acme: add async-client feature

The client code is copied from propxmox-backup, without the load/safe
account functionality.

Signed-off-by: Dietmar Maurer <dietmar@proxmox.com>

proxmox-acme/Cargo.toml

@@ -22,6 +22,10 @@ openssl = { workspace = true, optional = true }
 native-tls = { workspace = true, optional = true }
 
 proxmox-schema = { workspace = true, optional = true, features = [ "api-macro" ] }
+proxmox-http = { workspace = true, optional = true, features = [ "client" ] }
+anyhow = { workspace = true, optional = true }
+bytes = { workspace = true, optional = true }
+hyper = { workspace = true, optional = true }
 
 [dependencies.ureq]
 optional = true
@@ -34,6 +38,7 @@ default = [ "impl" ]
 api-types = [ "dep:proxmox-schema" ]
 impl = [ "api-types", "dep:openssl" ]
 client = [ "impl", "dep:ureq", "dep:native-tls"]
+async-client = [ "impl", "dep:hyper", "dep:proxmox-http", "dep:anyhow", "dep:bytes" ]
 
 [dev-dependencies]
 anyhow.workspace = true

proxmox-acme/src/async_client.rs

@@ -0,0 +1,587 @@
+//! Async HTTP Client implementation for the ACME protocol.
+
+use anyhow::format_err;
+use bytes::Bytes;
+use hyper::{Body, Request};
+use serde::{Deserialize, Serialize};
+
+use proxmox_http::client::Client;
+
+use crate::account::AccountCreator;
+use crate::order::{Order, OrderData};
+use crate::Request as AcmeRequest;
+use crate::{Account, Authorization, Challenge, Directory, Error, ErrorResponse};
+
+/// A non-blocking Acme client using tokio/hyper.
+pub struct AcmeClient {
+    directory_url: String,
+    account: Option<Account>,
+    directory: Option<Directory>,
+    nonce: Option<String>,
+    http_client: Client,
+}
+
+impl AcmeClient {
+    /// Create a new ACME client for a given ACME directory URL.
+    pub fn new(directory_url: String) -> Self {
+        const USER_AGENT_STRING: &str = "proxmox-acme-client/1.0";
+        const TCP_KEEPALIVE_TIME: u32 = 120;
+
+        let options = proxmox_http::HttpOptions {
+            proxy_config: None, // fixme???
+            user_agent: Some(USER_AGENT_STRING.to_string()),
+            tcp_keepalive: Some(TCP_KEEPALIVE_TIME),
+        };
+
+        let http_client = Client::with_options(options);
+
+        Self {
+            directory_url,
+            account: None,
+            directory: None,
+            nonce: None,
+            http_client,
+        }
+    }
+
+    /// Get the current account, if there is one.
+    pub fn account(&self) -> Option<&Account> {
+        self.account.as_ref()
+    }
+
+    /// Set the account this client should use.
+    pub fn set_account(&mut self, account: Account) {
+        self.account = Some(account);
+    }
+
+    /// Convenience method to create a new account with a list of ACME compatible contact strings
+    /// (eg. `mailto:someone@example.com`).
+    ///
+    /// Please remember to persist the returned `Account` structure somewhere to not lose access to
+    /// the account!
+    ///
+    /// If an RSA key size is provided, an RSA key will be generated. Otherwise an EC key using the
+    /// P-256 curve will be generated.
+    pub async fn new_account<'a>(
+        &'a mut self,
+        tos_agreed: bool,
+        contact: Vec<String>,
+        rsa_bits: Option<u32>,
+        eab_creds: Option<(String, String)>,
+    ) -> Result<&'a Account, anyhow::Error> {
+        let mut account = Account::creator()
+            .set_contacts(contact)
+            .agree_to_tos(tos_agreed);
+
+        if let Some((eab_kid, eab_hmac_key)) = eab_creds {
+            account = account.set_eab_credentials(eab_kid, eab_hmac_key)?;
+        }
+
+        let account = if let Some(bits) = rsa_bits {
+            account.generate_rsa_key(bits)?
+        } else {
+            account.generate_ec_key()?
+        };
+
+        let _ = self.register_account(account).await?;
+
+        // unwrap: Setting `self.account` is literally this function's job, we just can't keep
+        // the borrow from from `self.register_account()` active due to clashes.
+        Ok(self.account.as_ref().unwrap())
+    }
+
+    /// Shortcut to `account().ok_or_else(...).key_authorization()`.
+    pub fn key_authorization(&self, token: &str) -> Result<String, anyhow::Error> {
+        Ok(Self::need_account(&self.account)?.key_authorization(token)?)
+    }
+
+    /// Shortcut to `account().ok_or_else(...).dns_01_txt_value()`.
+    /// the key authorization value.
+    pub fn dns_01_txt_value(&self, token: &str) -> Result<String, anyhow::Error> {
+        Ok(Self::need_account(&self.account)?.dns_01_txt_value(token)?)
+    }
+
+    async fn register_account(
+        &mut self,
+        account: AccountCreator,
+    ) -> Result<&Account, anyhow::Error> {
+        let mut retry = retry();
+        let mut response = loop {
+            retry.tick()?;
+
+            let (directory, nonce) = Self::get_dir_nonce(
+                &mut self.http_client,
+                &self.directory_url,
+                &mut self.directory,
+                &mut self.nonce,
+            )
+            .await?;
+            let request = account.request(directory, nonce)?;
+            match self.run_request(request).await {
+                Ok(response) => break response,
+                Err(err) if err.is_bad_nonce() => continue,
+                Err(err) => return Err(err.into()),
+            }
+        };
+
+        let account = account.response(response.location_required()?, &response.body)?;
+
+        self.account = Some(account);
+        Ok(self.account.as_ref().unwrap())
+    }
+
+    /// Update account data.
+    ///
+    /// Low-level version: we allow arbitrary data to be passed to the remote here, it's up to the
+    /// user to know what to do for now.
+    pub async fn update_account<T: Serialize>(
+        &mut self,
+        data: &T,
+    ) -> Result<&Account, anyhow::Error> {
+        let account = Self::need_account(&self.account)?;
+
+        let mut retry = retry();
+        let response = loop {
+            retry.tick()?;
+
+            let (_directory, nonce) = Self::get_dir_nonce(
+                &mut self.http_client,
+                &self.directory_url,
+                &mut self.directory,
+                &mut self.nonce,
+            )
+            .await?;
+
+            let request = account.post_request(&account.location, nonce, data)?;
+            match Self::execute(&mut self.http_client, request, &mut self.nonce).await {
+                Ok(response) => break response,
+                Err(err) if err.is_bad_nonce() => continue,
+                Err(err) => return Err(err.into()),
+            }
+        };
+
+        // unwrap: we've been keeping an immutable reference to it from the top of the method
+        let _ = account;
+        self.account.as_mut().unwrap().data = response.json()?;
+        // fixme: self.save()?;
+        Ok(self.account.as_ref().unwrap())
+    }
+
+    /// Method to create a new order for a set of domains.
+    ///
+    /// Please remember to persist the order somewhere (ideally along with the account data) in
+    /// order to finish & query it later on.
+    pub async fn new_order<I>(&mut self, domains: I) -> Result<Order, anyhow::Error>
+    where
+        I: IntoIterator<Item = String>,
+    {
+        let account = Self::need_account(&self.account)?;
+
+        let order = domains
+            .into_iter()
+            .fold(OrderData::new(), |order, domain| order.domain(domain));
+
+        let mut retry = retry();
+        loop {
+            retry.tick()?;
+
+            let (directory, nonce) = Self::get_dir_nonce(
+                &mut self.http_client,
+                &self.directory_url,
+                &mut self.directory,
+                &mut self.nonce,
+            )
+            .await?;
+
+            let mut new_order = account.new_order(&order, directory, nonce)?;
+            let mut response = match Self::execute(
+                &mut self.http_client,
+                new_order.request.take().unwrap(),
+                &mut self.nonce,
+            )
+            .await
+            {
+                Ok(response) => response,
+                Err(err) if err.is_bad_nonce() => continue,
+                Err(err) => return Err(err.into()),
+            };
+
+            return Ok(
+                new_order.response(response.location_required()?, response.bytes().as_ref())?
+            );
+        }
+    }
+
+    /// Low level "POST-as-GET" request.
+    async fn post_as_get(&mut self, url: &str) -> Result<AcmeResponse, anyhow::Error> {
+        let account = Self::need_account(&self.account)?;
+
+        let mut retry = retry();
+        loop {
+            retry.tick()?;
+
+            let (_directory, nonce) = Self::get_dir_nonce(
+                &mut self.http_client,
+                &self.directory_url,
+                &mut self.directory,
+                &mut self.nonce,
+            )
+            .await?;
+
+            let request = account.get_request(url, nonce)?;
+            match Self::execute(&mut self.http_client, request, &mut self.nonce).await {
+                Ok(response) => return Ok(response),
+                Err(err) if err.is_bad_nonce() => continue,
+                Err(err) => return Err(err.into()),
+            }
+        }
+    }
+
+    /// Low level POST request.
+    async fn post<T: Serialize>(
+        &mut self,
+        url: &str,
+        data: &T,
+    ) -> Result<AcmeResponse, anyhow::Error> {
+        let account = Self::need_account(&self.account)?;
+
+        let mut retry = retry();
+        loop {
+            retry.tick()?;
+
+            let (_directory, nonce) = Self::get_dir_nonce(
+                &mut self.http_client,
+                &self.directory_url,
+                &mut self.directory,
+                &mut self.nonce,
+            )
+            .await?;
+
+            let request = account.post_request(url, nonce, data)?;
+            match Self::execute(&mut self.http_client, request, &mut self.nonce).await {
+                Ok(response) => return Ok(response),
+                Err(err) if err.is_bad_nonce() => continue,
+                Err(err) => return Err(err.into()),
+            }
+        }
+    }
+
+    /// Request challenge validation. Afterwards, the challenge should be polled.
+    pub async fn request_challenge_validation(
+        &mut self,
+        url: &str,
+    ) -> Result<Challenge, anyhow::Error> {
+        Ok(self
+            .post(url, &serde_json::Value::Object(Default::default()))
+            .await?
+            .json()?)
+    }
+
+    /// Assuming the provided URL is an 'Authorization' URL, get and deserialize it.
+    pub async fn get_authorization(&mut self, url: &str) -> Result<Authorization, anyhow::Error> {
+        Ok(self.post_as_get(url).await?.json()?)
+    }
+
+    /// Assuming the provided URL is an 'Order' URL, get and deserialize it.
+    pub async fn get_order(&mut self, url: &str) -> Result<OrderData, anyhow::Error> {
+        Ok(self.post_as_get(url).await?.json()?)
+    }
+
+    /// Finalize an Order via its `finalize` URL property and the DER encoded CSR.
+    pub async fn finalize(&mut self, url: &str, csr: &[u8]) -> Result<(), anyhow::Error> {
+        let csr = base64::encode_config(csr, base64::URL_SAFE_NO_PAD);
+        let data = serde_json::json!({ "csr": csr });
+        self.post(url, &data).await?;
+        Ok(())
+    }
+
+    /// Download a certificate via its 'certificate' URL property.
+    ///
+    /// The certificate will be a PEM certificate chain.
+    pub async fn get_certificate(&mut self, url: &str) -> Result<Bytes, anyhow::Error> {
+        Ok(self.post_as_get(url).await?.body)
+    }
+
+    /// Revoke an existing certificate (PEM or DER formatted).
+    pub async fn revoke_certificate(
+        &mut self,
+        certificate: &[u8],
+        reason: Option<u32>,
+    ) -> Result<(), anyhow::Error> {
+        // TODO: This can also work without an account.
+        let account = Self::need_account(&self.account)?;
+
+        let revocation = account.revoke_certificate(certificate, reason)?;
+
+        let mut retry = retry();
+        loop {
+            retry.tick()?;
+
+            let (directory, nonce) = Self::get_dir_nonce(
+                &mut self.http_client,
+                &self.directory_url,
+                &mut self.directory,
+                &mut self.nonce,
+            )
+            .await?;
+
+            let request = revocation.request(directory, nonce)?;
+            match Self::execute(&mut self.http_client, request, &mut self.nonce).await {
+                Ok(_response) => return Ok(()),
+                Err(err) if err.is_bad_nonce() => continue,
+                Err(err) => return Err(err.into()),
+            }
+        }
+    }
+
+    fn need_account(account: &Option<Account>) -> Result<&Account, anyhow::Error> {
+        account
+            .as_ref()
+            .ok_or_else(|| format_err!("cannot use client without an account"))
+    }
+
+    /// Get the directory URL without querying the `Directory` structure.
+    ///
+    /// The difference to [`directory`](Client::directory()) is that this does not
+    /// attempt to fetch the directory data from the ACME server.
+    pub fn directory_url(&self) -> &str {
+        &self.directory_url
+    }
+}
+
+struct AcmeResponse {
+    body: Bytes,
+    location: Option<String>,
+    got_nonce: bool,
+}
+
+impl AcmeResponse {
+    /// Convenience helper to assert that a location header was part of the response.
+    fn location_required(&mut self) -> Result<String, anyhow::Error> {
+        self.location
+            .take()
+            .ok_or_else(|| format_err!("missing Location header"))
+    }
+
+    /// Convenience shortcut to perform json deserialization of the returned body.
+    fn json<T: for<'a> Deserialize<'a>>(&self) -> Result<T, Error> {
+        Ok(serde_json::from_slice(&self.body)?)
+    }
+
+    /// Convenience shortcut to get the body as bytes.
+    fn bytes(&self) -> &[u8] {
+        &self.body
+    }
+}
+
+impl AcmeClient {
+    /// Non-self-borrowing run_request version for borrow workarounds.
+    async fn execute(
+        http_client: &mut Client,
+        request: AcmeRequest,
+        nonce: &mut Option<String>,
+    ) -> Result<AcmeResponse, Error> {
+        let req_builder = Request::builder().method(request.method).uri(&request.url);
+
+        let http_request = if !request.content_type.is_empty() {
+            req_builder
+                .header("Content-Type", request.content_type)
+                .header("Content-Length", request.body.len())
+                .body(request.body.into())
+        } else {
+            req_builder.body(Body::empty())
+        }
+        .map_err(|err| Error::Custom(format!("failed to create http request: {}", err)))?;
+
+        let response = http_client
+            .request(http_request)
+            .await
+            .map_err(|err| Error::Custom(err.to_string()))?;
+        let (parts, body) = response.into_parts();
+
+        let status = parts.status.as_u16();
+        let body = hyper::body::to_bytes(body)
+            .await
+            .map_err(|err| Error::Custom(format!("failed to retrieve response body: {}", err)))?;
+
+        let got_nonce = if let Some(new_nonce) = parts.headers.get(crate::REPLAY_NONCE) {
+            let new_nonce = new_nonce.to_str().map_err(|err| {
+                Error::Client(format!(
+                    "received invalid replay-nonce header from ACME server: {}",
+                    err
+                ))
+            })?;
+            *nonce = Some(new_nonce.to_owned());
+            true
+        } else {
+            false
+        };
+
+        if parts.status.is_success() {
+            if status != request.expected {
+                return Err(Error::InvalidApi(format!(
+                    "ACME server responded with unexpected status code: {:?}",
+                    parts.status
+                )));
+            }
+
+            let location = parts
+                .headers
+                .get("Location")
+                .map(|header| {
+                    header.to_str().map(str::to_owned).map_err(|err| {
+                        Error::Client(format!(
+                            "received invalid location header from ACME server: {}",
+                            err
+                        ))
+                    })
+                })
+                .transpose()?;
+
+            return Ok(AcmeResponse {
+                body,
+                location,
+                got_nonce,
+            });
+        }
+
+        let error: ErrorResponse = serde_json::from_slice(&body).map_err(|err| {
+            Error::Client(format!(
+                "error status with improper error ACME response: {}",
+                err
+            ))
+        })?;
+
+        if error.ty == crate::error::BAD_NONCE {
+            if !got_nonce {
+                return Err(Error::InvalidApi(
+                    "badNonce without a new Replay-Nonce header".to_string(),
+                ));
+            }
+            return Err(Error::BadNonce);
+        }
+
+        Err(Error::Api(error))
+    }
+
+    /// Low-level API to run an n API request. This automatically updates the current nonce!
+    async fn run_request(&mut self, request: AcmeRequest) -> Result<AcmeResponse, Error> {
+        Self::execute(&mut self.http_client, request, &mut self.nonce).await
+    }
+
+    /// Get the Directory information.
+    pub async fn directory(&mut self) -> Result<&Directory, Error> {
+        Ok(Self::get_directory(
+            &mut self.http_client,
+            &self.directory_url,
+            &mut self.directory,
+            &mut self.nonce,
+        )
+        .await?
+        .0)
+    }
+
+    async fn get_directory<'a, 'b>(
+        http_client: &mut Client,
+        directory_url: &str,
+        directory: &'a mut Option<Directory>,
+        nonce: &'b mut Option<String>,
+    ) -> Result<(&'a Directory, Option<&'b str>), Error> {
+        if let Some(d) = directory {
+            return Ok((d, nonce.as_deref()));
+        }
+
+        let response = Self::execute(
+            http_client,
+            AcmeRequest {
+                url: directory_url.to_string(),
+                method: "GET",
+                content_type: "",
+                body: String::new(),
+                expected: 200,
+            },
+            nonce,
+        )
+        .await?;
+
+        *directory = Some(Directory::from_parts(
+            directory_url.to_string(),
+            response.json()?,
+        ));
+
+        Ok((directory.as_ref().unwrap(), nonce.as_deref()))
+    }
+
+    /// Like `get_directory`, but if the directory provides no nonce, also performs a `HEAD`
+    /// request on the new nonce URL.
+    async fn get_dir_nonce<'a, 'b>(
+        http_client: &mut Client,
+        directory_url: &str,
+        directory: &'a mut Option<Directory>,
+        nonce: &'b mut Option<String>,
+    ) -> Result<(&'a Directory, &'b str), Error> {
+        // this let construct is a lifetime workaround:
+        let _ = Self::get_directory(http_client, directory_url, directory, nonce).await?;
+        let dir = directory.as_ref().unwrap(); // the above fails if it couldn't fill this option
+        if nonce.is_none() {
+            // this is also a lifetime issue...
+            let _ = Self::get_nonce(http_client, nonce, dir.new_nonce_url()).await?;
+        };
+        Ok((dir, nonce.as_deref().unwrap()))
+    }
+
+    /// Convenience method to get the ToS URL from the contained `Directory`.
+    ///
+    /// This requires mutable self as the directory information may be lazily loaded, which can
+    /// fail.
+    pub async fn terms_of_service_url(&mut self) -> Result<Option<&str>, Error> {
+        Ok(self.directory().await?.terms_of_service_url())
+    }
+
+    async fn get_nonce<'a>(
+        http_client: &mut Client,
+        nonce: &'a mut Option<String>,
+        new_nonce_url: &str,
+    ) -> Result<&'a str, Error> {
+        let response = Self::execute(
+            http_client,
+            AcmeRequest {
+                url: new_nonce_url.to_owned(),
+                method: "HEAD",
+                content_type: "",
+                body: String::new(),
+                expected: 200,
+            },
+            nonce,
+        )
+        .await?;
+
+        if !response.got_nonce {
+            return Err(Error::InvalidApi(
+                "no new nonce received from new nonce URL".to_string(),
+            ));
+        }
+
+        nonce
+            .as_deref()
+            .ok_or_else(|| Error::Client("failed to update nonce".to_string()))
+    }
+}
+
+/// bad nonce retry count helper
+struct Retry(usize);
+
+const fn retry() -> Retry {
+    Retry(0)
+}
+
+impl Retry {
+    fn tick(&mut self) -> Result<(), Error> {
+        if self.0 >= 3 {
+            Err(Error::Client("kept getting a badNonce error!".to_string()))
+        } else {
+            self.0 += 1;
+            Ok(())
+        }
+    }
+}

proxmox-acme/src/lib.rs

@@ -89,3 +89,6 @@ pub const LOCATION: &str = "Location";
 pub mod client;
 #[cfg(feature = "client")]
 pub use client::Client;
+
+#[cfg(feature = "async-client")]
+pub mod async_client;