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Improve error handling

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This commit is contained in:
Xander Bil 2024-06-07 00:26:44 +02:00
parent 925370314a
commit 83fedebed6
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GPG key ID: EC9706B54A278598
4 changed files with 109 additions and 56 deletions
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18
src/db/models.rs
View file

@ -81,15 +81,15 @@ impl Record {
}
}
pub async fn insert_into_database(rr: RR) -> Result<(), DatabaseError> {
pub async fn insert_into_database(rr: &RR) -> Result<(), DatabaseError> {
let db_connection = &mut establish_connection();
let record = Record {
name: rr.name.join("."),
_type: rr._type.into(),
class: rr.class.into(),
_type: rr._type.clone().into(),
class: rr.class.clone().into(),
ttl: rr.ttl,
rdlength: rr.rdlength as i32,
rdata: rr.rdata,
rdata: rr.rdata.clone(),
};
Record::create(db_connection, record).map_err(|e| DatabaseError {
@ -128,11 +128,17 @@ pub async fn get_from_database(question: &Question) -> Result<Vec<RR>, DatabaseE
//TODO: cleanup models
pub async fn delete_from_database(
name: Vec<String>,
name: &Vec<String>,
_type: Option<Type>,
class: Class,
rdata: Option<Vec<u8>>,
) {
let db_connection = &mut establish_connection();
let _ = Record::delete(db_connection, name.join("."), _type.map(|f| f.into()), class.into(), rdata);
let _ = Record::delete(
db_connection,
name.join("."),
_type.map(|f| f.into()),
class.into(),
rdata,
);
}

18
src/errors.rs
View file

@ -1,8 +1,10 @@
use core::fmt;
#[derive(Debug)]
use crate::structs::RCODE;
pub struct DNSError {
pub message: String,
pub rcode: RCODE
}
impl fmt::Display for DNSError {
@ -25,7 +27,7 @@ impl fmt::Display for ParseError {
#[derive(Debug)]
pub struct DatabaseError {
pub message: String,
pub message: String
}
impl fmt::Display for DatabaseError {
@ -67,3 +69,15 @@ where
}
}
}
impl<E> From<E> for DNSError
where
E: Into<ParseError>,
{
fn from(value: E) -> Self {
DNSError {
message: value.into().to_string(),
rcode: RCODE::FORMERR
}
}
}

120
src/resolver.rs
View file

@ -6,7 +6,7 @@ use tokio::net::UdpSocket;
use crate::authenticate::authenticate;
use crate::db::models::{delete_from_database, get_from_database, insert_into_database};
use crate::errors::ParseError;
use crate::errors::{DNSError, ParseError};
use crate::parser::FromBytes;
use crate::reader::Reader;
use crate::sig::Sig;
@ -15,7 +15,7 @@ use crate::utils::vec_equal;
const MAX_DATAGRAM_SIZE: usize = 4096;
fn set_response_flags(flags: u16, rcode: RCODE) -> u16 {
fn set_response_flags(flags: &u16, rcode: RCODE) -> u16 {
(flags | 0b1_0000_1_0_0_0_000_0000 | rcode as u16) & 0b1_1111_1_0_1_0_111_1111
}
@ -23,46 +23,50 @@ fn get_opcode(flags: &u16) -> Result<Opcode, String> {
Opcode::try_from((flags & 0b0111100000000000) >> 11)
}
async fn handle_query(message: Message) -> Message {
async fn handle_query(message: &Message) -> Result<Message, DNSError> {
let mut response = message.clone();
response.header.arcount = 0; //TODO: fix this, handle unknown class values
for question in message.question {
for question in &message.question {
let answers = get_from_database(&question).await;
match answers {
Ok(rrs) => {
response.header.flags = set_response_flags(response.header.flags, RCODE::NOERROR);
response.header.ancount = rrs.len() as u16;
response.answer = rrs
response.answer.extend(rrs)
}
Err(e) => {
response.header.flags = set_response_flags(response.header.flags, RCODE::NXDOMAIN);
eprintln!("{}", e);
return Err(DNSError {
rcode: RCODE::NXDOMAIN,
message: e.to_string(),
})
}
}
}
response
Ok(response)
}
async fn handle_update(message: Message, bytes: &[u8]) -> Message {
let mut response = message.clone();
async fn handle_update(message: &Message, bytes: &[u8]) -> Result<Message, DNSError> {
let response = message.clone();
// Zone section (question) processing
if (message.header.qdcount != 1)
|| !matches!(message.question[0].qtype, Type::Type(RRType::SOA))
{
response.header.flags = set_response_flags(response.header.flags, RCODE::FORMERR);
return response;
return Err(DNSError {
message: "Qdcount not one".to_string(),
rcode: RCODE::FORMERR,
});
}
// Check Zone authority
let zone = &message.question[0];
let zlen = zone.qname.len();
if !(zlen >= 2 && zone.qname[zlen - 1] == "gent" && zone.qname[zlen - 2] == "zeus") {
response.header.flags = set_response_flags(response.header.flags, RCODE::NOTAUTH);
return response;
return Err(DNSError {
message: "Invalid zone".to_string(),
rcode: RCODE::NOTAUTH,
});
}
// Check Prerequisite TODO: implement this
@ -70,15 +74,19 @@ async fn handle_update(message: Message, bytes: &[u8]) -> Message {
//TODO: this code is ugly
let last = message.additional.last();
if last.is_some() && last.unwrap()._type == Type::Type(RRType::KEY) {
let sig = Sig::new(last.unwrap(), bytes);
let sig = Sig::new(last.unwrap(), bytes)?;
if !authenticate(&sig, &zone.qname).await.is_ok_and(|x| x) {
response.header.flags = set_response_flags(response.header.flags, RCODE::NOTAUTH);
return response;
return Err(DNSError {
message: "Unable to verify authentication".to_string(),
rcode: RCODE::NOTAUTH,
});
}
} else {
response.header.flags = set_response_flags(response.header.flags, RCODE::NOTAUTH);
return response;
return Err(DNSError {
message: "No KEY record at the end of request found".to_string(),
rcode: RCODE::NOTAUTH,
});
}
// Update Section Prescan
@ -87,8 +95,10 @@ async fn handle_update(message: Message, bytes: &[u8]) -> Message {
// Check if rr has same zone
if rlen < zlen || !(vec_equal(&zone.qname, &rr.name[rlen - zlen..])) {
response.header.flags = set_response_flags(response.header.flags, RCODE::NOTZONE);
return response;
return Err(DNSError {
message: "RR has different zone from Question".to_string(),
rcode: RCODE::NOTZONE,
});
}
if (rr.class == Class::Class(RRClass::ANY) && (rr.ttl != 0 || rr.rdlength != 0))
@ -100,43 +110,50 @@ async fn handle_update(message: Message, bytes: &[u8]) -> Message {
]
.contains(&rr.class)
{
response.header.flags = set_response_flags(response.header.flags, RCODE::FORMERR);
return response;
return Err(DNSError {
message: "RR has invalid rr,ttl or class".to_string(),
rcode: RCODE::FORMERR,
});
}
}
for rr in message.authority {
for rr in &message.authority {
if rr.class == zone.qclass {
let _ = insert_into_database(rr).await;
let _ = insert_into_database(&rr).await;
} else if rr.class == Class::Class(RRClass::ANY) {
if rr._type == Type::Type(RRType::ANY) {
if rr.name == zone.qname {
response.header.flags =
set_response_flags(response.header.flags, RCODE::NOTIMP);
return response;
return Err(DNSError {
message: "Not yet implemented".to_string(),
rcode: RCODE::NOTIMP,
});
} else {
delete_from_database(rr.name, None, Class::Class(RRClass::IN), None).await;
delete_from_database(&rr.name, None, Class::Class(RRClass::IN), None).await;
}
} else {
delete_from_database(rr.name, Some(rr._type), Class::Class(RRClass::IN), None)
.await;
delete_from_database(
&rr.name,
Some(rr._type.clone()),
Class::Class(RRClass::IN),
None,
)
.await;
}
} else if rr.class == Class::Class(RRClass::NONE) {
if rr._type == Type::Type(RRType::SOA) {
continue;
}
delete_from_database(
rr.name,
Some(rr._type),
&rr.name,
Some(rr._type.clone()),
Class::Class(RRClass::IN),
Some(rr.rdata),
Some(rr.rdata.clone()),
)
.await;
}
}
response.header.flags = set_response_flags(response.header.flags, RCODE::NOERROR);
response
Ok(response)
}
fn handle_parse_error(bytes: &[u8], err: ParseError) -> Message {
@ -155,7 +172,7 @@ fn handle_parse_error(bytes: &[u8], err: ParseError) -> Message {
header.ancount = 0;
header.nscount = 0;
header.arcount = 0;
header.flags = set_response_flags(header.flags, RCODE::FORMERR);
header.flags = set_response_flags(&header.flags, RCODE::FORMERR);
Message {
header,
@ -169,11 +186,26 @@ fn handle_parse_error(bytes: &[u8], err: ParseError) -> Message {
async fn get_response(bytes: &[u8]) -> Message {
let mut reader = Reader::new(bytes);
match Message::from_bytes(&mut reader) {
Ok(message) => match get_opcode(&message.header.flags) {
Ok(opcode) => match opcode {
Opcode::QUERY => handle_query(message).await,
Opcode::UPDATE => handle_update(message, bytes).await,
},
Ok(mut message) => match get_opcode(&message.header.flags) {
Ok(opcode) => {
let result = match opcode {
Opcode::QUERY => handle_query(&message).await,
Opcode::UPDATE => handle_update(&message, bytes).await,
};
match result {
Ok(mut response) => {
response.header.flags =
set_response_flags(&response.header.flags, RCODE::NOERROR);
response
}
Err(e) => {
eprintln!("{}", e.to_string());
message.header.flags = set_response_flags(&message.header.flags, e.rcode);
message
}
}
}
Err(_) => todo!(),
},
Err(err) => handle_parse_error(bytes, err),

9
src/sig.rs
View file

@ -1,6 +1,7 @@
use base64::prelude::*;
use crate::{
errors::ParseError,
parser::FromBytes,
reader::Reader,
structs::{KeyRData, RR},
@ -16,20 +17,20 @@ pub enum PublicKey {
}
impl Sig {
pub fn new(rr: &RR, datagram: &[u8]) -> Sig {
pub fn new(rr: &RR, datagram: &[u8]) -> Result<Sig, ParseError> {
let mut request = datagram[0..datagram.len() - 11 - rr.rdlength as usize].to_vec();
request[11] -= 1; // Decrease arcount
let mut reader = Reader::new(&rr.rdata);
let key_rdata = KeyRData::from_bytes(&mut reader).unwrap();
let key_rdata = KeyRData::from_bytes(&mut reader)?;
let mut raw_data = rr.rdata[0..rr.rdata.len() - key_rdata.signature.len()].to_vec();
raw_data.extend(request);
Sig {
Ok(Sig {
raw_data,
key_rdata,
}
})
}
fn verify_ed25519(&self, key: String) -> bool {