ssh-cipher: enable and fix workspace-level lints (#517)

Applies the workspace-level config added in #509 to this crate and fixes
any failures.

Author: tarcieri

ssh-cipher/Cargo.toml

@@ -52,6 +52,8 @@ zeroize = [
     "poly1305?/zeroize"
 ]
 
+[lints]
+workspace = true
+
 [package.metadata.docs.rs]
 all-features = true
-rustdoc-args = ["--cfg", "docsrs"]

ssh-cipher/README.md

@@ -19,13 +19,6 @@ ciphers.
 Built on the pure Rust cryptography implementations maintained by the
 [RustCrypto] organization.
 
-## Minimum Supported Rust Version
-
-This crate requires **Rust 1.85** at a minimum.
-
-We may change the MSRV in the future, but it will be accompanied by a minor
-version bump.
-
 ## License
 
 Licensed under either of:

ssh-cipher/src/chacha20poly1305.rs

@@ -9,6 +9,7 @@ use aead::{
     inout::InOutBuf,
 };
 use cipher::{KeyIvInit, StreamCipher, StreamCipherSeek};
+use core::fmt::{self, Debug};
 use ctutils::CtEq;
 use poly1305::{Poly1305, universal_hash::UniversalHash};
 
@@ -59,14 +60,13 @@ impl AeadCore for ChaCha20Poly1305 {
 }
 
 impl AeadInOut for ChaCha20Poly1305 {
-    // Required methods
     fn encrypt_inout_detached(
         &self,
         nonce: &ChaChaNonce,
         associated_data: &[u8],
         buffer: InOutBuf<'_, '_, u8>,
     ) -> Result<Tag> {
-        Cipher::new(&self.key, nonce).encrypt(associated_data, buffer)
+        Cipher::new(&self.key, *nonce).encrypt(associated_data, buffer)
     }
 
     fn decrypt_inout_detached(
@@ -76,7 +76,13 @@ impl AeadInOut for ChaCha20Poly1305 {
         buffer: InOutBuf<'_, '_, u8>,
         tag: &Tag,
     ) -> Result<()> {
-        Cipher::new(&self.key, nonce).decrypt(associated_data, buffer, tag)
+        Cipher::new(&self.key, *nonce).decrypt(associated_data, buffer, tag)
+    }
+}
+
+impl Debug for ChaCha20Poly1305 {
+    fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
+        f.debug_struct("ChaCha20Poly1305").finish_non_exhaustive()
     }
 }
 
@@ -98,8 +104,8 @@ struct Cipher {
 
 impl Cipher {
     /// Create a new cipher instance.
-    pub fn new(key: &ChaChaKey, nonce: &ChaChaNonce) -> Self {
-        let mut cipher = ChaCha20::new(key, nonce);
+    fn new(key: &ChaChaKey, nonce: ChaChaNonce) -> Self {
+        let mut cipher = ChaCha20::new(key, &nonce);
         let mut poly1305_key = poly1305::Key::default();
         cipher.apply_keystream(&mut poly1305_key);
 
@@ -113,15 +119,15 @@ impl Cipher {
 
     /// Encrypt the provided `buffer` in-place, returning the Poly1305 authentication tag.
     #[inline]
-    pub fn encrypt(mut self, aad: &[u8], mut buffer: InOutBuf<'_, '_, u8>) -> Result<Tag> {
+    fn encrypt(mut self, aad: &[u8], mut buffer: InOutBuf<'_, '_, u8>) -> Result<Tag> {
         self.cipher.apply_keystream_inout(buffer.reborrow());
         compute_mac(self.mac, aad, buffer.get_out())
     }
 
     /// Decrypt the provided `buffer` in-place, verifying it against the provided Poly1305
     /// authentication `tag`.
     #[inline]
-    pub fn decrypt(mut self, aad: &[u8], buffer: InOutBuf<'_, '_, u8>, tag: &Tag) -> Result<()> {
+    fn decrypt(mut self, aad: &[u8], buffer: InOutBuf<'_, '_, u8>, tag: &Tag) -> Result<()> {
         let expected_tag = compute_mac(self.mac, aad, buffer.get_in())?;
 
         if expected_tag.ct_eq(tag).into() {

ssh-cipher/src/decryptor.rs

@@ -2,21 +2,19 @@
 
 use crate::{Cipher, Error, Result};
 use cipher::KeyIvInit;
+use core::fmt::{self, Debug};
 
 #[cfg(feature = "aes-ctr")]
 use crate::{Ctr128BE, encryptor::ctr_encrypt as ctr_decrypt};
-
-#[cfg(feature = "tdes")]
-use des::TdesEde3;
-
 #[cfg(any(feature = "aes-cbc", feature = "aes-ctr"))]
 use aes::{Aes128, Aes192, Aes256};
-
 #[cfg(any(feature = "aes-cbc", feature = "tdes"))]
 use cipher::{
     Block,
     block::{BlockCipherDecrypt, BlockModeDecrypt},
 };
+#[cfg(feature = "tdes")]
+use des::TdesEde3;
 
 /// Stateful decryptor object for unauthenticated SSH symmetric ciphers.
 ///
@@ -46,7 +44,13 @@ enum Inner {
 }
 
 impl Decryptor {
-    /// Create a new decryptor object with the given [`Cipher`], key, and IV.
+    /// Create a new decryptor object with the given [`Cipher`], `key`, and `iv` (i.e.
+    /// initialization vector).
+    ///
+    /// # Errors
+    /// - Returns [`Error::Length`] if `key` or `iv` are the wrong length for the given `cipher`.
+    /// - Returns [`Error::UnsupportedCipher`] if support for the given `cipher` is not enabled
+    ///   in the crate features.
     pub fn new(cipher: Cipher, key: &[u8], iv: &[u8]) -> Result<Self> {
         cipher.check_key_and_iv(key, iv)?;
 
@@ -73,6 +77,7 @@ impl Decryptor {
     }
 
     /// Get the cipher for this decryptor.
+    #[must_use]
     pub fn cipher(&self) -> Cipher {
         match &self.inner {
             #[cfg(feature = "aes-cbc")]
@@ -94,6 +99,7 @@ impl Decryptor {
 
     /// Decrypt the given buffer in place.
     ///
+    /// # Errors
     /// Returns [`Error::Length`] in the event that `buffer` is not a multiple of the cipher's
     /// block size.
     pub fn decrypt(&mut self, buffer: &mut [u8]) -> Result<()> {
@@ -120,6 +126,14 @@ impl Decryptor {
     }
 }
 
+impl Debug for Decryptor {
+    fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
+        f.debug_struct("Decryptor")
+            .field("cipher", &self.cipher())
+            .finish_non_exhaustive()
+    }
+}
+
 /// CBC mode decryption helper which assumes the input is unpadded and block-aligned.
 #[cfg(any(feature = "aes-cbc", feature = "tdes"))]
 fn cbc_decrypt<C>(decryptor: &mut cbc::Decryptor<C>, buffer: &mut [u8]) -> Result<()>

ssh-cipher/src/encryptor.rs

@@ -2,22 +2,20 @@
 
 use crate::{Cipher, Error, Result};
 use cipher::{Block, BlockCipherEncrypt, KeyIvInit};
+use core::fmt::{self, Debug};
 
+#[cfg(any(feature = "aes-cbc", feature = "aes-ctr"))]
+use aes::{Aes128, Aes192, Aes256};
+#[cfg(any(feature = "aes-cbc", feature = "tdes"))]
+use cipher::block::BlockModeEncrypt;
+#[cfg(feature = "tdes")]
+use des::TdesEde3;
 #[cfg(feature = "aes-ctr")]
 use {
     crate::Ctr128BE,
     cipher::{BlockSizeUser, StreamCipherCore, array::sizes::U16},
 };
 
-#[cfg(feature = "tdes")]
-use des::TdesEde3;
-
-#[cfg(any(feature = "aes-cbc", feature = "aes-ctr"))]
-use aes::{Aes128, Aes192, Aes256};
-
-#[cfg(any(feature = "aes-cbc", feature = "tdes"))]
-use cipher::block::BlockModeEncrypt;
-
 /// Stateful encryptor object for unauthenticated SSH symmetric ciphers.
 ///
 /// Note that this deliberately does not support AEAD modes such as AES-GCM and ChaCha20Poly1305,
@@ -46,7 +44,13 @@ enum Inner {
 }
 
 impl Encryptor {
-    /// Create a new encryptor object with the given [`Cipher`], key, and IV.
+    /// Create a new encryptor object with the given [`Cipher`], `key`, and `iv` (i.e.
+    /// initialization vector).
+    ///
+    /// # Errors
+    /// - Returns [`Error::Length`] if `key` or `iv` are the wrong length for the given `cipher`.
+    /// - Returns [`Error::UnsupportedCipher`] if support for the given `cipher` is not enabled
+    ///   in the crate features.
     pub fn new(cipher: Cipher, key: &[u8], iv: &[u8]) -> Result<Self> {
         cipher.check_key_and_iv(key, iv)?;
 
@@ -73,6 +77,7 @@ impl Encryptor {
     }
 
     /// Get the cipher for this encryptor.
+    #[must_use]
     pub fn cipher(&self) -> Cipher {
         match &self.inner {
             #[cfg(feature = "aes-cbc")]
@@ -94,6 +99,7 @@ impl Encryptor {
 
     /// Encrypt the given buffer in place.
     ///
+    /// # Errors
     /// Returns [`Error::Length`] in the event that `buffer` is not a multiple of the cipher's
     /// block size.
     pub fn encrypt(&mut self, buffer: &mut [u8]) -> Result<()> {
@@ -118,6 +124,14 @@ impl Encryptor {
     }
 }
 
+impl Debug for Encryptor {
+    fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
+        f.debug_struct("Encryptor")
+            .field("cipher", &self.cipher())
+            .finish_non_exhaustive()
+    }
+}
+
 /// CBC mode encryption helper which assumes the input is unpadded and block-aligned.
 #[cfg(any(feature = "aes-cbc", feature = "tdes"))]
 fn cbc_encrypt<C>(encryptor: &mut cbc::Encryptor<C>, buffer: &mut [u8]) -> Result<()>

ssh-cipher/src/lib.rs

@@ -1,25 +1,10 @@
 #![no_std]
-#![cfg_attr(docsrs, feature(doc_auto_cfg))]
+#![cfg_attr(docsrs, feature(doc_cfg))]
 #![doc = include_str!("../README.md")]
 #![doc(
     html_logo_url = "https://raw.githubusercontent.com/RustCrypto/media/6ee8e381/logo.svg",
     html_favicon_url = "https://raw.githubusercontent.com/RustCrypto/media/6ee8e381/logo.svg"
 )]
-#![forbid(unsafe_code)]
-#![warn(
-    clippy::alloc_instead_of_core,
-    clippy::arithmetic_side_effects,
-    clippy::mod_module_files,
-    clippy::panic,
-    clippy::panic_in_result_fn,
-    clippy::std_instead_of_alloc,
-    clippy::std_instead_of_core,
-    clippy::unwrap_used,
-    missing_docs,
-    rust_2018_idioms,
-    unused_lifetimes,
-    unused_qualifications
-)]
 
 mod error;
 
@@ -138,12 +123,25 @@ impl Cipher {
     /// Decode cipher algorithm from the given `ciphername`.
     ///
     /// # Supported cipher names
-    /// - `aes256-ctr`
+    /// `aes128-cbc`
+    /// `aes192-cbc`
+    /// `aes256-cbc`
+    /// `aes128-ctr`
+    /// `aes192-ctr`
+    /// `aes256-ctr`
+    /// `aes128-gcm@openssh.com`
+    /// `aes256-gcm@openssh.com`
+    /// `chacha20-poly1305@openssh.com`
+    /// `3des-cbc`
+    ///
+    /// # Errors
+    /// Returns [`LabelError`] if the provided `ciphername` is unknown.
     pub fn new(ciphername: &str) -> core::result::Result<Self, LabelError> {
         ciphername.parse()
     }
 
     /// Get the string identifier which corresponds to this algorithm.
+    #[must_use]
     pub fn as_str(self) -> &'static str {
         match self {
             Self::None => "none",
@@ -161,6 +159,7 @@ impl Cipher {
     }
 
     /// Get the key and IV size for this cipher in bytes.
+    #[must_use]
     pub fn key_and_iv_size(self) -> Option<(usize, usize)> {
         match self {
             Self::None => None,
@@ -178,6 +177,7 @@ impl Cipher {
     }
 
     /// Get the block size for this cipher in bytes.
+    #[must_use]
     pub fn block_size(self) -> usize {
         match self {
             Self::None | Self::ChaCha20Poly1305 | Self::TDesCbc => 8,
@@ -195,14 +195,20 @@ impl Cipher {
     /// Compute the length of padding necessary to pad the given input to
     /// the block size.
     #[allow(clippy::arithmetic_side_effects)]
+    #[must_use]
     pub fn padding_len(self, input_size: usize) -> usize {
+        #[allow(
+            clippy::integer_division_remainder_used,
+            reason = "input_size is non-secret"
+        )]
         match input_size % self.block_size() {
             0 => 0,
             input_rem => self.block_size() - input_rem,
         }
     }
 
     /// Does this cipher have an authentication tag? (i.e. is it an AEAD mode?)
+    #[must_use]
     pub fn has_tag(self) -> bool {
         matches!(
             self,
@@ -211,17 +217,20 @@ impl Cipher {
     }
 
     /// Is this cipher `none`?
+    #[must_use]
     pub fn is_none(self) -> bool {
         self == Self::None
     }
 
     /// Is the cipher anything other than `none`?
+    #[must_use]
     pub fn is_some(self) -> bool {
         !self.is_none()
     }
 
     /// Decrypt the ciphertext in the `buffer` in-place using this cipher.
     ///
+    /// # Errors
     /// Returns [`Error::Length`] in the event that `buffer` is not a multiple of the cipher's
     /// block size.
     #[cfg_attr(
@@ -280,13 +289,17 @@ impl Cipher {
     ///
     /// Only applicable to unauthenticated modes (e.g. AES-CBC, AES-CTR). Not usable with
     /// authenticated modes which are inherently one-shot (AES-GCM, ChaCha20Poly1305).
+    ///
+    /// # Errors
+    /// Propagates errors from [`Decryptor::new`].
     #[cfg(any(feature = "aes-cbc", feature = "aes-ctr", feature = "tdes"))]
     pub fn decryptor(self, key: &[u8], iv: &[u8]) -> Result<Decryptor> {
         Decryptor::new(self, key, iv)
     }
 
     /// Encrypt the ciphertext in the `buffer` in-place using this cipher.
     ///
+    /// # Errors
     /// Returns [`Error::Length`] in the event that `buffer` is not a multiple of the cipher's
     /// block size.
     #[cfg_attr(
@@ -339,6 +352,9 @@ impl Cipher {
     ///
     /// Only applicable to unauthenticated modes (e.g. AES-CBC, AES-CTR). Not usable with
     /// authenticated modes which are inherently one-shot (AES-GCM, ChaCha20Poly1305).
+    ///
+    /// # Errors
+    /// Propagates errors from [`Encryptor::new`].
     #[cfg(any(feature = "aes-cbc", feature = "aes-ctr", feature = "tdes"))]
     pub fn encryptor(self, key: &[u8], iv: &[u8]) -> Result<Encryptor> {
         Encryptor::new(self, key, iv)

ssh-cipher/tests/lib.rs

@@ -1,5 +1,6 @@
-/// Integration tests for `ssh-cipher`.
+//! Integration tests for `ssh-cipher`.
 // TODO(tarcieri): test vectors for each supported cipher
+
 use ssh_cipher::Cipher;
 
 #[test]