move encryption stuff into new module

src/accountmanager.rs

@@ -1,9 +1,6 @@
-use aes::Aes256;
-use block_modes::block_padding::{NoPadding, Padding, Pkcs7};
-use block_modes::{BlockMode, Cbc};
+pub use crate::encryption::EntryEncryptionParams;
+use crate::encryption::EntryEncryptor;
 use log::*;
-use ring::pbkdf2;
-use ring::rand::SecureRandom;
 use serde::{Deserialize, Serialize};
 use std::fs::File;
 use std::io::{BufReader, Read, Write};
@@ -12,12 +9,11 @@ use std::sync::{Arc, Mutex};
 use steamguard::SteamGuardAccount;
 use thiserror::Error;
 
-type Aes256Cbc = Cbc<Aes256, NoPadding>;
-
 #[derive(Debug, Serialize, Deserialize)]
 pub struct Manifest {
-	pub encrypted: bool,
 	pub entries: Vec<ManifestEntry>,
+	/// Not really used, kept mostly for compatibility with SDA.
+	pub encrypted: bool,
 	/// Not implemented, kept for compatibility with SDA.
 	pub first_run: bool,
 	/// Not implemented, kept for compatibility with SDA.
@@ -48,14 +44,6 @@ pub struct ManifestEntry {
 	pub encryption: Option<EntryEncryptionParams>,
 }
 
-#[derive(Debug, Clone, Serialize, Deserialize)]
-pub struct EntryEncryptionParams {
-	#[serde(rename = "encryption_iv")]
-	pub iv: String,
-	#[serde(rename = "encryption_salt")]
-	pub salt: String,
-}
-
 impl Default for Manifest {
 	fn default() -> Self {
 		Manifest {
@@ -104,27 +92,12 @@ impl Manifest {
 			let account: SteamGuardAccount;
 			match (passkey, entry.encryption.as_ref()) {
 				(Some(passkey), Some(params)) => {
-					let key = get_encryption_key(&passkey.into(), &params.salt)?;
-					let iv = base64::decode(&params.iv)?;
-					let cipher = Aes256Cbc::new_from_slices(&key, &iv)?;
-
-					// This sucks.
 					let mut ciphertext: Vec<u8> = vec![];
 					reader.read_to_end(&mut ciphertext)?;
-					ciphertext = base64::decode(ciphertext)?;
-					let size: usize =
-						ciphertext.len() / 16 + (if ciphertext.len() % 16 == 0 { 0 } else { 1 });
-					let mut buffer = vec![0xffu8; 16 * size];
-					buffer[..ciphertext.len()].copy_from_slice(&ciphertext);
-					let mut decrypted = cipher.decrypt(&mut buffer)?;
-					if decrypted[0] != '{' as u8 {
-						return Err(ManifestAccountLoadError::DecryptionFailed);
-					}
-					// UnpadError does not implement Error for some fucking reason, so we have to do this.
-					let unpadded = Pkcs7::unpad(&mut decrypted)
-						.map_err(|_| ManifestAccountLoadError::DecryptionFailed)?;
-
-					let s = std::str::from_utf8(&unpadded).unwrap();
+					let plaintext = crate::encryption::LegacySdaCompatible::decrypt(
+						passkey, params, ciphertext,
+					)?;
+					let s = std::str::from_utf8(&plaintext).unwrap();
 					account = serde_json::from_str(&s)?;
 				}
 				(None, Some(_)) => {
@@ -191,32 +164,9 @@ impl Manifest {
 			let final_buffer: Vec<u8>;
 			match (passkey, entry.encryption.as_ref()) {
 				(Some(passkey), Some(params)) => {
-					let key = get_encryption_key(&passkey.into(), &params.salt)?;
-					let iv = base64::decode(&params.iv)?;
-					let cipher = Aes256Cbc::new_from_slices(&key, &iv)?;
-
-					// This also sucks. Extremely confusing.
-					let plaintext = serialized;
-					let origsize = plaintext.len();
-					let buffersize: usize =
-						(origsize / 16 + (if origsize % 16 == 0 { 0 } else { 1 })) * 16;
-					let mut buffer = vec![];
-					for chunk in plaintext.as_slice().chunks(256) {
-						let chunksize = chunk.len();
-						let buffersize =
-							(chunksize / 16 + (if chunksize % 16 == 0 { 0 } else { 1 })) * 16;
-						let mut chunkbuffer = vec![0xffu8; buffersize];
-						chunkbuffer[..chunksize].copy_from_slice(&chunk);
-						if buffersize != chunksize {
-							chunkbuffer = Pkcs7::pad(&mut chunkbuffer, chunksize, buffersize)
-								.unwrap()
-								.to_vec();
-						}
-						buffer.append(&mut chunkbuffer);
-					}
-					let ciphertext = cipher.encrypt(&mut buffer, buffersize)?;
-
-					final_buffer = base64::encode(&ciphertext).as_bytes().to_vec();
+					final_buffer = crate::encryption::LegacySdaCompatible::encrypt(
+						passkey, params, serialized,
+					)?;
 				}
 				(None, Some(_)) => {
 					bail!("maFiles are encrypted, but no passkey was provided.");
@@ -241,53 +191,18 @@ impl Manifest {
 	}
 }
 
-const PBKDF2_ITERATIONS: u32 = 50000; // This is excessive, but necessary to maintain compatibility with SteamDesktopAuthenticator.
-const SALT_LENGTH: usize = 8;
-const KEY_SIZE_BYTES: usize = 32;
-const IV_LENGTH: usize = 16;
-
-fn get_encryption_key(passkey: &String, salt: &String) -> anyhow::Result<[u8; KEY_SIZE_BYTES]> {
-	let password_bytes = passkey.as_bytes();
-	let salt_bytes = base64::decode(salt)?;
-	let mut full_key: [u8; KEY_SIZE_BYTES] = [0u8; KEY_SIZE_BYTES];
-	pbkdf2::derive(
-		pbkdf2::PBKDF2_HMAC_SHA1,
-		std::num::NonZeroU32::new(PBKDF2_ITERATIONS).unwrap(),
-		&salt_bytes,
-		password_bytes,
-		&mut full_key,
-	);
-	return Ok(full_key);
-}
-
-impl EntryEncryptionParams {
-	pub fn generate() -> EntryEncryptionParams {
-		let rng = ring::rand::SystemRandom::new();
-		let mut salt = [0u8; SALT_LENGTH];
-		let mut iv = [0u8; IV_LENGTH];
-		rng.fill(&mut salt).expect("Unable to generate salt.");
-		rng.fill(&mut iv).expect("Unable to generate IV.");
-		EntryEncryptionParams {
-			salt: base64::encode(salt),
-			iv: base64::encode(iv),
-		}
-	}
-}
-
 #[derive(Debug, Error)]
 pub enum ManifestAccountLoadError {
 	#[error("Manifest accounts are encrypted, but no passkey was provided.")]
 	MissingPasskey,
-	#[error("Failed to decrypt account.")]
-	#[from(block_modes::block_padding::UnpadError)]
-	DecryptionFailed,
+	#[error("Failed to decrypt account. {self:?}")]
+	DecryptionFailed(#[from] crate::encryption::EntryEncryptionError),
 	#[error("Failed to deserialize the account.")]
 	DeserializationFailed(#[from] serde_json::Error),
 	#[error(transparent)]
 	Unknown(#[from] anyhow::Error),
 }
 
-/// For some reason, these errors do not get converted to `ManifestAccountLoadError`s, even though they get converted into `anyhow::Error` just fine. I am too lazy to figure out why right now.
 impl From<block_modes::BlockModeError> for ManifestAccountLoadError {
 	fn from(error: block_modes::BlockModeError) -> Self {
 		return Self::Unknown(anyhow::Error::from(error));
@@ -525,26 +440,3 @@ mod tests {
 		);
 	}
 }
-
-#[cfg(test)]
-mod encryption_tests {
-	use super::*;
-
-	/// This test ensures compatibility with SteamDesktopAuthenticator and with previous versions of steamguard-cli
-	#[test]
-	fn test_encryption_key() {
-		assert_eq!(
-			get_encryption_key(&"password".into(), &"GMhL0N2hqXg=".into()).unwrap(),
-			base64::decode("KtiRa4/OxW83MlB6URf+Z8rAGj7CBY+pDlwD/NuVo6Y=")
-				.unwrap()
-				.as_slice()
-		);
-
-		assert_eq!(
-			get_encryption_key(&"password".into(), &"wTzTE9A6aN8=".into()).unwrap(),
-			base64::decode("Dqpej/3DqEat0roJaHmu3luYgDzRCUmzX94n4fqvWj8=")
-				.unwrap()
-				.as_slice()
-		);
-	}
-}

src/encryption.rs

@@ -0,0 +1,197 @@
+use aes::Aes256;
+use block_modes::block_padding::{NoPadding, Padding, Pkcs7};
+use block_modes::{BlockMode, Cbc};
+use ring::pbkdf2;
+use ring::rand::SecureRandom;
+use serde::{Deserialize, Serialize};
+use thiserror::Error;
+
+const PBKDF2_ITERATIONS: u32 = 50000; // This is excessive, but necessary to maintain compatibility with SteamDesktopAuthenticator.
+const SALT_LENGTH: usize = 8;
+const KEY_SIZE_BYTES: usize = 32;
+const IV_LENGTH: usize = 16;
+
+fn get_encryption_key(passkey: &String, salt: &String) -> anyhow::Result<[u8; KEY_SIZE_BYTES]> {
+	let password_bytes = passkey.as_bytes();
+	let salt_bytes = base64::decode(salt)?;
+	let mut full_key: [u8; KEY_SIZE_BYTES] = [0u8; KEY_SIZE_BYTES];
+	pbkdf2::derive(
+		pbkdf2::PBKDF2_HMAC_SHA1,
+		std::num::NonZeroU32::new(PBKDF2_ITERATIONS).unwrap(),
+		&salt_bytes,
+		password_bytes,
+		&mut full_key,
+	);
+	return Ok(full_key);
+}
+
+#[derive(Debug, Clone, Serialize, Deserialize)]
+pub struct EntryEncryptionParams {
+	#[serde(rename = "encryption_iv")]
+	pub iv: String,
+	#[serde(rename = "encryption_salt")]
+	pub salt: String,
+	#[serde(default, rename = "encryption_scheme")]
+	pub scheme: EncryptionScheme,
+}
+
+impl EntryEncryptionParams {
+	pub fn generate() -> EntryEncryptionParams {
+		let rng = ring::rand::SystemRandom::new();
+		let mut salt = [0u8; SALT_LENGTH];
+		let mut iv = [0u8; IV_LENGTH];
+		rng.fill(&mut salt).expect("Unable to generate salt.");
+		rng.fill(&mut iv).expect("Unable to generate IV.");
+		EntryEncryptionParams {
+			salt: base64::encode(salt),
+			iv: base64::encode(iv),
+			scheme: Default::default(),
+		}
+	}
+}
+
+#[derive(Debug, Clone, Serialize, Deserialize)]
+pub enum EncryptionScheme {
+	/// Encryption scheme that is compatible with SteamDesktopAuthenticator.
+	LegacySdaCompatible = 0,
+}
+
+impl Default for EncryptionScheme {
+	fn default() -> Self {
+		Self::LegacySdaCompatible
+	}
+}
+
+pub trait EntryEncryptor {
+	fn encrypt(
+		passkey: &String,
+		params: &EntryEncryptionParams,
+		plaintext: Vec<u8>,
+	) -> anyhow::Result<Vec<u8>, EntryEncryptionError>;
+	fn decrypt(
+		passkey: &String,
+		params: &EntryEncryptionParams,
+		ciphertext: Vec<u8>,
+	) -> anyhow::Result<Vec<u8>, EntryEncryptionError>;
+}
+
+/// Encryption scheme that is compatible with SteamDesktopAuthenticator.
+pub struct LegacySdaCompatible;
+
+type Aes256Cbc = Cbc<Aes256, NoPadding>;
+impl EntryEncryptor for LegacySdaCompatible {
+	// ngl, this logic sucks ass. its kinda annoying that the logic is not completely symetric.
+
+	fn encrypt(
+		passkey: &String,
+		params: &EntryEncryptionParams,
+		plaintext: Vec<u8>,
+	) -> anyhow::Result<Vec<u8>, EntryEncryptionError> {
+		let key = get_encryption_key(&passkey.into(), &params.salt)?;
+		let iv = base64::decode(&params.iv)?;
+		let cipher = Aes256Cbc::new_from_slices(&key, &iv)?;
+
+		let origsize = plaintext.len();
+		let buffersize: usize = (origsize / 16 + (if origsize % 16 == 0 { 0 } else { 1 })) * 16;
+		let mut buffer = vec![];
+		for chunk in plaintext.as_slice().chunks(256) {
+			let chunksize = chunk.len();
+			let buffersize = (chunksize / 16 + (if chunksize % 16 == 0 { 0 } else { 1 })) * 16;
+			let mut chunkbuffer = vec![0xffu8; buffersize];
+			chunkbuffer[..chunksize].copy_from_slice(&chunk);
+			if buffersize != chunksize {
+				chunkbuffer = Pkcs7::pad(&mut chunkbuffer, chunksize, buffersize)
+					.unwrap()
+					.to_vec();
+			}
+			buffer.append(&mut chunkbuffer);
+		}
+		let ciphertext = cipher.encrypt(&mut buffer, buffersize)?;
+		let final_buffer = base64::encode(&ciphertext);
+		return Ok(final_buffer.as_bytes().to_vec());
+	}
+
+	fn decrypt(
+		passkey: &String,
+		params: &EntryEncryptionParams,
+		ciphertext: Vec<u8>,
+	) -> anyhow::Result<Vec<u8>, EntryEncryptionError> {
+		let key = get_encryption_key(&passkey.into(), &params.salt)?;
+		let iv = base64::decode(&params.iv)?;
+		let cipher = Aes256Cbc::new_from_slices(&key, &iv)?;
+
+		let decoded = base64::decode(ciphertext)?;
+		let size: usize = decoded.len() / 16 + (if decoded.len() % 16 == 0 { 0 } else { 1 });
+		let mut buffer = vec![0xffu8; 16 * size];
+		buffer[..decoded.len()].copy_from_slice(&decoded);
+		let mut decrypted = cipher.decrypt(&mut buffer)?;
+		if decrypted[0] != '{' as u8 && decrypted[decrypted.len() - 1] != '}' as u8 {
+			return Err(EntryEncryptionError::IncorrectPasskey);
+		}
+		let unpadded = Pkcs7::unpad(&mut decrypted)?;
+		return Ok(unpadded.to_vec());
+	}
+}
+
+#[derive(Debug, Error)]
+pub enum EntryEncryptionError {
+	#[error("Incorrect passkey provided.")]
+	IncorrectPasskey,
+	#[error(transparent)]
+	Unknown(#[from] anyhow::Error),
+}
+
+/// For some reason, these errors do not get converted to `ManifestAccountLoadError`s, even though they get converted into `anyhow::Error` just fine. I am too lazy to figure out why right now.
+impl From<block_modes::BlockModeError> for EntryEncryptionError {
+	fn from(error: block_modes::BlockModeError) -> Self {
+		return Self::Unknown(anyhow::Error::from(error));
+	}
+}
+impl From<block_modes::InvalidKeyIvLength> for EntryEncryptionError {
+	fn from(error: block_modes::InvalidKeyIvLength) -> Self {
+		return Self::Unknown(anyhow::Error::from(error));
+	}
+}
+impl From<block_modes::block_padding::PadError> for EntryEncryptionError {
+	fn from(error: block_modes::block_padding::PadError) -> Self {
+		return Self::Unknown(anyhow!("PadError"));
+	}
+}
+impl From<block_modes::block_padding::UnpadError> for EntryEncryptionError {
+	fn from(error: block_modes::block_padding::UnpadError) -> Self {
+		return Self::Unknown(anyhow!("UnpadError"));
+	}
+}
+impl From<base64::DecodeError> for EntryEncryptionError {
+	fn from(error: base64::DecodeError) -> Self {
+		return Self::Unknown(anyhow::Error::from(error));
+	}
+}
+impl From<std::io::Error> for EntryEncryptionError {
+	fn from(error: std::io::Error) -> Self {
+		return Self::Unknown(anyhow::Error::from(error));
+	}
+}
+
+#[cfg(test)]
+mod tests {
+	use super::*;
+
+	/// This test ensures compatibility with SteamDesktopAuthenticator and with previous versions of steamguard-cli
+	#[test]
+	fn test_encryption_key() {
+		assert_eq!(
+			get_encryption_key(&"password".into(), &"GMhL0N2hqXg=".into()).unwrap(),
+			base64::decode("KtiRa4/OxW83MlB6URf+Z8rAGj7CBY+pDlwD/NuVo6Y=")
+				.unwrap()
+				.as_slice()
+		);
+
+		assert_eq!(
+			get_encryption_key(&"password".into(), &"wTzTE9A6aN8=".into()).unwrap(),
+			base64::decode("Dqpej/3DqEat0roJaHmu3luYgDzRCUmzX94n4fqvWj8=")
+				.unwrap()
+				.as_slice()
+		);
+	}
+}

src/main.rs

@@ -21,6 +21,7 @@ extern crate dirs;
 extern crate ring;
 mod accountmanager;
 mod demos;
+mod encryption;
 mod tui;
 
 fn cli() -> App<'static, 'static> {
@@ -190,7 +191,9 @@ fn main() {
 			Ok(_) => break,
 			Err(
 				accountmanager::ManifestAccountLoadError::MissingPasskey
-				| accountmanager::ManifestAccountLoadError::DecryptionFailed,
+				| accountmanager::ManifestAccountLoadError::DecryptionFailed(
+					encryption::EntryEncryptionError::IncorrectPasskey,
+				),
 			) => {
 				if passkey.is_some() {
 					error!("Incorrect passkey");