHA-256 hash function to verify that DNS answers
received are for the questions originally asked. This replaces
the slightly insecure SHA-1 (when compiled with DNSSEC) or
the very insecure CRC32 (otherwise). Refer: CVE-2020-25685
* Handle multiple identical near simultaneous DNS queries better.
Previously, such queries would all be forwarded independently.
This is, in theory, inefficent but in practise not a problem,
_except_ that is means that an answer for any of the forwarded
queries will be accepted and cached.
An attacker can send a query multiple times, and for each
repeat, another {port, ID} becomes capable of accepting the
answer he is sending in the blind, to random IDs and ports.
The chance of a succesful attack is therefore multiplied by the
number of repeats of the query. The new behaviour detects
repeated queries and merely stores the clients sending repeats
so that when the first query completes, the answer can be sent
to all the clients who asked. Refer: CVE-2020-25686.