Ubuntu: USN-3430-3: Dnsmasq regression

USN-3430-2 fixed several vulnerabilities. The update introduced a new regression that breaks DNS resolution. This update addresses the problem.

We apologize for the inconvenience.

Original advisory details:

Felix Wilhelm, Fermin J. Serna, Gabriel Campana and Kevin Hamacher discovered that Dnsmasq incorrectly handled DNS requests. A remote attacker could use this issue to cause Dnsmasq to crash, resulting in a denial of service, or possibly execute arbitrary code. (CVE-2017-14491) Felix Wilhelm, Fermin J. Serna, Gabriel Campana and Kevin Hamacher discovered that Dnsmasq incorrectly handled IPv6 router advertisements. A remote attacker could use this issue to cause Dnsmasq to crash, resulting in a denial of service, or possibly execute arbitrary code. (CVE-2017-14492) Felix Wilhelm, Fermin J. Serna, Gabriel Campana and Kevin Hamacher discovered that Dnsmasq incorrectly handled DHCPv6 requests. A remote attacker could use this issue to cause Dnsmasq to crash, resulting in a denial of service, or possibly execute arbitrary code. (CVE-2017-14493) Felix Wilhelm, Fermin J. Serna, Gabriel Campana and Kevin Hamacher discovered that Dnsmasq incorrectly handled DHCPv6 packets. A remote attacker could use this issue to possibly obtain sensitive memory contents. (CVE-2017-14494) Felix Wilhelm, Fermin J. Serna, Gabriel Campana and Kevin Hamacher discovered that Dnsmasq incorrectly handled DNS requests. A remote attacker could use this issue to cause Dnsmasq to consume memory, resulting in a denial of service. (CVE-2017-14495) Felix Wilhelm, Fermin J. Serna, Gabriel Campana and Kevin Hamacher discovered that Dnsmasq incorrectly handled DNS requests. A remote attacker could use this issue to cause Dnsmasq to crash, resulting in a denial of service. (CVE-2017-14496)