use std::collections::BTreeMap; use base64::Engine; use openssl::{hash::MessageDigest, pkey::PKey, sign::Verifier}; #[derive(Debug, thiserror::Error)] pub enum HttpSignatureError { #[error("openssl error: {0:?}")] OpenSSL(#[from] openssl::error::ErrorStack), #[error("invalid UTF8 in key: {0:?}")] UTF8(#[from] std::str::Utf8Error), #[error("os I/O error: {0}")] IO(#[from] std::io::Error), #[error("invalid base64: {0}")] Base64(#[from] base64::DecodeError), } pub fn digest(data: &str) -> String { format!("sha-256={}", base64::prelude::BASE64_STANDARD.encode( openssl::sha::sha256(data.as_bytes()) ) ) } #[derive(Debug, Clone, Default)] pub struct HttpSignature { pub key_id: String, pub algorithm: String, pub headers: Vec, pub signature: String, pub control: String, } impl HttpSignature { pub fn new(key_id: String, algorithm: String, headers: &[&str]) -> Self { HttpSignature { key_id, algorithm, headers: headers.iter().map(|x| x.to_string()).collect(), signature: String::new(), control: String::new(), } } pub fn parse(header: &str) -> Self { let mut sig = HttpSignature::default(); header.split(',') .filter_map(|x| x.split_once('=')) .map(|(k, v)| (k, v.trim_end_matches('"').trim_matches('"'))) .for_each(|(k, v)| match k { "keyId" => sig.key_id = v.to_string(), "algorithm" => sig.algorithm = v.to_string(), "signature" => sig.signature = v.to_string(), "headers" => sig.headers = v.split(' ').map(|x| x.to_string()).collect(), _ => tracing::warn!("unexpected field in http signature: '{k}=\"{v}\"'"), }); sig } pub fn header(&self) -> String { format!( "keyId=\"{}\",algorithm=\"{}\",headers=\"{}\",signature=\"{}\"", self.key_id, self.algorithm, self.headers.join(" "), self.signature, ) } pub fn build_manually(&mut self, method: &str, target: &str, mut headers: BTreeMap) -> &mut Self { let mut out = Vec::new(); for header in &self.headers { match header.as_str() { "(request-target)" => out.push(format!("(request-target): {method} {target}")), // TODO other pseudo-headers _ => out.push( format!("{header}: {}", headers.remove(header).unwrap_or_default()) ), } } self.control = out.join("\n"); self } #[cfg(feature = "axum")] pub fn build_from_parts(&mut self, parts: &axum::http::request::Parts) -> &mut Self { let mut out = Vec::new(); for header in self.headers.iter() { match header.as_str() { "(request-target)" => out.push( format!( "(request-target): {} {}", parts.method.to_string().to_lowercase(), parts.uri.path_and_query().map(|x| x.as_str()).unwrap_or("/") ) ), // TODO other pseudo-headers, _ => out.push(format!("{}: {}", header.to_lowercase(), parts.headers.get(header).map(|x| x.to_str().unwrap_or("")).unwrap_or("") )), } } self.control = out.join("\n"); self } pub fn verify(&self, key: &str) -> Result { let pubkey = PKey::public_key_from_pem(key.as_bytes())?; let mut verifier = Verifier::new(MessageDigest::sha256(), &pubkey)?; let signature = base64::prelude::BASE64_STANDARD.decode(&self.signature)?; Ok(verifier.verify_oneshot(&signature, self.control.as_bytes())?) } pub fn sign(&mut self, key: &str) -> Result<&str, HttpSignatureError> { let privkey = PKey::private_key_from_pem(key.as_bytes())?; let mut signer = openssl::sign::Signer::new(MessageDigest::sha256(), &privkey)?; signer.update(self.control.as_bytes())?; self.signature = base64::prelude::BASE64_STANDARD.encode(signer.sign_to_vec()?); Ok(&self.signature) } } #[cfg(test)] mod test { // TODO more tests!!! #[test] fn http_signature_signs_and_verifies() { let key = openssl::rsa::Rsa::generate(2048).unwrap(); let private_key = std::str::from_utf8(&key.private_key_to_pem().unwrap()).unwrap().to_string(); let public_key = std::str::from_utf8(&key.public_key_to_pem().unwrap()).unwrap().to_string(); let mut signer = super::HttpSignature { key_id: "test".to_string(), algorithm: "rsa-sha256".to_string(), headers: vec![ "(request-target)".to_string(), "host".to_string(), "date".to_string(), ], signature: String::new(), control: String::new(), }; signer .build_manually("get", "/actor/inbox", [("host".into(), "example.net".into()), ("date".into(), "Sat, 13 Apr 2024 13:36:23 GMT".into())].into()) .sign(&private_key) .unwrap(); let mut verifier = super::HttpSignature::parse(&signer.header()); verifier.build_manually("get", "/actor/inbox", [("host".into(), "example.net".into()), ("date".into(), "Sat, 13 Apr 2024 13:36:23 GMT".into())].into()); assert!(verifier.verify(&public_key).unwrap()); } }