Add experimental extractor library for actix-web

Cargo.toml

@@ -13,10 +13,11 @@ edition = "2021"
 
 [workspace]
 members = [
-    "http-signature-normalization-actix",
-    "http-signature-normalization-http",
-    "http-signature-normalization-reqwest",
-    # "http-signature-normalization-warp",
+  "http-signature-normalization-actix",
+  "http-signature-normalization-actix-extractor",
+  "http-signature-normalization-http",
+  "http-signature-normalization-reqwest",
+  # "http-signature-normalization-warp",
 ]
 
 [dependencies]

http-signature-normalization-actix-extractor/Cargo.toml

@@ -0,0 +1,22 @@
+[package]
+name = "http-signature-normalization-actix-extractor"
+version = "0.1.0"
+edition = "2021"
+
+# See more keys and their definitions at https://doc.rust-lang.org/cargo/reference/manifest.html
+[features]
+default = ["sha-2"]
+sha-2 = ["base64", "sha2", "subtle"]
+
+[dependencies]
+base64 = { version = "0.13", optional = true }
+actix-web = { version = "4", default-features = false }
+actix-web-lab = "0.18.5"
+async-trait = "0.1.58"
+http-signature-normalization = { version = "0.6", path = "../" }
+sha2 = { version = "0.10", optional = true }
+subtle = { version = "2.4.1", optional = true }
+
+[dev-dependencies]
+actix-web = { version = "4", features = ["macros"] }
+thiserror = "1"

http-signature-normalization-actix-extractor/examples/server.rs

@@ -0,0 +1,88 @@
+use actix_web::{http::StatusCode, web, App, HttpRequest, HttpResponse, HttpServer, ResponseError};
+use http_signature_normalization_actix_extractor::{
+    Algorithm, Config, ConfigGenerator, PrivateKey, Signed,
+};
+use sha2::Sha256;
+
+#[actix_web::main]
+async fn main() -> std::io::Result<()> {
+    HttpServer::new(|| App::new().route("/", web::post().to(protected)))
+        .bind("127.0.0.1:8010")?
+        .run()
+        .await
+}
+
+async fn protected(signed_request: Signed<String, Cfg, Sha256, Key>) -> &'static str {
+    let (value, signature) = signed_request.into_parts();
+
+    println!("{}", value);
+    println!("{:#?}", signature);
+
+    "hewwo, mr obama"
+}
+
+pub struct Cfg;
+
+impl ConfigGenerator for Cfg {
+    fn config() -> Config {
+        Config::new().require_header("accept")
+    }
+}
+
+#[derive(Debug)]
+pub struct Key;
+
+#[async_trait::async_trait(?Send)]
+impl PrivateKey for Key {
+    type Error = MyError;
+
+    async fn init(
+        _: &HttpRequest,
+        key_id: &str,
+        algorithm: Option<&Algorithm>,
+    ) -> Result<Self, Self::Error> {
+        match algorithm {
+            Some(Algorithm::Hs2019) => (),
+            _ => return Err(MyError::Algorithm),
+        };
+
+        if key_id != "my-key-id" {
+            return Err(MyError::Key);
+        }
+
+        Ok(Key)
+    }
+
+    fn verify(&mut self, signature: &str, signing_string: &str) -> Result<bool, Self::Error> {
+        use subtle::ConstantTimeEq;
+
+        let decoded = match base64::decode(&signature) {
+            Ok(decoded) => decoded,
+            Err(_) => return Err(MyError::Decode),
+        };
+
+        Ok(decoded.ct_eq(signing_string.as_bytes()).into())
+    }
+}
+
+#[derive(Debug, thiserror::Error)]
+pub enum MyError {
+    #[error("Unsupported algorithm")]
+    Algorithm,
+
+    #[error("Couldn't decode signature")]
+    Decode,
+
+    #[error("Invalid key")]
+    Key,
+}
+
+impl ResponseError for MyError {
+    fn status_code(&self) -> StatusCode {
+        StatusCode::BAD_REQUEST
+    }
+
+    fn error_response(&self) -> HttpResponse {
+        HttpResponse::BadRequest().finish()
+    }
+}

http-signature-normalization-actix-extractor/src/lib.rs

@@ -0,0 +1,286 @@
+// #![deny(missing_docs)]
+
+//! Experimental Extractor for request signatures
+
+pub use actix_web_lab::extract::RequestSignature;
+pub use http_signature_normalization::{verify::Algorithm, Config};
+
+pub type Signed<Extractor, Config, Digest, PrivateKey> =
+    RequestSignature<Extractor, SignatureScheme<Config, Digest, PrivateKey>>;
+
+#[cfg(feature = "sha-2")]
+mod sha2_digest;
+
+#[derive(Debug)]
+pub enum Error {
+    Digest,
+    Signature,
+    InvalidHeaderValue,
+    PrepareVerify(http_signature_normalization::PrepareVerifyError),
+}
+
+impl std::fmt::Display for Error {
+    fn fmt(&self, f: &mut std::fmt::Formatter<'_>) -> std::fmt::Result {
+        match self {
+            Self::Digest => write!(f, "Digest is inavlid"),
+            Self::Signature => write!(f, "Signature is invalid"),
+            Self::InvalidHeaderValue => write!(f, "Invalid header value"),
+            Self::PrepareVerify(_) => write!(f, "Error preparint verification"),
+        }
+    }
+}
+
+impl std::error::Error for Error {
+    fn source(&self) -> Option<&(dyn std::error::Error + 'static)> {
+        match self {
+            Self::PrepareVerify(ref e) => Some(e),
+            Self::Digest => None,
+            Self::Signature => None,
+            Self::InvalidHeaderValue => None,
+        }
+    }
+}
+
+impl actix_web::ResponseError for Error {
+    fn status_code(&self) -> actix_web::http::StatusCode {
+        actix_web::http::StatusCode::BAD_REQUEST
+    }
+
+    fn error_response(&self) -> actix_web::HttpResponse<actix_web::body::BoxBody> {
+        actix_web::HttpResponse::build(self.status_code()).finish()
+    }
+}
+
+impl From<http_signature_normalization::PrepareVerifyError> for Error {
+    fn from(e: http_signature_normalization::PrepareVerifyError) -> Self {
+        Error::PrepareVerify(e)
+    }
+}
+
+impl From<actix_web::http::header::ToStrError> for Error {
+    fn from(_: actix_web::http::header::ToStrError) -> Self {
+        Error::InvalidHeaderValue
+    }
+}
+
+pub struct SignatureScheme<C, D, K> {
+    config_generator: std::marker::PhantomData<C>,
+    key: std::marker::PhantomData<K>,
+    digest_verifier: Option<D>,
+    unverified: http_signature_normalization::verify::Unverified,
+}
+
+#[derive(Debug)]
+pub struct DigestPart {
+    pub algorithm: String,
+    pub digest: String,
+}
+
+#[derive(Debug)]
+pub struct Signature<D, K> {
+    key: K,
+    unverified: http_signature_normalization::verify::Unverified,
+    digest_verifier: D,
+    digest_parts: Option<Vec<DigestPart>>,
+}
+
+pub trait DigestName {
+    const NAME: &'static str;
+}
+
+pub trait ConfigGenerator {
+    fn config() -> Config;
+}
+
+#[async_trait::async_trait(?Send)]
+pub trait PrivateKey: Sized + Send {
+    type Error: Into<actix_web::Error>;
+
+    async fn init(
+        req: &actix_web::HttpRequest,
+        key_id: &str,
+        algorithm: Option<&Algorithm>,
+    ) -> Result<Self, Self::Error>;
+
+    fn verify(&mut self, signature: &str, signing_string: &str) -> Result<bool, Self::Error>;
+}
+
+pub trait VerifyDigest: Default + Send + 'static {
+    const REQUIRED: bool = true;
+
+    fn update(&mut self, bytes: &[u8]);
+
+    fn verify(&mut self, parts: &[DigestPart]) -> bool;
+}
+
+#[async_trait::async_trait(?Send)]
+impl<C, D, K> actix_web_lab::extract::RequestSignatureScheme for SignatureScheme<C, D, K>
+where
+    C: ConfigGenerator,
+    D: VerifyDigest,
+    K: PrivateKey,
+{
+    type Signature = Signature<D, K>;
+
+    type Error = actix_web::Error;
+
+    async fn init(req: &actix_web::HttpRequest) -> Result<Self, Self::Error> {
+        let config = C::config();
+
+        let unverified = begin_verify(
+            &config,
+            req.method(),
+            req.uri().path_and_query(),
+            req.headers(),
+        )?;
+
+        Ok(SignatureScheme {
+            config_generator: std::marker::PhantomData,
+            key: std::marker::PhantomData,
+            digest_verifier: Some(D::default()),
+            unverified,
+        })
+    }
+
+    async fn consume_chunk(
+        &mut self,
+        _: &actix_web::HttpRequest,
+        chunk: actix_web::web::Bytes,
+    ) -> Result<(), Self::Error> {
+        if D::REQUIRED {
+            let mut verifier = self
+                .digest_verifier
+                .take()
+                .expect("consume_chunk polled concurrently");
+
+            self.digest_verifier = Some(
+                actix_web::web::block(move || {
+                    verifier.update(&chunk);
+                    verifier
+                })
+                .await
+                .expect("Panic in verifier update"),
+            );
+        }
+
+        Ok(())
+    }
+
+    async fn finalize(
+        mut self,
+        req: &actix_web::HttpRequest,
+    ) -> Result<Self::Signature, Self::Error> {
+        let key = K::init(req, self.unverified.key_id(), self.unverified.algorithm())
+            .await
+            .map_err(Into::into)?;
+
+        let digest_parts = if D::REQUIRED {
+            req.headers()
+                .get("digest")
+                .and_then(|digest| parse_digest(digest))
+        } else {
+            None
+        };
+
+        Ok(Signature {
+            key,
+            unverified: self.unverified,
+            digest_verifier: self
+                .digest_verifier
+                .take()
+                .expect("finalize called more than once"),
+            digest_parts,
+        })
+    }
+
+    fn verify(
+        signature: Self::Signature,
+        _: &actix_web::HttpRequest,
+    ) -> Result<Self::Signature, Self::Error> {
+        let Signature {
+            mut key,
+            unverified,
+            mut digest_verifier,
+            digest_parts,
+        } = signature;
+
+        if !unverified
+            .verify(|sig, signing_string| key.verify(sig, signing_string))
+            .map_err(Into::into)?
+        {
+            return Err(Error::Signature.into());
+        }
+
+        if D::REQUIRED {
+            if !digest_verifier.verify(digest_parts.as_deref().unwrap_or(&[])) {
+                return Err(Error::Digest.into());
+            }
+        }
+
+        let signature = Signature {
+            key,
+            unverified,
+            digest_verifier,
+            digest_parts,
+        };
+
+        Ok(signature)
+    }
+}
+
+fn parse_digest(h: &actix_web::http::header::HeaderValue) -> Option<Vec<DigestPart>> {
+    let h = h.to_str().ok()?.split(';').next()?;
+    let v: Vec<_> = h
+        .split(',')
+        .filter_map(|p| {
+            let mut iter = p.splitn(2, '=');
+            iter.next()
+                .and_then(|alg| iter.next().map(|value| (alg, value)))
+        })
+        .map(|(alg, value)| DigestPart {
+            algorithm: alg.to_owned(),
+            digest: value.to_owned(),
+        })
+        .collect();
+
+    if v.is_empty() {
+        None
+    } else {
+        Some(v)
+    }
+}
+
+fn begin_verify(
+    config: &Config,
+    method: &actix_web::http::Method,
+    path_and_query: Option<&actix_web::http::uri::PathAndQuery>,
+    headers: &actix_web::http::header::HeaderMap,
+) -> Result<http_signature_normalization::verify::Unverified, Error> {
+    let headers = headers
+        .iter()
+        .map(|(k, v)| v.to_str().map(|v| (k.to_string(), v.to_string())))
+        .collect::<Result<std::collections::BTreeMap<_, _>, actix_web::http::header::ToStrError>>(
+        )?;
+
+    let path_and_query = path_and_query
+        .map(|p| p.to_string())
+        .unwrap_or_else(|| "/".to_string());
+
+    let unverified = config.begin_verify(method.as_ref(), &path_and_query, headers)?;
+
+    Ok(unverified)
+}
+
+impl ConfigGenerator for () {
+    fn config() -> Config {
+        Config::new()
+    }
+}
+
+impl VerifyDigest for () {
+    const REQUIRED: bool = false;
+    fn update(&mut self, _: &[u8]) {}
+    fn verify(&mut self, _: &[DigestPart]) -> bool {
+        true
+    }
+}

http-signature-normalization-actix-extractor/src/sha2_digest.rs

@@ -0,0 +1,78 @@
+use crate::{DigestName, DigestPart, VerifyDigest};
+use sha2::{Sha224, Sha256, Sha384, Sha512};
+
+impl DigestName for Sha224 {
+    const NAME: &'static str = "SHA-244";
+}
+
+impl DigestName for Sha256 {
+    const NAME: &'static str = "SHA-256";
+}
+
+impl DigestName for Sha384 {
+    const NAME: &'static str = "SHA-384";
+}
+
+impl DigestName for Sha512 {
+    const NAME: &'static str = "SHA-512";
+}
+
+fn verify<D: sha2::Digest + sha2::digest::FixedOutputReset>(
+    digest: &mut D,
+    name: &str,
+    parts: &[DigestPart],
+) -> bool {
+    use subtle::ConstantTimeEq;
+
+    if let Some(decoded) = parts.iter().find_map(|p| {
+        if p.algorithm.to_lowercase() == name.to_lowercase() {
+            base64::decode(&p.digest).ok()
+        } else {
+            None
+        }
+    }) {
+        return digest.finalize_reset().ct_eq(&decoded).into();
+    }
+
+    false
+}
+
+impl VerifyDigest for Sha224 {
+    fn update(&mut self, part: &[u8]) {
+        sha2::Digest::update(self, part);
+    }
+
+    fn verify(&mut self, parts: &[DigestPart]) -> bool {
+        verify(self, Self::NAME, parts)
+    }
+}
+
+impl VerifyDigest for Sha256 {
+    fn update(&mut self, part: &[u8]) {
+        sha2::Digest::update(self, part);
+    }
+
+    fn verify(&mut self, parts: &[DigestPart]) -> bool {
+        verify(self, Self::NAME, parts)
+    }
+}
+
+impl VerifyDigest for Sha384 {
+    fn update(&mut self, part: &[u8]) {
+        sha2::Digest::update(self, part);
+    }
+
+    fn verify(&mut self, parts: &[DigestPart]) -> bool {
+        verify(self, Self::NAME, parts)
+    }
+}
+
+impl VerifyDigest for Sha512 {
+    fn update(&mut self, part: &[u8]) {
+        sha2::Digest::update(self, part);
+    }
+
+    fn verify(&mut self, parts: &[DigestPart]) -> bool {
+        verify(self, Self::NAME, parts)
+    }
+}