Fix multiple vulnerabilities in the resolver

This fixes some vulnerabilities in the resolver that make spoofing DNS
queries somewhat trivial due to the code failing to randomize xid, as
well as match the reply xid with the query, and the origin of the packet:

 - xid of the query was fixed at zero
 - xid from the reply was never checked
 - source address of the reply was never checked

This means anyone can flood the host with a fake reply with xid 0,
guessing the source port is trivial as it's less than 16bits (2^16 -
1024), which would cause odin to resolve a hostname to whatever an
attacker wanted.

While here also plug in two memory leaks.

Since this is CVE material, I've contacted @kelimion before hand which
instructed to put it in a PR.

There are also more bugs as the code conflates answer section,
authority section and aditional section into one, while in reality
only the anwer section should be taken into consideration.

0 files changed, 0 insertions, 0 deletions