Merge pull request #200 from teloxide/hide_token_in_errors

Hide bot token in errors

CHANGELOG.md

@@ -11,6 +11,14 @@ and this project adheres to [Semantic Versioning](https://semver.org/spec/v2.0.0
 
 - `user.id` now uses `UserId` type, `ChatId` now represents only _chat id_, not channel username, all `chat_id` function parameters now accept `Recipient` [**BC**]
 
+## 0.4.5 - 2022-04-03
+
+### Fixed
+
+- Hide bot token in errors ([#200][200])
+
+[200]: https://github.com/teloxide/teloxide-core/pull/200
+
 ## 0.4.4 - 2022-04-21
 
 ### Added

Cargo.toml

@@ -1,7 +1,7 @@
 [package]
 name = "teloxide-core"
 description = "Core part of the `teloxide` library - telegram bot API client"
-version = "0.4.4"
+version = "0.4.5"
 edition = "2018"
 
 license = "MIT"

src/bot/download.rs

@@ -41,6 +41,7 @@ impl<'w> Download<'w> for Bot {
             &self.token,
             path,
         )
+        .map(|res| res.map_err(crate::errors::hide_token))
         .boxed()
     }
 }

src/errors.rs

@@ -1,19 +1,19 @@
 use std::io;
 
-use derive_more::From;
 use serde::Deserialize;
 use thiserror::Error;
 
 /// An error caused by downloading a file.
-#[derive(Debug, Error, From)]
+#[derive(Debug, Error)]
 pub enum DownloadError {
     /// A network error while downloading a file from Telegram.
     #[error("A network error: {0}")]
+    // NOTE: this variant must not be created by anything except the From impl
     Network(#[source] reqwest::Error),
 
     /// An I/O error while writing a file to destination.
     #[error("An I/O error: {0}")]
-    Io(#[source] std::io::Error),
+    Io(#[from] std::io::Error),
 }
 
 /// An error caused by sending a request to Telegram.
@@ -35,6 +35,7 @@ pub enum RequestError {
 
     /// Network error while sending a request to Telegram.
     #[error("A network error: {0}")]
+    // NOTE: this variant must not be created by anything except the From impl
     Network(#[source] reqwest::Error),
 
     /// Error while parsing a response from Telegram.
@@ -727,3 +728,65 @@ pub enum ApiError {
     #[error("Unknown error: {0:?}")]
     Unknown(String),
 }
+
+impl From<reqwest::Error> for DownloadError {
+    fn from(error: reqwest::Error) -> Self {
+        DownloadError::Network(hide_token(error))
+    }
+}
+
+impl From<reqwest::Error> for RequestError {
+    fn from(error: reqwest::Error) -> Self {
+        RequestError::Network(hide_token(error))
+    }
+}
+
+/// Replaces token in the url in the error with `token:redacted` string.
+pub(crate) fn hide_token(mut error: reqwest::Error) -> reqwest::Error {
+    let url = match error.url_mut() {
+        Some(url) => url,
+        None => return error,
+    };
+
+    if let Some(mut segments) = url.path_segments() {
+        // Usually the url looks like "bot<token>/..." or "file/bot<token>/...".
+        let (beginning, segment) = match segments.next() {
+            Some("file") => ("file/", segments.next()),
+            segment => ("", segment),
+        };
+
+        if let Some(token) = segment.and_then(|s| s.strip_prefix("bot")) {
+            // make sure that what we are about to delete looks like a bot token
+            if let Some((id, secret)) = token.split_once(':') {
+                // The part before the : in the token is the id of the bot.
+                let id_character = |c: char| c.is_ascii_digit();
+
+                // The part after the : in the token is the secret.
+                //
+                // In all bot tokens we could find the secret is 35 characters long and is
+                // 0-9a-zA-Z_- only.
+                //
+                // It would be nice to research if TBA always has 35 character secrets or if it
+                // is just a coincidence.
+                const SECRET_LENGTH: usize = 35;
+                let secret_character = |c: char| c.is_ascii_alphanumeric() || c == '-' || c == '_';
+
+                if secret.len() >= SECRET_LENGTH
+                    && id.chars().all(id_character)
+                    && secret.chars().all(secret_character)
+                {
+                    // found token, hide only the token
+                    let without_token =
+                        &url.path()[(beginning.len() + "/bot".len() + token.len())..];
+                    let redacted = format!("{beginning}token:redacted{without_token}");
+
+                    url.set_path(&redacted);
+                    return error;
+                }
+            }
+        }
+    }
+
+    // couldn't find token in the url, hide the whole url
+    error.without_url()
+}

src/net/request.rs

@@ -37,18 +37,14 @@ where
     let request = client
         .post(crate::net::method_url(api_url, token, method_name))
         .multipart(params)
-        .build()
-        .map_err(RequestError::Network)?;
+        .build()?;
 
     // FIXME: uncomment this, when reqwest starts setting default timeout early
     // if let Some(timeout) = timeout_hint {
     //     *request.timeout_mut().get_or_insert(Duration::ZERO) += timeout;
     // }
 
-    let response = client
-        .execute(request)
-        .await
-        .map_err(RequestError::Network)?;
+    let response = client.execute(request).await?;
 
     process_response(response).await
 }
@@ -81,18 +77,14 @@ where
         .post(crate::net::method_url(api_url, token, method_name))
         .header(CONTENT_TYPE, HeaderValue::from_static("application/json"))
         .body(params)
-        .build()
-        .map_err(RequestError::Network)?;
+        .build()?;
 
     // FIXME: uncomment this, when reqwest starts setting default timeout early
     // if let Some(timeout) = timeout_hint {
     //     *request.timeout_mut().get_or_insert(Duration::ZERO) += timeout;
     // }
 
-    let response = client
-        .execute(request)
-        .await
-        .map_err(RequestError::Network)?;
+    let response = client.execute(request).await?;
 
     process_response(response).await
 }
@@ -105,7 +97,7 @@ where
         tokio::time::sleep(DELAY_ON_SERVER_ERROR).await;
     }
 
-    let text = response.text().await.map_err(RequestError::Network)?;
+    let text = response.text().await?;
 
     serde_json::from_str::<TelegramResponse<T>>(&text)
         .map_err(|source| RequestError::InvalidJson {