Implement otpauth URI parsing

3 files changed, 179 insertions, 6 deletions

diff --git a/Cargo.lock b/Cargo.lock
index 277ad6e..008d2ff 100644
--- a/Cargo.lock
+++ b/Cargo.lock
@@ -23,11 +23,26 @@ version = "0.3.3"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 
 [[package]]
+name = "idna"
+version = "0.1.5"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+dependencies = [
+ "matches 0.1.8 (registry+https://github.com/rust-lang/crates.io-index)",
+ "unicode-bidi 0.3.4 (registry+https://github.com/rust-lang/crates.io-index)",
+ "unicode-normalization 0.1.7 (registry+https://github.com/rust-lang/crates.io-index)",
+]
+
+[[package]]
 name = "libc"
 version = "0.2.46"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 
 [[package]]
+name = "matches"
+version = "0.1.8"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+
+[[package]]
 name = "mktemp"
 version = "0.3.1"
 source = "registry+https://github.com/rust-lang/crates.io-index"
@@ -41,9 +56,16 @@ version = "0.1.0"
 dependencies = [
  "argparse 0.2.2 (registry+https://github.com/rust-lang/crates.io-index)",
  "mktemp 0.3.1 (registry+https://github.com/rust-lang/crates.io-index)",
+ "percent-encoding 1.0.1 (registry+https://github.com/rust-lang/crates.io-index)",
+ "url 1.7.2 (registry+https://github.com/rust-lang/crates.io-index)",
 ]
 
 [[package]]
+name = "percent-encoding"
+version = "1.0.1"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+
+[[package]]
 name = "rand"
 version = "0.3.22"
 source = "registry+https://github.com/rust-lang/crates.io-index"
@@ -69,6 +91,29 @@ version = "0.3.24"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 
 [[package]]
+name = "unicode-bidi"
+version = "0.3.4"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+dependencies = [
+ "matches 0.1.8 (registry+https://github.com/rust-lang/crates.io-index)",
+]
+
+[[package]]
+name = "unicode-normalization"
+version = "0.1.7"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+
+[[package]]
+name = "url"
+version = "1.7.2"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+dependencies = [
+ "idna 0.1.5 (registry+https://github.com/rust-lang/crates.io-index)",
+ "matches 0.1.8 (registry+https://github.com/rust-lang/crates.io-index)",
+ "percent-encoding 1.0.1 (registry+https://github.com/rust-lang/crates.io-index)",
+]
+
+[[package]]
 name = "uuid"
 version = "0.1.18"
 source = "registry+https://github.com/rust-lang/crates.io-index"
@@ -101,11 +146,17 @@ source = "registry+https://github.com/rust-lang/crates.io-index"
 "checksum bitflags 1.0.4 (registry+https://github.com/rust-lang/crates.io-index)" = "228047a76f468627ca71776ecdebd732a3423081fcf5125585bcd7c49886ce12"
 "checksum fuchsia-zircon 0.3.3 (registry+https://github.com/rust-lang/crates.io-index)" = "2e9763c69ebaae630ba35f74888db465e49e259ba1bc0eda7d06f4a067615d82"
 "checksum fuchsia-zircon-sys 0.3.3 (registry+https://github.com/rust-lang/crates.io-index)" = "3dcaa9ae7725d12cdb85b3ad99a434db70b468c09ded17e012d86b5c1010f7a7"
+"checksum idna 0.1.5 (registry+https://github.com/rust-lang/crates.io-index)" = "38f09e0f0b1fb55fdee1f17470ad800da77af5186a1a76c026b679358b7e844e"
 "checksum libc 0.2.46 (registry+https://github.com/rust-lang/crates.io-index)" = "023a4cd09b2ff695f9734c1934145a315594b7986398496841c7031a5a1bbdbd"
+"checksum matches 0.1.8 (registry+https://github.com/rust-lang/crates.io-index)" = "7ffc5c5338469d4d3ea17d269fa8ea3512ad247247c30bd2df69e68309ed0a08"
 "checksum mktemp 0.3.1 (registry+https://github.com/rust-lang/crates.io-index)" = "77001ceb9eed65439f3dc2a2543f9ba1417d912686bf224a7738d0966e6dcd69"
+"checksum percent-encoding 1.0.1 (registry+https://github.com/rust-lang/crates.io-index)" = "31010dd2e1ac33d5b46a5b413495239882813e0369f8ed8a5e266f173602f831"
 "checksum rand 0.3.22 (registry+https://github.com/rust-lang/crates.io-index)" = "15a732abf9d20f0ad8eeb6f909bf6868722d9a06e1e50802b6a70351f40b4eb1"
 "checksum rand 0.4.3 (registry+https://github.com/rust-lang/crates.io-index)" = "8356f47b32624fef5b3301c1be97e5944ecdd595409cc5da11d05f211db6cfbd"
 "checksum rustc-serialize 0.3.24 (registry+https://github.com/rust-lang/crates.io-index)" = "dcf128d1287d2ea9d80910b5f1120d0b8eede3fbf1abe91c40d39ea7d51e6fda"
+"checksum unicode-bidi 0.3.4 (registry+https://github.com/rust-lang/crates.io-index)" = "49f2bd0c6468a8230e1db229cff8029217cf623c767ea5d60bfbd42729ea54d5"
+"checksum unicode-normalization 0.1.7 (registry+https://github.com/rust-lang/crates.io-index)" = "6a0180bc61fc5a987082bfa111f4cc95c4caff7f9799f3e46df09163a937aa25"
+"checksum url 1.7.2 (registry+https://github.com/rust-lang/crates.io-index)" = "dd4e7c0d531266369519a4aa4f399d748bd37043b00bde1e4ff1f60a120b355a"
 "checksum uuid 0.1.18 (registry+https://github.com/rust-lang/crates.io-index)" = "78c590b5bd79ed10aad8fb75f078a59d8db445af6c743e55c4a53227fc01c13f"
 "checksum winapi 0.3.6 (registry+https://github.com/rust-lang/crates.io-index)" = "92c1eb33641e276cfa214a0522acad57be5c56b10cb348b3c5117db75f3ac4b0"
 "checksum winapi-i686-pc-windows-gnu 0.4.0 (registry+https://github.com/rust-lang/crates.io-index)" = "ac3b87c63620426dd9b991e5ce0329eff545bccbbb34f3be09ff6fb6ab51b7b6"
diff --git a/Cargo.toml b/Cargo.toml
index 8315b8f..86135cc 100644
--- a/Cargo.toml
+++ b/Cargo.toml
@@ -12,3 +12,5 @@ license = "MIT"
 [dependencies]
 argparse = "0.2"
 mktemp = "0.3"
+percent-encoding = "1.0"
+url = "1.7"
diff --git a/src/main.rs b/src/main.rs
index 9c2a8c1..9fa1a72 100644
--- a/src/main.rs
+++ b/src/main.rs
@@ -2,18 +2,20 @@
 
 //! Reads OTP configuration from a QR code and writes it to an OTP slot on a Nitrokey device.
 
+use std::borrow;
 use std::fmt;
 use std::fs;
 use std::io;
 use std::path;
 use std::process;
-use std::string;
+use std::str;
 
 #[derive(Debug)]
 enum Error {
     IoError(io::Error),
     Error(String),
-    Utf8Error(string::FromUtf8Error),
+    UrlParseError(url::ParseError),
+    Utf8Error(str::Utf8Error),
 }
 
 impl fmt::Display for Error {
@@ -21,6 +23,7 @@ impl fmt::Display for Error {
         match *self {
             Error::IoError(ref err) => write!(f, "IO error: {}", err),
             Error::Error(ref string) => write!(f, "Error: {}", string),
+            Error::UrlParseError(ref err) => write!(f, "URL parse error: {}", err),
             Error::Utf8Error(ref err) => write!(f, "UTF-8 error: {}", err),
         }
     }
@@ -49,12 +52,29 @@ impl From<(&str, process::ExitStatus)> for Error {
     }
 }
 
-impl From<string::FromUtf8Error> for Error {
-    fn from(error: string::FromUtf8Error) -> Error {
+impl From<url::ParseError> for Error {
+    fn from(error: url::ParseError) -> Error {
+        Error::UrlParseError(error)
+    }
+}
+
+impl From<str::Utf8Error> for Error {
+    fn from(error: str::Utf8Error) -> Error {
         Error::Utf8Error(error)
     }
 }
 
+#[derive(Debug, PartialEq)]
+struct UrlData {
+    otp_type: String,
+    label: String,
+    secret: String,
+    issuer: Option<String>,
+    digits: Option<String>,
+    counter: Option<String>,
+    period: Option<String>,
+}
+
 #[derive(Debug)]
 struct Options {
     slot: u8,
@@ -113,7 +133,7 @@ fn decode_qr_code(path: &path::Path) -> Result<String, Error> {
         .arg(path)
         .output()?;
     if output.status.success() {
-        let output = String::from_utf8(output.stdout)?;
+        let output = String::from_utf8(output.stdout).map_err(|err| err.utf8_error())?;
         let urls = output
             .split("\n")
             .filter(|url| url.starts_with("otpauth://"))
@@ -131,12 +151,74 @@ fn decode_qr_code(path: &path::Path) -> Result<String, Error> {
     }
 }
 
+fn strip_issuer_prefix(label: String, issuer: &str) -> String {
+    let prefix = format!("{}:", issuer);
+    if label.starts_with(&prefix) {
+        let label = label.trim_left_matches(&prefix);
+        let label = label.trim_left_matches(" ");
+        label.to_string()
+    } else {
+        label
+    }
+}
+
+fn parse_url(url: &str) -> Result<UrlData, Error> {
+    let url = url::Url::parse(url)?;
+    let scheme = url.scheme();
+    if scheme != "otpauth" {
+        return Err(Error::Error(format!("Unexpected URL scheme: {}", scheme)));
+    }
+    let otp_type = match url.host_str() {
+        Some(host) => host.to_string(),
+        None => return Err(Error::from("otpauth URL does not contain type")),
+    };
+    let label = url.path();
+    let label = percent_encoding::percent_decode(label.as_bytes()).decode_utf8()?;
+    let label = label.trim_start_matches("/").to_string();
+    let mut secret: Option<String> = None;
+    let mut issuer: Option<String> = None;
+    let mut digits: Option<String> = None;
+    let mut counter: Option<String> = None;
+    let mut period: Option<String> = None;
+    for (key, value) in url.query_pairs() {
+        let field = match key {
+            borrow::Cow::Borrowed("secret") => Some(&mut secret),
+            borrow::Cow::Borrowed("issuer") => Some(&mut issuer),
+            borrow::Cow::Borrowed("digits") => Some(&mut digits),
+            borrow::Cow::Borrowed("counter") => Some(&mut counter),
+            borrow::Cow::Borrowed("period") => Some(&mut period),
+            _ => None,
+        };
+        if let Some(field) = field {
+            *field = Some(value.into_owned());
+        }
+    }
+    let label = match issuer {
+        Some(ref issuer) => strip_issuer_prefix(label, issuer),
+        None => label,
+    };
+    match secret {
+        Some(secret) => Ok(UrlData {
+            otp_type,
+            label,
+            secret,
+            issuer,
+            digits,
+            counter,
+            period,
+        }),
+        None => Err(Error::from("otpauth URL did not contain a secret")),
+    }
+}
+
 fn run(options: Options) -> Result<(), Error> {
     let path = match options.file {
         Some(ref file) => path::PathBuf::from(file),
         None => import_qr_code()?,
     };
-    println!("{}", decode_qr_code(&path)?);
+    let url = decode_qr_code(&path)?;
+    let url_data = parse_url(&url)?;
+    println!("{:?}", url_data);
     if options.file.is_none() {
         fs::remove_file(&path)?;
     }
@@ -156,3 +238,41 @@ fn main() {
     };
     process::exit(status);
 }
+
+#[cfg(test)]
+mod tests {
+    #[test]
+    fn parse_url() -> Result<(), super::Error> {
+        let result = super::parse_url(
+            "otpauth://totp/Example:alice@google.com?secret=JBSWY3DPEHPK3PXP&issuer=Example",
+        )?;
+        let expected = super::UrlData {
+            otp_type: "totp".to_string(),
+            label: "alice@google.com".to_string(),
+            secret: "JBSWY3DPEHPK3PXP".to_string(),
+            issuer: Some("Example".to_string()),
+            digits: None,
+            counter: None,
+            period: None,
+        };
+        assert_eq!(result, expected);
+
+        let result = super::parse_url("otpauth://totp/ACME%20Co:john.doe@email.com?secret=HXDMVJECJJWSRB3HWIZR4IFUGFTMXBOZ&issuer=ACME%20Co&algorithm=SHA1&digits=6&period=30")?;
+        let expected = super::UrlData {
+            otp_type: "totp".to_string(),
+            label: "john.doe@email.com".to_string(),
+            secret: "HXDMVJECJJWSRB3HWIZR4IFUGFTMXBOZ".to_string(),
+            issuer: Some("ACME Co".to_string()),
+            digits: Some("6".to_string()),
+            counter: None,
+            period: Some("30".to_string()),
+        };
+        assert_eq!(result, expected);
+
+        assert!(super::parse_url("otpauth://totp/test?secret=blubb").is_ok());
+        assert!(super::parse_url("otauth://totp/test?secret=blubb").is_err());
+        assert!(super::parse_url("otpauth://totp/test").is_err());
+
+        Ok(())
+    }
+}