123 lines
3.2 KiB
Rust
123 lines
3.2 KiB
Rust
use std::{
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io::Read,
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ops::{Deref, DerefMut},
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};
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use rocket::{
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data::{FromData, Outcome},
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http::ContentType,
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State,
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};
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use rocket::{
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data::{Transform, Transformed},
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http::Status,
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};
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use rocket::{Data, Request};
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use anyhow::anyhow;
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use serde::Deserialize;
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use crate::Secret;
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const X_GITEA_SIGNATURE: &str = "X-Gitea-Signature";
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fn validate_signature(secret: &str, signature: &str, data: &str) -> bool {
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use hmac::{Hmac, Mac, NewMac};
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use sha2::Sha256;
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type HmacSha256 = Hmac<Sha256>;
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let mut mac = HmacSha256::new_varkey(secret.as_bytes()).expect("this should never fail");
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mac.update(data.as_bytes());
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match hex::decode(signature) {
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Ok(bytes) => mac.verify(&bytes).is_ok(),
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Err(_) => false,
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}
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}
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pub struct SignedJson<T>(pub T);
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impl<T> Deref for SignedJson<T> {
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type Target = T;
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fn deref(&self) -> &T {
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&self.0
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}
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}
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impl<T> DerefMut for SignedJson<T> {
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fn deref_mut(&mut self) -> &mut T {
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&mut self.0
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}
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}
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const LIMIT: u64 = 1 << 20;
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// This is a one to one implementation of request_contrib::Json's FromData, but with HMAC
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// validation.
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//
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// Tracking issue for chaining Data guards to avoid this:
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// https://github.com/SergioBenitez/Rocket/issues/775
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impl<'a, T> FromData<'a> for SignedJson<T>
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where
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T: Deserialize<'a>,
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{
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type Error = anyhow::Error;
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type Owned = String;
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type Borrowed = str;
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fn transform(
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request: &Request,
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data: Data,
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) -> rocket::data::Transform<Outcome<Self::Owned, Self::Error>> {
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let size_limit = request.limits().get("json").unwrap_or(LIMIT);
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let mut s = String::with_capacity(512);
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match data.open().take(size_limit).read_to_string(&mut s) {
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Ok(_) => Transform::Borrowed(Outcome::Success(s)),
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Err(e) => Transform::Borrowed(Outcome::Failure((
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Status::BadRequest,
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anyhow!("couldn't read json: {}", e),
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))),
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}
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}
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fn from_data(request: &Request, o: Transformed<'a, Self>) -> Outcome<Self, Self::Error> {
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let json_ct = ContentType::new("application", "json");
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if request.content_type() != Some(&json_ct) {
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return Outcome::Failure((Status::BadRequest, anyhow!("wrong content type")));
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}
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let signatures = request.headers().get(X_GITEA_SIGNATURE).collect::<Vec<_>>();
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if signatures.len() != 1 {
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return Outcome::Failure((
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Status::BadRequest,
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anyhow!("request header needs exactly one signature"),
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));
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}
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let signature = signatures[0];
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let content = o.borrowed()?;
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let secret = request.guard::<State<Secret>>().unwrap();
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if !validate_signature(&secret.0, &signature, content) {
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return Outcome::Failure((Status::BadRequest, anyhow!("couldn't verify signature")));
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}
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let content = match serde_json::from_str(content) {
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Ok(content) => content,
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Err(e) => {
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return Outcome::Failure((
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Status::BadRequest,
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anyhow!("couldn't parse json: {}", e),
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))
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}
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};
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Outcome::Success(SignedJson(content))
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}
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}
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