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//! slack_http_verifier verifies request signatures from Slacks HTTP Events API, //! as described //! [here](https://api.slack.com/docs/verifying-requests-from-slack#sdk_support). //! //! ## Usage //! //! If you're using the `http` crate, requests can be verified directly //! ```edition2018 //! # use slack_http_verifier::SlackHTTPVerifier; //! //! # // Samples from Slack's documentation page //! # let my_secret_key: &str = "8f742231b10e8888abcd99yyyzzz85a5"; //! # let slack_sample_timestamp: &str = "1531420618"; //! # let slack_sample_body: &str = //! # "token=xyzz0WbapA4vBCDEFasx0q6G&team_id=T1DC2JH3J&team_domain=testteamnow&channel_id=G8PSS9T3V&channel_name=foobar&user_id=U2CERLKJA&user_name=roadrunner&command=%2Fwebhook-collect&text=&response_url=https%3A%2F%2Fhooks.slack.com%2Fcommands%2FT1DC2JH3J%2F397700885554%2F96rGlfmibIGlgcZRskXaIFfN&trigger_id=398738663015.47445629121.803a0bc887a14d10d2c447fce8b6703c"; //! # let slack_sample_sig: &str = //! # "v0=a2114d57b48eac39b9ad189dd8316235a7b4a8d21a10bd27519666489c69b503"; //! //! let http_verifier = SlackHTTPVerifier::new(my_secret_key).unwrap(); //! //! // ... //! // Receive requests //! //! # let req = http::Request::builder() //! # .header("X-Slack-Request-Timestamp", slack_sample_timestamp) //! # .header("X-Slack-Signature", slack_sample_sig) //! # .body(slack_sample_body) //! # .unwrap(); //! //! http_verifier.verify(&req).unwrap(); //! ``` //! //! //! ```edition2018 //! # use slack_http_verifier::SlackVerifier; //! //! # // Samples from Slack's documentation page //! # let my_secret_key: &str = "8f742231b10e8888abcd99yyyzzz85a5"; //! //! let verifier = SlackVerifier::new(my_secret_key).unwrap(); //! //! // ... //! // Receive requests, extract from your framework //! //! # let slack_sample_timestamp: &str = "1531420618"; //! # let slack_sample_body: &str = //! # "token=xyzz0WbapA4vBCDEFasx0q6G&team_id=T1DC2JH3J&team_domain=testteamnow&channel_id=G8PSS9T3V&channel_name=foobar&user_id=U2CERLKJA&user_name=roadrunner&command=%2Fwebhook-collect&text=&response_url=https%3A%2F%2Fhooks.slack.com%2Fcommands%2FT1DC2JH3J%2F397700885554%2F96rGlfmibIGlgcZRskXaIFfN&trigger_id=398738663015.47445629121.803a0bc887a14d10d2c447fce8b6703c"; //! # let slack_sample_sig: &str = //! # "v0=a2114d57b48eac39b9ad189dd8316235a7b4a8d21a10bd27519666489c69b503"; //! //! verifier //! .verify(slack_sample_timestamp, slack_sample_body, slack_sample_sig) //! .unwrap(); //! ``` use crypto_mac::Mac; use hmac::Hmac; use sha2::Sha256; const SLACK_TIMESTAMP_HEADER: &str = "X-Slack-Request-Timestamp"; const SLACK_SIGNATURE_HEADER: &str = "X-Slack-Signature"; type Sha256Hmac = Hmac<Sha256>; mod error { use http::header::ToStrError; #[derive(Debug)] pub struct InvalidKeyLengthError; #[derive(Debug)] pub enum VerificationError { MissingTimestampHeader, MissingSignatureHeader, SignatureMismatch, UnencodableHeader(ToStrError), } } use error::*; /// Verifies Slack [http request][http::Request]s are signed by the given secret. /// A convenience wrapper around [`SlackVerifier`][SlackVerifier]. #[derive(Clone, Debug)] pub struct SlackHTTPVerifier { verifier: SlackVerifier, } impl SlackHTTPVerifier { /// Returns a new SlackHTTPVerifier. /// /// ```edition2018 /// # use slack_http_verifier::SlackHTTPVerifier; /// /// let verifier = SlackHTTPVerifier::new("8f742231b10e8888abcd99yyyzzz85a5").unwrap(); /// ``` pub fn new<S: AsRef<[u8]>>(secret: S) -> Result<Self, InvalidKeyLengthError> { let verifier = SlackVerifier::new(secret)?; Ok(SlackHTTPVerifier { verifier }) } /// Verifies the given request. /// /// ```edition2018 /// # use slack_http_verifier::SlackHTTPVerifier; /// # let verifier = SlackHTTPVerifier::new("8f742231b10e8888abcd99yyyzzz85a5").unwrap(); /// # let req = http::Request::builder() /// # .header("X-Slack-Request-Timestamp", "1531420618") /// # .header("X-Slack-Signature", "v0=a2114d57b48eac39b9ad189dd8316235a7b4a8d21a10bd27519666489c69b503") /// # .body("token=xyzz0WbapA4vBCDEFasx0q6G&team_id=T1DC2JH3J&team_domain=testteamnow&channel_id=G8PSS9T3V&channel_name=foobar&user_id=U2CERLKJA&user_name=roadrunner&command=%2Fwebhook-collect&text=&response_url=https%3A%2F%2Fhooks.slack.com%2Fcommands%2FT1DC2JH3J%2F397700885554%2F96rGlfmibIGlgcZRskXaIFfN&trigger_id=398738663015.47445629121.803a0bc887a14d10d2c447fce8b6703c") /// # .unwrap(); /// /// assert!(verifier.verify(&req).is_ok()) /// ``` pub fn verify<T>(&self, req: &http::Request<T>) -> Result<(), VerificationError> where T: AsRef<str>, { let ts = req .headers() .get(SLACK_TIMESTAMP_HEADER) .ok_or(VerificationError::MissingTimestampHeader)? .to_str() .map_err(VerificationError::UnencodableHeader)?; let exp_sig = req .headers() .get(SLACK_SIGNATURE_HEADER) .ok_or(VerificationError::MissingSignatureHeader)? .to_str() .map_err(VerificationError::UnencodableHeader)?; self.verifier.verify(ts, req.body().as_ref(), exp_sig) } } unsafe impl Send for SlackHTTPVerifier {} unsafe impl Sync for SlackHTTPVerifier {} /// Verifies raw request bodies are signed by Slack's secret. /// An alternative if it is inconvenient/impossible to use /// SlackHTTPVerifier #[derive(Clone, Debug)] pub struct SlackVerifier { mac: Sha256Hmac, } impl SlackVerifier { /// Returns a new SlackVerifier. /// /// ```edition2018 /// # use slack_http_verifier::SlackVerifier; /// let verifier = SlackVerifier::new("8f742231b10e8888abcd99yyyzzz85a5").unwrap(); /// ``` pub fn new<S: AsRef<[u8]>>(secret: S) -> Result<SlackVerifier, InvalidKeyLengthError> { match Sha256Hmac::new_varkey(secret.as_ref()) { Ok(mac) => Ok(SlackVerifier { mac }), Err(_) => Err(InvalidKeyLengthError), } } /// Verifies the given request. /// /// ```edition2018 /// # use slack_http_verifier::SlackVerifier; /// # let ts_header = "1531420618"; /// # let req_body = "token=xyzz0WbapA4vBCDEFasx0q6G&team_id=T1DC2JH3J&team_domain=testteamnow&channel_id=G8PSS9T3V&channel_name=foobar&user_id=U2CERLKJA&user_name=roadrunner&command=%2Fwebhook-collect&text=&response_url=https%3A%2F%2Fhooks.slack.com%2Fcommands%2FT1DC2JH3J%2F397700885554%2F96rGlfmibIGlgcZRskXaIFfN&trigger_id=398738663015.47445629121.803a0bc887a14d10d2c447fce8b6703c"; /// # let sig_header = "v0=a2114d57b48eac39b9ad189dd8316235a7b4a8d21a10bd27519666489c69b503"; /// # let verifier = SlackVerifier::new("8f742231b10e8888abcd99yyyzzz85a5").unwrap(); /// /// assert!(verifier.verify(ts_header, req_body, sig_header).is_ok()); /// ``` pub fn verify(&self, ts: &str, body: &str, exp_sig: &str) -> Result<(), VerificationError> { let basestring = format!("v0:{}:{}", ts, body); let mut mac = self.mac.clone(); mac.input(basestring.as_bytes()); let sig = format!("v0={}", hex::encode(mac.result().code().as_slice())); match sig == exp_sig { true => Ok(()), false => Err(VerificationError::SignatureMismatch), } } } unsafe impl Send for SlackVerifier {} unsafe impl Sync for SlackVerifier {} #[cfg(test)] mod tests { use super::*; const SLACK_SAMPLE_KEY: &str = "8f742231b10e8888abcd99yyyzzz85a5"; const SLACK_SAMPLE_TIMESTAMP: &str = "1531420618"; const SLACK_SAMPLE_BODY: &str = "token=xyzz0WbapA4vBCDEFasx0q6G&team_id=T1DC2JH3J&team_domain=testteamnow&channel_id=G8PSS9T3V&channel_name=foobar&user_id=U2CERLKJA&user_name=roadrunner&command=%2Fwebhook-collect&text=&response_url=https%3A%2F%2Fhooks.slack.com%2Fcommands%2FT1DC2JH3J%2F397700885554%2F96rGlfmibIGlgcZRskXaIFfN&trigger_id=398738663015.47445629121.803a0bc887a14d10d2c447fce8b6703c"; const SLACK_SAMPLE_SIG: &str = "v0=a2114d57b48eac39b9ad189dd8316235a7b4a8d21a10bd27519666489c69b503"; #[test] fn site_example() { let verifier = SlackVerifier::new(SLACK_SAMPLE_KEY).unwrap(); assert!(verifier .verify(SLACK_SAMPLE_TIMESTAMP, SLACK_SAMPLE_BODY, SLACK_SAMPLE_SIG) .is_ok()); } #[test] fn site_example_http_req() { let verifier = SlackHTTPVerifier::new(SLACK_SAMPLE_KEY).unwrap(); let req = http::Request::builder() .header(SLACK_TIMESTAMP_HEADER, SLACK_SAMPLE_TIMESTAMP) .header(SLACK_SIGNATURE_HEADER, SLACK_SAMPLE_SIG) .body(SLACK_SAMPLE_BODY) .unwrap(); assert!(verifier.verify(&req).is_ok()); } }