From 3f6d0340fc44f8ca3302ad2216437d85f04b7734 Mon Sep 17 00:00:00 2001
From: Matt Corallo <git@bluematt.me>
Date: Tue, 6 Feb 2024 05:45:51 +0000
Subject: [PATCH] Correct proof building for records at a zone root

---
 src/query.rs | 64 +++++++++++++++++++++-------------------------------
 1 file changed, 26 insertions(+), 38 deletions(-)

diff --git a/src/query.rs b/src/query.rs
index 8ce5519..967c840 100644
--- a/src/query.rs
+++ b/src/query.rs
@@ -107,55 +107,43 @@ async fn read_response_async(stream: &mut TokioTcpStream, proof: &mut Vec<u8>) -
 	handle_response(&resp, proof)
 }
 
-fn build_proof(resolver: SocketAddr, domain: Name, ty: u16) -> Result<Vec<u8>, Error> {
-	let mut stream = TcpStream::connect(resolver)?;
-	let mut res = Vec::new();
-	send_query(&mut stream, domain, ty)?;
-	let mut reached_root = false;
-	for _ in 0..10 {
-		let rrsig_opt = read_response(&mut stream, &mut res)?;
-		if let Some(rrsig) = rrsig_opt {
-			if rrsig.name.as_str() == "." {
-				reached_root = true;
-			} else {
-				if rrsig.name == rrsig.key_name {
-					send_query(&mut stream, rrsig.key_name, DS::TYPE)?;
+macro_rules! build_proof_impl {
+	($stream: ident, $send_query: ident, $read_response: ident $(, $async_ok: tt)?) => { {
+		let mut res = Vec::new();
+		let mut reached_root = false;
+		for i in 0..10 {
+			let rrsig_opt = $read_response(&mut $stream, &mut res)
+				$(.await?; $async_ok)??; // Either await?; Ok(())?, or just ?
+			if let Some(rrsig) = rrsig_opt {
+				if rrsig.name.as_str() == "." {
+					reached_root = true;
 				} else {
-					send_query(&mut stream, rrsig.key_name, DnsKey::TYPE)?;
+					if i != 0 && rrsig.name == rrsig.key_name {
+						$send_query(&mut $stream, rrsig.key_name, DS::TYPE)
+					} else {
+						$send_query(&mut $stream, rrsig.key_name, DnsKey::TYPE)
+					}$(.await?; $async_ok)??; // Either await?; Ok(())?, or just ?
 				}
 			}
+			if reached_root { break; }
 		}
-		if reached_root { break; }
-	}
 
-	if !reached_root { Err(Error::new(ErrorKind::Other, "Too many requests required")) }
-	else { Ok(res) }
+		if !reached_root { Err(Error::new(ErrorKind::Other, "Too many requests required")) }
+		else { Ok(res) }
+	} }
+}
+
+fn build_proof(resolver: SocketAddr, domain: Name, ty: u16) -> Result<Vec<u8>, Error> {
+	let mut stream = TcpStream::connect(resolver)?;
+	send_query(&mut stream, domain, ty)?;
+	build_proof_impl!(stream, send_query, read_response)
 }
 
 #[cfg(feature = "tokio")]
 async fn build_proof_async(resolver: SocketAddr, domain: Name, ty: u16) -> Result<Vec<u8>, Error> {
 	let mut stream = TokioTcpStream::connect(resolver).await?;
-	let mut res = Vec::new();
 	send_query_async(&mut stream, domain, ty).await?;
-	let mut reached_root = false;
-	for _ in 0..10 {
-		let rrsig_opt = read_response_async(&mut stream, &mut res).await?;
-		if let Some(rrsig) = rrsig_opt {
-			if rrsig.name.as_str() == "." {
-				reached_root = true;
-			} else {
-				if rrsig.name == rrsig.key_name {
-					send_query_async(&mut stream, rrsig.key_name, DS::TYPE).await?;
-				} else {
-					send_query_async(&mut stream, rrsig.key_name, DnsKey::TYPE).await?;
-				}
-			}
-		}
-		if reached_root { break; }
-	}
-
-	if !reached_root { Err(Error::new(ErrorKind::Other, "Too many requests required")) }
-	else { Ok(res) }
+	build_proof_impl!(stream, send_query_async, read_response_async, { Ok::<(), Error>(()) })
 }
 
 /// Builds a DNSSEC proof for an A record by querying a recursive resolver
-- 
2.39.5