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Diffstat (limited to 'src/passwords.rs')
-rw-r--r-- | src/passwords.rs | 102 |
1 files changed, 102 insertions, 0 deletions
diff --git a/src/passwords.rs b/src/passwords.rs new file mode 100644 index 0000000..efc3f96 --- /dev/null +++ b/src/passwords.rs @@ -0,0 +1,102 @@ +//! Passwords for encryption. + +use pbkdf2::{ + password_hash::{PasswordHasher, SaltString}, + Pbkdf2, +}; +use rand::rngs::OsRng; +use serde::{Deserialize, Serialize}; +use std::io::prelude::Write; +use std::os::unix::fs::PermissionsExt; +use std::path::{Path, PathBuf}; + +const KEY_LEN: usize = 32; // Only size accepted by aead crate? + +/// Encryption password. +#[derive(Debug, Serialize, Deserialize, Clone)] +pub struct Passwords { + encryption: String, +} + +impl Passwords { + /// Create a new encryption password from a user-supplied passphrase. + pub fn new(passphrase: &str) -> Self { + let mut key = derive_password(passphrase); + let _ = key.split_off(KEY_LEN); + assert_eq!(key.len(), KEY_LEN); + Self { encryption: key } + } + + /// Get encryption key. + pub fn encryption_key(&self) -> &[u8] { + self.encryption.as_bytes() + } + + /// Load passwords from file. + pub fn load(filename: &Path) -> Result<Self, PasswordError> { + let data = std::fs::read(filename) + .map_err(|err| PasswordError::Read(filename.to_path_buf(), err))?; + serde_yaml::from_slice(&data) + .map_err(|err| PasswordError::Parse(filename.to_path_buf(), err)) + } + + /// Save passwords to file. + pub fn save(&self, filename: &Path) -> Result<(), PasswordError> { + let data = serde_yaml::to_string(&self).map_err(PasswordError::Serialize)?; + + let mut file = std::fs::File::create(filename) + .map_err(|err| PasswordError::Write(filename.to_path_buf(), err))?; + let metadata = file + .metadata() + .map_err(|err| PasswordError::Write(filename.to_path_buf(), err))?; + let mut permissions = metadata.permissions(); + + // Make readadable by owner only. We still have the open file + // handle, so we can write the content. + permissions.set_mode(0o400); + std::fs::set_permissions(filename, permissions) + .map_err(|err| PasswordError::Write(filename.to_path_buf(), err))?; + + // Write actual content. + file.write_all(data.as_bytes()) + .map_err(|err| PasswordError::Write(filename.to_path_buf(), err))?; + + Ok(()) + } +} + +/// Return name of password file, relative to configuration file. +pub fn passwords_filename(config_filename: &Path) -> PathBuf { + let mut filename = config_filename.to_path_buf(); + filename.set_file_name("passwords.yaml"); + filename +} + +fn derive_password(passphrase: &str) -> String { + let salt = SaltString::generate(&mut OsRng); + + Pbkdf2 + .hash_password(passphrase.as_bytes(), salt.as_salt()) + .unwrap() + .to_string() +} + +/// Possible errors from passwords. +#[derive(Debug, thiserror::Error)] +pub enum PasswordError { + /// Failed to make YAML when saving passwords. + #[error("failed to serialize passwords for saving: {0}")] + Serialize(serde_yaml::Error), + + /// Failed to save to file. + #[error("failed to save passwords to {0}: {1}")] + Write(PathBuf, std::io::Error), + + /// Failed read passwords file. + #[error("failed to read passwords from {0}: {1}")] + Read(PathBuf, std::io::Error), + + /// Failed to parse passwords file. + #[error("failed to parse saved passwords from {0}: {1}")] + Parse(PathBuf, serde_yaml::Error), +} |