job: add processing blacklist to global config

This brings support for webhook signature verification, making lohr
usable in a production setting.

.github/workflows/ci.yaml

@@ -0,0 +1,69 @@
+on: [push, pull_request]
+
+name: CI
+
+jobs:
+  check:
+    name: Check
+    runs-on: ubuntu-latest
+    steps:
+      - name: Checkout sources
+        uses: actions/checkout@v2
+
+      - name: Install nightly toolchain
+        uses: actions-rs/toolchain@v1
+        with:
+          profile: minimal
+          toolchain: nightly
+          override: true
+
+      - name: Run cargo check
+        uses: actions-rs/cargo@v1
+        with:
+          command: check
+
+  test:
+    name: Test Suite
+    runs-on: ubuntu-latest
+    steps:
+      - name: Checkout sources
+        uses: actions/checkout@v2
+
+      - name: Install nightly toolchain
+        uses: actions-rs/toolchain@v1
+        with:
+          profile: minimal
+          toolchain: nightly
+          override: true
+
+      - name: Run cargo test
+        uses: actions-rs/cargo@v1
+        with:
+          command: test
+
+  lints:
+    name: Lints
+    runs-on: ubuntu-latest
+    steps:
+      - name: Checkout sources
+        uses: actions/checkout@v2
+
+      - name: Install nightly toolchain
+        uses: actions-rs/toolchain@v1
+        with:
+          profile: minimal
+          toolchain: nightly
+          override: true
+          components: rustfmt, clippy
+
+      - name: Run cargo fmt
+        uses: actions-rs/cargo@v1
+        with:
+          command: fmt
+          args: --all -- --check
+
+      - name: Run cargo clippy
+        uses: actions-rs/clippy-check@v1
+        with:
+          token: ${{ secrets.GITHUB_TOKEN }}
+          args: --all-features -- -D warnings

Cargo.lock

@@ -336,6 +336,12 @@ dependencies = [
  "libc",
 ]
 
+[[package]]
+name = "hex"
+version = "0.4.3"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "7f24254aa9a54b5c858eaee2f5bccdb46aaf0e486a595ed5fd8f86ba55232a70"
+
 [[package]]
 name = "hkdf"
 version = "0.10.0"
@@ -491,14 +497,18 @@ dependencies = [
 
 [[package]]
 name = "lohr"
-version = "0.1.0"
+version = "0.3.0"
 dependencies = [
  "anyhow",
+ "hex",
+ "hmac",
  "log 0.4.14",
  "rocket",
  "rocket_contrib",
  "serde",
+ "serde_json",
  "serde_yaml",
+ "sha2",
 ]
 
 [[package]]

Cargo.toml

@@ -1,17 +1,23 @@
 [package]
 name = "lohr"
-version = "0.1.0"
+version = "0.3.0"
 authors = ["Antoine Martin <antoine@alarsyo.net>"]
 edition = "2018"
 license = "Apache-2.0 OR MIT"
 description = "A Git mirroring daemon"
+homepage = "https://github.com/alarsyo/lohr"
+repository = "https://github.com/alarsyo/lohr"
 
 # See more keys and their definitions at https://doc.rust-lang.org/cargo/reference/manifest.html
 
 [dependencies]
 anyhow = "1.0.40"
+hex = "0.4.3"
+hmac = "0.10.1"
 log = "0.4.14"
 rocket = "0.4.7"
 rocket_contrib = { version = "0.4.7", features = [ "json" ] }
 serde = { version = "1.0.125", features = [ "derive" ] }
+serde_json = "1.0.64"
 serde_yaml = "0.8.17"
+sha2 = "0.9.3"

LICENSE-APACHE

@@ -0,0 +1,201 @@
+                              Apache License
+                        Version 2.0, January 2004
+                     http://www.apache.org/licenses/
+
+TERMS AND CONDITIONS FOR USE, REPRODUCTION, AND DISTRIBUTION
+
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+
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+   any Contribution intentionally submitted for inclusion in the Work
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+   the terms of any separate license agreement you may have executed
+   with Licensor regarding such Contributions.
+
+6. Trademarks. This License does not grant permission to use the trade
+   names, trademarks, service marks, or product names of the Licensor,
+   except as required for reasonable and customary use in describing the
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+
+7. Disclaimer of Warranty. Unless required by applicable law or
+   agreed to in writing, Licensor provides the Work (and each
+   Contributor provides its Contributions) on an "AS IS" BASIS,
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+
+9. Accepting Warranty or Additional Liability. While redistributing
+   the Work or Derivative Works thereof, You may choose to offer,
+   and charge a fee for, acceptance of support, warranty, indemnity,
+   or other liability obligations and/or rights consistent with this
+   License. However, in accepting such obligations, You may act only
+   on Your own behalf and on Your sole responsibility, not on behalf
+   of any other Contributor, and only if You agree to indemnify,
+   defend, and hold each Contributor harmless for any liability
+   incurred by, or claims asserted against, such Contributor by reason
+   of your accepting any such warranty or additional liability.
+
+END OF TERMS AND CONDITIONS
+
+APPENDIX: How to apply the Apache License to your work.
+
+   To apply the Apache License to your work, attach the following
+   boilerplate notice, with the fields enclosed by brackets "[]"
+   replaced with your own identifying information. (Don't include
+   the brackets!)  The text should be enclosed in the appropriate
+   comment syntax for the file format. We also recommend that a
+   file or class name and description of purpose be included on the
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+
+Copyright 2021 Antoine Martin
+
+Licensed under the Apache License, Version 2.0 (the "License");
+you may not use this file except in compliance with the License.
+You may obtain a copy of the License at
+
+	http://www.apache.org/licenses/LICENSE-2.0
+
+Unless required by applicable law or agreed to in writing, software
+distributed under the License is distributed on an "AS IS" BASIS,
+WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+See the License for the specific language governing permissions and
+limitations under the License.

LICENSE-MIT

@@ -0,0 +1,19 @@
+The MIT License (MIT)
+Copyright (c) 2021 Antoine Martin
+
+Permission is hereby granted, free of charge, to any person obtaining a copy of
+this software and associated documentation files (the "Software"), to deal in
+the Software without restriction, including without limitation the rights to
+use, copy, modify, merge, publish, distribute, sublicense, and/or sell copies of
+the Software, and to permit persons to whom the Software is furnished to do so,
+subject to the following conditions:
+
+The above copyright notice and this permission notice shall be included in all
+copies or substantial portions of the Software.
+
+THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY, FITNESS
+FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR
+COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER
+IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN
+CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.

README.org

@@ -9,21 +9,108 @@ GitLab, for backup and visibility purposes.
 GitLab has a mirroring setting, but it doesn't allow for multiple mirrors, as
 far as I know. I also wanted my instance to be the single source of truth.
 
-* How it works
+** How it works
 
 Gitea is setup to send webhooks to my =lohr= server on every push update. When
 =lohr= receives a push, it clones the concerned repository, or updates it if
 already cloned. Then it pushes the update to *all remotes listed* in the [[file:.lohr][.lohr]]
 file at the repo root.
 
-** Destructive
+*** Destructive
 
 This is a very destructive process: anything removed from the single source of
 truth is effectively removed from any mirror as well.
 
-* Why lohr?
+** Setup
+
+*** Quickstart
+
+Setting up =lohr= should be quite simple:
+
+1. Create a =Rocket.toml= file and [[https://rocket.rs/v0.4/guide/configuration/][add your configuration]].
+
+2. Export a secret variable:
+
+   #+begin_src sh
+   $ export LOHR_SECRET=42 # please don't use this secret
+   #+end_src
+
+3. Run =lohr=:
+
+   #+begin_src sh
+   $ cargo run # or `cargo run --release` for production usage
+   #+end_src
+
+4. Configure your favorite git server to send a webhook to =lohr='s address on
+   every push event.
+
+   I used [[https://docs.gitea.io/en-us/webhooks/][Gitea's webhooks format]], but I *think* they're similar to GitHub and
+   GitLab's webhooks, so these should work too! (If they don't, *please* file an
+   issue!)
+
+   Don't forget to set the webhook secret to the one you chose above.
+
+5. Add a =.lohr= file containing the remotes you want to mirror this repo to:
+
+   #+begin_example
+   git@github.com:you/your_repo
+   #+end_example
+
+   and push it. That's it! =lohr= is mirroring your repo now.
+
+*** Configuration
+
+**** Home directory
+
+=lohr= needs a place to clone repos and store its data. By default, it's the
+current directory, but you can set the =LOHR_HOME= environment variable to
+customize it.
+
+**** Shared secret
+
+As shown in the quickstart guide, you *must* set the =LOHR_SECRET= environment
+variable.
+
+**** Extra remote configuration
+
+=lohr= looks for a =lohr-config.yaml= file in its =LOHR_HOME= directory. This
+file takes the following format:
+
+#+begin_src yaml
+default_remotes:
+  - "git@github:user"
+  - "git@gitlab:user"
+
+additional_remotes:
+  - "git@git.sr.ht:~user"
+#+end_src
+
+- ~default_remotes~ is a list of remotes to use if no ~.lohr~ file is found in a
+  repository.
+- ~additional_remotes~ is a list of remotes to add in any case, whether the
+  original set of remotes is set via ~default_remotes~ or via a =.lohr= file.
+
+Both settings take as input a list of "stems", i.e. incomplete remote addresses,
+to which the repo's name will be appended (so for example, if my
+~default_remotes~ contains ~git@github.com:alarsyo~, and a push event webhook
+is received for repository =git@gitlab.com:some/long/path/repo_name=, then the
+mirror destination will be =git@github.com:alarsyo/repo_name=.
+
+** Contributing
+
+I accept patches anywhere! Feel free to [[https://github.com/alarsyo/lohr/pulls][open a GitHub Pull Request]], [[https://gitlab.com/alarsyo/lohr/-/merge_requests][a GitLab
+Merge Request]], or [[https://lists.sr.ht/~alarsyo/lohr-dev][send me a patch by email]]!
+
+** Why lohr?
 
 I was looking for a cool name, and thought about the Magic Mirror in Snow White.
 Some *[[https://en.wikipedia.org/wiki/Magic_Mirror_(Snow_White)][furious wikipedia searching]]* later, I found that the Magic Mirror was
 probably inspired by [[http://spessartmuseum.de/seiten/schneewittchen_engl.html][the Talking Mirror in Lohr am Main]]. That's it, that's the
 story.
+
+** License
+
+=lohr= is distributed under the terms of both the MIT license and the Apache
+License (Version 2.0).
+
+See [[file:LICENSE-APACHE][LICENSE-APACHE]] and [[file:LICENSE-MIT][LICENSE-MIT]] for details.

src/job.rs

@@ -125,7 +125,13 @@ impl Job {
 
         let output = String::from_utf8(output.stdout)?;
 
-        Ok(Some(output.lines().map(String::from).collect()))
+        Ok(Some(
+            output
+                .lines()
+                .map(String::from)
+                .filter(|s| !s.is_empty())
+                .collect(),
+        ))
     }
 
     fn get_remotes(&self, config: &GlobalSettings) -> anyhow::Result<Vec<RepoUrl>> {
@@ -184,6 +190,13 @@ impl Job {
     }
 
     pub(crate) fn run(&mut self, homedir: &Path, config: &GlobalSettings) -> anyhow::Result<()> {
+        if config
+            .blacklist
+            .iter()
+            .any(|re| re.is_match(&self.repo.full_name))
+        {
+            return Ok(());
+        }
         let local_path = homedir.join(&self.repo.full_name);
         assert!(local_path.is_absolute());
         self.local_path = Some(local_path);

src/main.rs

@@ -10,7 +10,6 @@ use std::sync::{
 use std::thread;
 
 use rocket::{http::Status, post, routes, State};
-use rocket_contrib::json::Json;
 
 use log::error;
 
@@ -23,12 +22,14 @@ use job::Job;
 mod settings;
 use settings::GlobalSettings;
 
+mod signature;
+use signature::SignedJson;
+
 struct JobSender(Mutex<Sender<Job>>);
+struct Secret(String);
 
 #[post("/", data = "<payload>")]
-fn gitea_webhook(payload: Json<GiteaWebHook>, sender: State<JobSender>) -> Status {
+fn gitea_webhook(payload: SignedJson<GiteaWebHook>, sender: State<JobSender>) -> Status {
-    // TODO: validate Gitea signature
-
     {
         let sender = sender.0.lock().unwrap();
         let repo = &payload.repository;
@@ -66,6 +67,9 @@ fn main() -> anyhow::Result<()> {
     let homedir: PathBuf = homedir.into();
     let homedir = homedir.canonicalize().expect("LOHR_HOME isn't valid!");
 
+    let secret = env::var("LOHR_SECRET")
+        .expect("please provide a secret, otherwise anyone can send you a malicious webhook");
+
     let config = parse_config(homedir.clone())?;
 
     thread::spawn(move || {
@@ -75,6 +79,7 @@ fn main() -> anyhow::Result<()> {
     rocket::ignite()
         .mount("/", routes![gitea_webhook])
         .manage(JobSender(Mutex::new(sender)))
+        .manage(Secret(secret))
         .launch();
 
     Ok(())

src/settings.rs

@@ -10,4 +10,8 @@ pub(crate) struct GlobalSettings {
     /// List of remote stems to use for every repository
     #[serde(default)]
     pub additional_remotes: Vec<RepoUrl>,
+    /// List of regexes, if a repository's name matches any of the, it is not mirrored by `lohr`
+    /// even if it contains a `.lorh` file.
+    #[serde(with = "serde_regex")]
+    pub blacklist: Vec<regex::Regex>,
 }

src/signature.rs

@@ -0,0 +1,122 @@
+use std::{
+    io::Read,
+    ops::{Deref, DerefMut},
+};
+
+use rocket::{
+    data::{FromData, Outcome},
+    http::ContentType,
+    State,
+};
+use rocket::{
+    data::{Transform, Transformed},
+    http::Status,
+};
+use rocket::{Data, Request};
+
+use anyhow::anyhow;
+use serde::Deserialize;
+
+use crate::Secret;
+
+const X_GITEA_SIGNATURE: &str = "X-Gitea-Signature";
+
+fn validate_signature(secret: &str, signature: &str, data: &str) -> bool {
+    use hmac::{Hmac, Mac, NewMac};
+    use sha2::Sha256;
+
+    type HmacSha256 = Hmac<Sha256>;
+
+    let mut mac = HmacSha256::new_varkey(secret.as_bytes()).expect("this should never fail");
+
+    mac.update(data.as_bytes());
+
+    match hex::decode(signature) {
+        Ok(bytes) => mac.verify(&bytes).is_ok(),
+        Err(_) => false,
+    }
+}
+
+pub struct SignedJson<T>(pub T);
+
+impl<T> Deref for SignedJson<T> {
+    type Target = T;
+
+    fn deref(&self) -> &T {
+        &self.0
+    }
+}
+
+impl<T> DerefMut for SignedJson<T> {
+    fn deref_mut(&mut self) -> &mut T {
+        &mut self.0
+    }
+}
+
+const LIMIT: u64 = 1 << 20;
+
+// This is a one to one implementation of request_contrib::Json's FromData, but with HMAC
+// validation.
+//
+// Tracking issue for chaining Data guards to avoid this:
+// https://github.com/SergioBenitez/Rocket/issues/775
+impl<'a, T> FromData<'a> for SignedJson<T>
+where
+    T: Deserialize<'a>,
+{
+    type Error = anyhow::Error;
+    type Owned = String;
+    type Borrowed = str;
+
+    fn transform(
+        request: &Request,
+        data: Data,
+    ) -> rocket::data::Transform<Outcome<Self::Owned, Self::Error>> {
+        let size_limit = request.limits().get("json").unwrap_or(LIMIT);
+        let mut s = String::with_capacity(512);
+        match data.open().take(size_limit).read_to_string(&mut s) {
+            Ok(_) => Transform::Borrowed(Outcome::Success(s)),
+            Err(e) => Transform::Borrowed(Outcome::Failure((
+                Status::BadRequest,
+                anyhow!("couldn't read json: {}", e),
+            ))),
+        }
+    }
+
+    fn from_data(request: &Request, o: Transformed<'a, Self>) -> Outcome<Self, Self::Error> {
+        let json_ct = ContentType::new("application", "json");
+        if request.content_type() != Some(&json_ct) {
+            return Outcome::Failure((Status::BadRequest, anyhow!("wrong content type")));
+        }
+
+        let signatures = request.headers().get(X_GITEA_SIGNATURE).collect::<Vec<_>>();
+        if signatures.len() != 1 {
+            return Outcome::Failure((
+                Status::BadRequest,
+                anyhow!("request header needs exactly one signature"),
+            ));
+        }
+
+        let signature = signatures[0];
+
+        let content = o.borrowed()?;
+
+        let secret = request.guard::<State<Secret>>().unwrap();
+
+        if !validate_signature(&secret.0, &signature, content) {
+            return Outcome::Failure((Status::BadRequest, anyhow!("couldn't verify signature")));
+        }
+
+        let content = match serde_json::from_str(content) {
+            Ok(content) => content,
+            Err(e) => {
+                return Outcome::Failure((
+                    Status::BadRequest,
+                    anyhow!("couldn't parse json: {}", e),
+                ))
+            }
+        };
+
+        Outcome::Success(SignedJson(content))
+    }
+}