From 9d6d40ea01a504e3938079078b8e98b8a9e9faf8 Mon Sep 17 00:00:00 2001
From: Alonso <alonso.herrera@ug.uchile.cl>
Date: Thu, 11 Jul 2024 22:04:45 -0400
Subject: [PATCH] feat: added dnssec module

---
 src/dnssec/dnssec.rs | 60 ++++++++++++++++++++++++++++++++++++++++++++
 1 file changed, 60 insertions(+)
 create mode 100644 src/dnssec/dnssec.rs

diff --git a/src/dnssec/dnssec.rs b/src/dnssec/dnssec.rs
new file mode 100644
index 00000000..fb49a618
--- /dev/null
+++ b/src/dnssec/dnssec.rs
@@ -0,0 +1,60 @@
+// src/dnssec.rs
+
+pub mod dnssec {
+    use super::message::{DnskeyRdata, RrsigRdata, DsRdata, DnsMessage, DnsError};
+    use sha2::{Sha256, Sha512, Digest};
+    use hmac::{Hmac, Mac, NewMac};
+    use rust_crypto::rsa::{RSAPublicKey, RSAVerify};
+    use base64::decode;
+
+    pub fn fetch_dnskey_records(domain: &str) -> Result<Vec<DnskeyRdata>, DnsError> {
+        // Completar
+        Ok(vec![DnskeyRdata::new(256, 3, 8, vec![0x03, 0x01, 0x00, 0x01])])
+    }
+
+    pub fn verify_rrsig_signature(
+        rrsig: &RrsigRdata,
+        dnskey: &DnskeyRdata,
+        signed_data: &[u8]
+    ) -> Result<bool, DnsError> {
+        rsa_verify(&dnskey.public_key, &rrsig.signature, signed_data)
+    }
+
+    pub fn verify_ds_record(
+        ds: &DsRdata,
+        dnskey: &DnskeyRdata
+    ) -> Result<bool, DnsError> {
+        let digest = compute_digest(ds.algorithm, &dnskey.to_bytes())?;
+        Ok(digest == ds.digest)
+    }
+
+    fn rsa_verify(
+        public_key: &[u8],
+        signature: &[u8],
+        signed_data: &[u8]
+    ) -> Result<bool, DnsError> {
+        let public_key = RSAPublicKey::from_der(public_key).map_err(|_| DnsError::VerificationFailed)?;
+        public_key.verify(signature, signed_data).map_err(|_| DnsError::VerificationFailed)?;
+
+        Ok(true)
+    }
+
+    fn compute_digest(
+        algorithm: u8,
+        data: &[u8]
+    ) -> Result<Vec<u8>, DnsError> {
+        match algorithm {
+            1 => {
+                let mut hasher = Sha256::new();
+                hasher.update(data);
+                Ok(hasher.finalize().to_vec())
+            },
+            2 => {
+                let mut hasher = Sha512::new();
+                hasher.update(data);
+                Ok(hasher.finalize().to_vec())
+            },
+            _ => Err(DnsError::UnsupportedAlgorithm),
+        }
+    }
+}