Add secret validation

Signed-off-by: trivernis <trivernis@protonmail.com>

Cargo.lock

@@ -70,6 +70,15 @@ version = "1.2.1"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 checksum = "cf1de2fe8c75bc145a2f577add951f8134889b4795d47466a54a5c846d691693"
 
+[[package]]
+name = "block-buffer"
+version = "0.9.0"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "4152116fd6e9dadb291ae18fc1ec3575ed6d84c29642d97890f4b4a3417297e4"
+dependencies = [
+ "generic-array",
+]
+
 [[package]]
 name = "bytes"
 version = "1.0.1"
@@ -128,6 +137,34 @@ dependencies = [
  "yaml-rust",
 ]
 
+[[package]]
+name = "cpufeatures"
+version = "0.1.5"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "66c99696f6c9dd7f35d486b9d04d7e6e202aa3e8c40d553f2fdf5e7e0c6a71ef"
+dependencies = [
+ "libc",
+]
+
+[[package]]
+name = "crypto-mac"
+version = "0.11.1"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "b1d1a86f49236c215f271d40892d5fc950490551400b02ef360692c29815c714"
+dependencies = [
+ "generic-array",
+ "subtle",
+]
+
+[[package]]
+name = "digest"
+version = "0.9.0"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "d3dd60d1080a57a05ab032377049e0591415d2b31afd7028356dbf3cc6dcb066"
+dependencies = [
+ "generic-array",
+]
+
 [[package]]
 name = "dirs"
 version = "3.0.2"
@@ -212,6 +249,16 @@ dependencies = [
  "pin-utils",
 ]
 
+[[package]]
+name = "generic-array"
+version = "0.14.4"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "501466ecc8a30d1d3b7fc9229b122b2ce8ed6e9d9223f1138d4babb253e51817"
+dependencies = [
+ "typenum",
+ "version_check",
+]
+
 [[package]]
 name = "getrandom"
 version = "0.2.3"
@@ -269,6 +316,22 @@ dependencies = [
  "libc",
 ]
 
+[[package]]
+name = "hex"
+version = "0.4.3"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "7f24254aa9a54b5c858eaee2f5bccdb46aaf0e486a595ed5fd8f86ba55232a70"
+
+[[package]]
+name = "hmac"
+version = "0.11.0"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "2a2a2320eb7ec0ebe8da8f744d7812d9fc4cb4d09344ac01898dbcb6a20ae69b"
+dependencies = [
+ "crypto-mac",
+ "digest",
+]
+
 [[package]]
 name = "http"
 version = "0.2.4"
@@ -436,7 +499,7 @@ dependencies = [
 
 [[package]]
 name = "multihook"
-version = "0.1.3"
+version = "0.1.4"
 dependencies = [
  "chrono",
  "colored",
@@ -444,6 +507,8 @@ dependencies = [
  "dirs",
  "fern",
  "glob",
+ "hex",
+ "hmac",
  "hyper",
  "jsonpath",
  "lazy_static",
@@ -451,6 +516,7 @@ dependencies = [
  "regex",
  "serde 1.0.127",
  "serde_json",
+ "sha2",
  "thiserror",
  "tokio",
  "toml",
@@ -529,6 +595,12 @@ version = "1.8.0"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 checksum = "692fcb63b64b1758029e0a96ee63e049ce8c5948587f2f7208df04625e5f6b56"
 
+[[package]]
+name = "opaque-debug"
+version = "0.3.0"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "624a8340c38c1b80fd549087862da4ba43e08858af025b236e509b6649fc13d5"
+
 [[package]]
 name = "pest"
 version = "1.0.6"
@@ -685,6 +757,19 @@ dependencies = [
  "serde 1.0.127",
 ]
 
+[[package]]
+name = "sha2"
+version = "0.9.5"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "b362ae5752fd2137731f9fa25fd4d9058af34666ca1966fb969119cc35719f12"
+dependencies = [
+ "block-buffer",
+ "cfg-if",
+ "cpufeatures",
+ "digest",
+ "opaque-debug",
+]
+
 [[package]]
 name = "signal-hook-registry"
 version = "1.4.0"
@@ -716,6 +801,12 @@ version = "1.1.0"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 checksum = "a2eb9349b6444b326872e140eb1cf5e7c522154d69e7a0ffb0fb81c06b37543f"
 
+[[package]]
+name = "subtle"
+version = "2.4.1"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "6bdef32e8150c2a081110b42772ffe7d7c9032b606bc226c8260fd97e0976601"
+
 [[package]]
 name = "syn"
 version = "0.11.11"
@@ -862,6 +953,12 @@ version = "0.2.3"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 checksum = "59547bce71d9c38b83d9c0e92b6066c4253371f15005def0c30d9657f50c7642"
 
+[[package]]
+name = "typenum"
+version = "1.13.0"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "879f6906492a7cd215bfa4cf595b600146ccfac0c79bcbd1f3000162af5e8b06"
+
 [[package]]
 name = "unicode-xid"
 version = "0.0.4"

Cargo.toml

@@ -4,7 +4,7 @@ description = "A webhook server"
 authors = ["trivernis <trivernis@protonmail.com>"]
 license = "GPL-3.0"
 readme = "README.md"
-version = "0.1.3"
+version = "0.1.4"
 edition = "2018"
 repository = "https://github.com/Trivernis/multihook.git"
 
@@ -24,6 +24,9 @@ fern = "0.6.0"
 serde_json = "1.0.66"
 jsonpath = "0.1.1"
 regex = "1.5.4"
+hmac = "0.11.0"
+sha2 = "0.9.5"
+hex = "0.4.3"
 
 [dependencies.serde]
 version = "1.0.127"

README.md

@@ -46,6 +46,9 @@ allow_parallel = true
 [endpoints.error]
 path = "error"
 action = "echo '{{$.books.*.title}}'"
+# Validate secrets according to different parsing rules
+# Currently only GitHub secrets are supported
+secret = { value = "my secret", type = "GitHub"}
 
 [endpoints.testscript]
 path = "script"

src/main.rs

@@ -5,6 +5,7 @@ use utils::settings::get_settings;
 
 use crate::server::HookServer;
 
+mod secret_validation;
 mod server;
 pub(crate) mod utils;
 

src/secret_validation/github.rs

@@ -0,0 +1,28 @@
+use crate::secret_validation::SecretValidator;
+use hmac::{Hmac, Mac, NewMac};
+use hyper::HeaderMap;
+use sha2::Sha256;
+
+pub struct GithubSecretValidator;
+
+static X_HUB_SIGNATURE_256_HEADER: &str = "X-Hub-Signature-256";
+
+impl SecretValidator for GithubSecretValidator {
+    fn validate(&self, headers: &HeaderMap, body: &[u8], secret: &[u8]) -> bool {
+        log::debug!("Validating GitHub Secret");
+        if let Some(github_sum) = headers.get(X_HUB_SIGNATURE_256_HEADER) {
+            let mut mac = Hmac::<Sha256>::new_from_slice(secret).unwrap();
+            mac.update(body);
+
+            let decoded_secret = if let Ok(decoded) = hex::decode(github_sum) {
+                decoded
+            } else {
+                return false;
+            };
+            mac.verify(&decoded_secret).is_ok()
+        } else {
+            log::debug!("Missing Signature Header");
+            false
+        }
+    }
+}

src/secret_validation/mod.rs

@@ -0,0 +1,22 @@
+mod github;
+
+use crate::secret_validation::github::GithubSecretValidator;
+use hyper::HeaderMap;
+use serde::{Deserialize, Serialize};
+
+#[derive(Serialize, Deserialize, Clone, Debug)]
+pub enum SecretFormat {
+    GitHub,
+}
+
+impl SecretFormat {
+    pub fn validator(&self) -> impl SecretValidator {
+        match self {
+            SecretFormat::GitHub => GithubSecretValidator,
+        }
+    }
+}
+
+pub trait SecretValidator {
+    fn validate(&self, headers: &HeaderMap, body: &[u8], secret: &[u8]) -> bool;
+}

src/server/action.rs

@@ -1,6 +1,8 @@
+use crate::secret_validation::SecretValidator;
 use crate::server::command_template::CommandTemplate;
-use crate::utils::error::MultihookResult;
+use crate::utils::error::{MultihookError, MultihookResult};
-use crate::utils::settings::EndpointSettings;
+use crate::utils::settings::{EndpointSettings, SecretSettings};
+use hyper::http::request::Parts;
 use hyper::{Body, Request};
 use serde_json::Value;
 use std::fs::read_to_string;
@@ -17,10 +19,16 @@ pub struct HookAction {
     command: CommandTemplate,
     parallel_lock: Arc<Semaphore>,
     run_detached: bool,
+    secret: Option<SecretSettings>,
 }
 
 impl HookAction {
-    pub fn new<S: ToString>(command: S, parallel: bool, detached: bool) -> Self {
+    pub fn new<S: ToString>(
+        command: S,
+        parallel: bool,
+        detached: bool,
+        secret: Option<SecretSettings>,
+    ) -> Self {
         let parallel_lock = if parallel {
             Semaphore::new(MAX_CONCURRENCY)
         } else {
@@ -30,12 +38,17 @@ impl HookAction {
             command: CommandTemplate::new(command),
             parallel_lock: Arc::new(parallel_lock),
             run_detached: detached,
+            secret,
         }
     }
 
     pub async fn execute(&self, req: Request<Body>) -> MultihookResult<()> {
-        let body = hyper::body::to_bytes(req.into_body()).await?.to_vec();
+        let (parts, body) = req.into_parts();
+        let body = hyper::body::to_bytes(body).await?.to_vec();
+
+        self.validate_secret(&parts, &body)?;
         let body = String::from_utf8(body)?;
+
         if self.run_detached {
             tokio::spawn({
                 let action = self.clone();
@@ -52,6 +65,16 @@ impl HookAction {
         }
     }
 
+    fn validate_secret(&self, parts: &Parts, body: &Vec<u8>) -> MultihookResult<()> {
+        if let Some(secret) = &self.secret {
+            let validator = secret.format.validator();
+            if !validator.validate(&parts.headers, &body, &secret.value.as_bytes()) {
+                return Err(MultihookError::InvalidSecret);
+            }
+        }
+        Ok(())
+    }
+
     async fn execute_command(&self, body: &str) -> MultihookResult<()> {
         let json_body: Value = serde_json::from_str(body).unwrap_or_default();
         let command = self.command.evaluate(&json_body);
@@ -85,6 +108,11 @@ impl From<&EndpointSettings> for HookAction {
         let action = endpoint.action.clone();
         let path = PathBuf::from(&action);
         let contents = read_to_string(path).unwrap_or(action);
-        Self::new(contents, endpoint.allow_parallel, endpoint.run_detached)
+        Self::new(
+            contents,
+            endpoint.allow_parallel,
+            endpoint.run_detached,
+            endpoint.secret.clone(),
+        )
     }
 }

src/server/mod.rs

@@ -1,10 +1,11 @@
 use std::sync::Arc;
 
+use hyper::{Body, Method, Response};
+
 use action::HookAction;
 
 use crate::server::http::{HTTPCallback, HTTPServer};
 use crate::utils::error::MultihookResult;
-use hyper::{Body, Method, Response};
 
 pub mod action;
 pub mod command_template;

src/utils/error.rs

@@ -22,4 +22,7 @@ pub enum MultihookError {
 
     #[error(transparent)]
     Hyper(#[from] hyper::Error),
+
+    #[error("Secret validation failed.")]
+    InvalidSecret,
 }

src/utils/settings.rs

@@ -1,3 +1,4 @@
+use crate::secret_validation::SecretFormat;
 use crate::utils::error::MultihookResult;
 use config::File;
 use lazy_static::lazy_static;
@@ -25,6 +26,13 @@ pub struct EndpointSettings {
     pub allow_parallel: bool,
     #[serde(default)]
     pub run_detached: bool,
+    pub secret: Option<SecretSettings>,
+}
+
+#[derive(Serialize, Deserialize, Clone, Debug)]
+pub struct SecretSettings {
+    pub value: String,
+    pub format: SecretFormat,
 }
 
 impl Default for Settings {