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Factor NSEC3 records logic to its own module

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This commit is contained in:
Christian Poveda 2024-06-14 13:49:31 -05:00 committed by Benjamin Fry
parent 5d078ab765
commit 9f8c19cb71
3 changed files with 137 additions and 114 deletions
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184
conformance/packages/conformance-tests/src/name_server/rfc5155.rs
View File

@ -1,105 +1,11 @@
use std::collections::BTreeMap;
use std::net::Ipv4Addr;
use dns_test::client::{Client, DigSettings, DigStatus};
use dns_test::name_server::NameServer;
use dns_test::nsec3::NSEC3Records;
use dns_test::record::{Record, RecordType, NSEC3};
use dns_test::{Network, Result, FQDN};
/// An NSEC3 RR is said to "match" a name if the owner name of the NSEC3 RR is the same as the
/// hashed owner name of that name.
fn find_match<'a>(name_hash: &str, records: &'a BTreeMap<String, NSEC3>) -> Option<&'a NSEC3> {
records.get(name_hash)
}
/// An NSEC3 RR is said to cover a name if the hash of the name or "next closer" name falls between
/// the owner name and the next hashed owner name of the NSEC3. In other words, if it proves the
/// nonexistence of the name, either directly or by proving the nonexistence of an ancestor of the
/// name.
fn find_cover<'a>(name_hash: &str, records: &'a BTreeMap<String, NSEC3>) -> Option<&'a NSEC3> {
let (hash, candidate) = records
// Find the greater hash that is less or equal than the name's hash.
.range(..=name_hash.to_owned())
.last()
// If no value is less or equal than the name's hash, it means that the name's hash is out
// of range and the last record covers it.
.or_else(|| records.last_key_value())?;
// If the found hash is exactly the name's hash, return None as it wouldn't be proving its
// nonexistence. Otherwise return the RR with that hash.
(hash != name_hash).then_some(candidate)
}
/// This proof consists of (up to) two different NSEC3 RRs:
/// - An NSEC3 RR that matches the closest (provable) encloser.
/// - An NSEC3 RR that covers the "next closer" name to the closest encloser.
fn closest_encloser_proof<'a>(
closest_encloser_hash: &str,
next_closer_name_hash: &str,
records: &'a BTreeMap<String, NSEC3>,
) -> Option<(&'a NSEC3, &'a NSEC3)> {
Some((
find_match(closest_encloser_hash, records)?,
find_cover(next_closer_name_hash, records)?,
))
}
fn query_nameserver(
records: impl IntoIterator<Item = Record>,
qname: &FQDN,
qtype: RecordType,
) -> Result<(BTreeMap<String, NSEC3>, DigStatus, Vec<NSEC3>)> {
let network = Network::new()?;
let mut ns = NameServer::new(&dns_test::SUBJECT, FQDN::ROOT, &network)?;
for record in records {
ns.add(record);
}
let ns = ns.sign()?;
// Extract the NSEC3 RRs from the signed zonefile and sort them by the hash embedded in the
// last label of each record's owner.
let nsec3_rrs = ns
.signed_zone_file()
.records
.iter()
.cloned()
.filter_map(|rr| {
let mut nsec3_rr = rr.try_into_nsec3().ok()?;
nsec3_rr.next_hashed_owner_name = nsec3_rr.next_hashed_owner_name.to_uppercase();
Some((nsec3_rr.fqdn.last_label().to_uppercase(), nsec3_rr))
})
.collect::<BTreeMap<_, _>>();
let ns = ns.start()?;
let client = Client::new(&network)?;
let output = client.dig(
*DigSettings::default().dnssec().authentic_data(),
ns.ipv4_addr(),
qtype,
qname,
)?;
let nsec3_rrs_response = output
.authority
.into_iter()
.filter_map(|rr| rr.try_into_nsec3().ok())
.collect::<Vec<_>>();
Ok((nsec3_rrs, output.status, nsec3_rrs_response))
}
#[track_caller]
fn find_records<'a>(
records: &[NSEC3],
records_and_err_msgs: impl IntoIterator<Item = (&'a NSEC3, &'a str)>,
) {
for (record, err_msg) in records_and_err_msgs {
records.iter().find(|&rr| rr == record).expect(err_msg);
}
}
const ALICE_FQDN: &str = "alice.com.";
const CHARLIE_FQDN: &str = "charlie.alice.com.";
const WILDCARD_FQDN: &str = "*.alice.com.";
@ -120,9 +26,7 @@ fn name_error_response() -> Result<()> {
let qname = FQDN(CHARLIE_FQDN)?;
let (nsec3_rrs, status, nsec3_rrs_response) = query_nameserver(
[
Record::a(alice_fqdn, Ipv4Addr::new(1, 2, 3, 4)),
],
[Record::a(alice_fqdn, Ipv4Addr::new(1, 2, 3, 4))],
&qname,
RecordType::A,
)?;
@ -139,9 +43,9 @@ fn name_error_response() -> Result<()> {
// this scenario, the closest encloser is `alice.com.` which means that the next closer name is `charlie.alice.com.`
// If this panics, it probably means that the precomputed hashes must be recomputed.
let (closest_encloser_rr, next_closer_name_rr) =
closest_encloser_proof(ALICE_HASH, CHARLIE_HASH, &nsec3_rrs)
.expect("Cannot find a closest encloser proof in the zonefile");
let (closest_encloser_rr, next_closer_name_rr) = nsec3_rrs
.closest_encloser_proof(ALICE_HASH, CHARLIE_HASH)
.expect("Cannot find a closest encloser proof in the zonefile");
// Wildcard at the closet encloser RR: Must cover the wildcard at the closest encloser of
// QNAME.
@ -152,8 +56,9 @@ fn name_error_response() -> Result<()> {
// This NSEC3 RR must cover the hash of the wildcard at the closests encloser.
// if this panics, it probably means that the precomputed hashes must be recomputed.
let wildcard_rr =
find_cover(WILDCARD_HASH, &nsec3_rrs).expect("No RR in the zonefile covers the wildcard");
let wildcard_rr = nsec3_rrs
.find_cover(WILDCARD_HASH)
.expect("No RR in the zonefile covers the wildcard");
// Now we check that the response has the three NSEC3 RRs.
find_records(
@ -192,7 +97,9 @@ fn no_data_response_not_ds() -> Result<()> {
// The server MUST include the NSEC3 RR that matches QNAME.
// if this panics, it probably means that the precomputed hashes must be recomputed.
let qname_rr = find_match(ALICE_HASH, &nsec3_rrs).expect("No RR in the zonefile matches QNAME");
let qname_rr = nsec3_rrs
.find_match(ALICE_HASH)
.expect("No RR in the zonefile matches QNAME");
find_records(
&nsec3_rrs_response,
@ -220,7 +127,9 @@ fn no_data_response_ds_match() -> Result<()> {
// If there is an NSEC3 RR that matches QNAME, the server MUST return it in the response.
// if this panics, it probably means that the precomputed hashes must be recomputed.
let qname_rr = find_match(ALICE_HASH, &nsec3_rrs).expect("No RR in the zonefile matches QNAME");
let qname_rr = nsec3_rrs
.find_match(ALICE_HASH)
.expect("No RR in the zonefile matches QNAME");
find_records(
&nsec3_rrs_response,
@ -258,9 +167,9 @@ fn no_data_response_ds_no_match() -> Result<()> {
// this scenario, the closest encloser is `alice.com.` which means that the next closer name is `charlie.alice.com.`
// If this panics, it probably means that the precomputed hashes must be recomputed.
let (closest_encloser_rr, next_closer_name_rr) =
closest_encloser_proof(ALICE_HASH, CHARLIE_HASH, &nsec3_rrs)
.expect("Cannot find a closest encloser proof in the zonefile");
let (closest_encloser_rr, next_closer_name_rr) = nsec3_rrs
.closest_encloser_proof(ALICE_HASH, CHARLIE_HASH)
.expect("Cannot find a closest encloser proof in the zonefile");
find_records(
&nsec3_rrs_response,
@ -307,15 +216,16 @@ fn wildcard_no_data_response() -> Result<()> {
// this scenario, the closest encloser is `alice.com.` which means that the next closer name is `charlie.alice.com.`
// If this panics, it probably means that the precomputed hashes must be recomputed.
let (closest_encloser_rr, next_closer_name_rr) =
closest_encloser_proof(ALICE_HASH, CHARLIE_HASH, &nsec3_rrs)
.expect("Cannot find a closest encloser proof in the zonefile");
let (closest_encloser_rr, next_closer_name_rr) = nsec3_rrs
.closest_encloser_proof(ALICE_HASH, CHARLIE_HASH)
.expect("Cannot find a closest encloser proof in the zonefile");
// Wildcard RR: This NSEC3 RR must match `*.alice.com`.
// If this panics, it probably means that the precomputed hashes must be recomputed.
let wildcard_rr =
find_match(WILDCARD_HASH, &nsec3_rrs).expect("No RR in the zonefile matches the wildcard");
let wildcard_rr = nsec3_rrs
.find_match(WILDCARD_HASH)
.expect("No RR in the zonefile matches the wildcard");
find_records(
&nsec3_rrs_response,
@ -358,7 +268,8 @@ fn wildcard_answer_response() -> Result<()> {
// this scenario, the closest encloser is `alice.com.` which means that the next closer name is `charlie.alice.com.`
// If this panics, it probably means that the precomputed hashes must be recomputed.
let next_closer_name_rr = find_cover(CHARLIE_HASH, &nsec3_rrs)
let next_closer_name_rr = nsec3_rrs
.find_cover(CHARLIE_HASH)
.expect("No RR in the zonefile covers the next closer name");
find_records(
@ -371,3 +282,48 @@ fn wildcard_answer_response() -> Result<()> {
Ok(())
}
fn query_nameserver(
records: impl IntoIterator<Item = Record>,
qname: &FQDN,
qtype: RecordType,
) -> Result<(NSEC3Records, DigStatus, Vec<NSEC3>)> {
let network = Network::new()?;
let mut ns = NameServer::new(&dns_test::SUBJECT, FQDN::ROOT, &network)?;
for record in records {
ns.add(record);
}
let ns = ns.sign()?;
let nsec3_rrs = NSEC3Records::new(ns.signed_zone_file());
let ns = ns.start()?;
let client = Client::new(&network)?;
let output = client.dig(
*DigSettings::default().dnssec().authentic_data(),
ns.ipv4_addr(),
qtype,
qname,
)?;
let nsec3_rrs_response = output
.authority
.into_iter()
.filter_map(|rr| rr.try_into_nsec3().ok())
.collect::<Vec<_>>();
Ok((nsec3_rrs, output.status, nsec3_rrs_response))
}
#[track_caller]
fn find_records<'a>(
records: &[NSEC3],
records_and_err_msgs: impl IntoIterator<Item = (&'a NSEC3, &'a str)>,
) {
for (record, err_msg) in records_and_err_msgs {
records.iter().find(|&rr| rr == record).expect(err_msg);
}
}

1
conformance/packages/dns-test/src/lib.rs
View File

@ -15,6 +15,7 @@ mod container;
mod fqdn;
mod implementation;
pub mod name_server;
pub mod nsec3;
pub mod record;
mod resolver;
mod trust_anchor;

66
conformance/packages/dns-test/src/nsec3.rs Normal file
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@ -0,0 +1,66 @@
use std::collections::BTreeMap;
use crate::{record::NSEC3, zone_file::ZoneFile};
pub struct NSEC3Records {
records: BTreeMap<String, NSEC3>,
}
impl NSEC3Records {
/// Extract the NSEC3 RRs from the signed zonefile and sort them by the hash embedded in the
/// last label of each record's owner.
pub fn new(signed_zf: &ZoneFile) -> Self {
Self {
records: signed_zf
.records
.iter()
.cloned()
.filter_map(|rr| {
let mut nsec3_rr = rr.try_into_nsec3().ok()?;
nsec3_rr.next_hashed_owner_name =
nsec3_rr.next_hashed_owner_name.to_uppercase();
Some((nsec3_rr.fqdn.last_label().to_uppercase(), nsec3_rr))
})
.collect(),
}
}
/// An NSEC3 RR is said to "match" a name if the owner name of the NSEC3 RR is the same as the
/// hashed owner name of that name.
pub fn find_match<'a>(&'a self, name_hash: &str) -> Option<&'a NSEC3> {
self.records.get(name_hash)
}
/// An NSEC3 RR is said to cover a name if the hash of the name or "next closer" name falls between
/// the owner name and the next hashed owner name of the NSEC3. In other words, if it proves the
/// nonexistence of the name, either directly or by proving the nonexistence of an ancestor of the
/// name.
pub fn find_cover<'a>(&'a self, name_hash: &str) -> Option<&'a NSEC3> {
let (hash, candidate) = self
.records
// Find the greater hash that is less or equal than the name's hash.
.range(..=name_hash.to_owned())
.last()
// If no value is less or equal than the name's hash, it means that the name's hash is out
// of range and the last record covers it.
.or_else(|| self.records.last_key_value())?;
// If the found hash is exactly the name's hash, return None as it wouldn't be proving its
// nonexistence. Otherwise return the RR with that hash.
(hash != name_hash).then_some(candidate)
}
/// This proof consists of (up to) two different NSEC3 RRs:
/// - An NSEC3 RR that matches the closest (provable) encloser.
/// - An NSEC3 RR that covers the "next closer" name to the closest encloser.
pub fn closest_encloser_proof<'a>(
&'a self,
closest_encloser_hash: &str,
next_closer_name_hash: &str,
) -> Option<(&'a NSEC3, &'a NSEC3)> {
Some((
self.find_match(closest_encloser_hash)?,
self.find_cover(next_closer_name_hash)?,
))
}
}