From ea22440767854966ab9d2ae32447a33c52f54f65 Mon Sep 17 00:00:00 2001
From: Tony Arcieri <bascule@gmail.com>
Date: Wed, 5 Jun 2024 19:00:23 -0600
Subject: [PATCH] pkcs8: use `pbes2::Parameters::recommended`

When encrypting private keys, uses the recommended set of parameters
from the `pbes2` crate.

This uses scrypt with parameters explicitly selected to be compatible
with OpenSSL so it's capable of decrypting keys encrypted using the
`pkcs8` crate.

Closes #429
---
 pkcs8/Cargo.toml                        |  2 +-
 pkcs8/src/encrypted_private_key_info.rs | 15 +++------------
 pkcs8/src/private_key_info.rs           |  7 ++-----
 pkcs8/src/traits.rs                     |  9 +++------
 4 files changed, 9 insertions(+), 24 deletions(-)

diff --git a/pkcs8/Cargo.toml b/pkcs8/Cargo.toml
index aa1dc46aa..43606ee3f 100644
--- a/pkcs8/Cargo.toml
+++ b/pkcs8/Cargo.toml
@@ -22,7 +22,7 @@ spki = { version = "=0.8.0-pre.0" }
 
 # optional dependencies
 rand_core = { version = "0.6", optional = true, default-features = false }
-pkcs5 = { version = "=0.8.0-pre.0", optional = true }
+pkcs5 = { version = "=0.8.0-pre.0", optional = true, features = ["rand_core"] }
 subtle = { version = "2", optional = true, default-features = false }
 
 [dev-dependencies]
diff --git a/pkcs8/src/encrypted_private_key_info.rs b/pkcs8/src/encrypted_private_key_info.rs
index 12fafdf21..19575bf2f 100644
--- a/pkcs8/src/encrypted_private_key_info.rs
+++ b/pkcs8/src/encrypted_private_key_info.rs
@@ -12,10 +12,7 @@ use pkcs5::EncryptionScheme;
 use der::SecretDocument;
 
 #[cfg(feature = "encryption")]
-use {
-    pkcs5::pbes2,
-    rand_core::{CryptoRng, RngCore},
-};
+use {pkcs5::pbes2, rand_core::CryptoRngCore};
 
 #[cfg(feature = "pem")]
 use der::pem::PemLabel;
@@ -64,17 +61,11 @@ impl<'a> EncryptedPrivateKeyInfo<'a> {
     /// derived from the provided password.
     #[cfg(feature = "encryption")]
     pub(crate) fn encrypt(
-        mut rng: impl CryptoRng + RngCore,
+        rng: &mut impl CryptoRngCore,
         password: impl AsRef<[u8]>,
         doc: &[u8],
     ) -> Result<SecretDocument> {
-        let mut salt = [0u8; 16];
-        rng.fill_bytes(&mut salt);
-
-        let mut iv = [0u8; 16];
-        rng.fill_bytes(&mut iv);
-
-        let pbes2_params = pbes2::Parameters::scrypt_aes256cbc(Default::default(), &salt, iv)?;
+        let pbes2_params = pbes2::Parameters::recommended(rng);
         EncryptedPrivateKeyInfo::encrypt_with(pbes2_params, password, doc)
     }
 
diff --git a/pkcs8/src/private_key_info.rs b/pkcs8/src/private_key_info.rs
index b3550d619..03b7ca162 100644
--- a/pkcs8/src/private_key_info.rs
+++ b/pkcs8/src/private_key_info.rs
@@ -13,10 +13,7 @@ use der::SecretDocument;
 
 #[cfg(feature = "encryption")]
 use {
-    crate::EncryptedPrivateKeyInfo,
-    der::zeroize::Zeroizing,
-    pkcs5::pbes2,
-    rand_core::{CryptoRng, RngCore},
+    crate::EncryptedPrivateKeyInfo, der::zeroize::Zeroizing, pkcs5::pbes2, rand_core::CryptoRngCore,
 };
 
 #[cfg(feature = "pem")]
@@ -137,7 +134,7 @@ impl<'a> PrivateKeyInfo<'a> {
     #[cfg(feature = "encryption")]
     pub fn encrypt(
         &self,
-        rng: impl CryptoRng + RngCore,
+        rng: &mut impl CryptoRngCore,
         password: impl AsRef<[u8]>,
     ) -> Result<SecretDocument> {
         let der = Zeroizing::new(self.to_der()?);
diff --git a/pkcs8/src/traits.rs b/pkcs8/src/traits.rs
index 9cd4116d6..a38a78e6d 100644
--- a/pkcs8/src/traits.rs
+++ b/pkcs8/src/traits.rs
@@ -6,10 +6,7 @@ use crate::{Error, PrivateKeyInfo, Result};
 use der::SecretDocument;
 
 #[cfg(feature = "encryption")]
-use {
-    crate::EncryptedPrivateKeyInfo,
-    rand_core::{CryptoRng, RngCore},
-};
+use {crate::EncryptedPrivateKeyInfo, rand_core::CryptoRngCore};
 
 #[cfg(feature = "pem")]
 use {
@@ -106,7 +103,7 @@ pub trait EncodePrivateKey {
     #[cfg(feature = "encryption")]
     fn to_pkcs8_encrypted_der(
         &self,
-        rng: impl CryptoRng + RngCore,
+        rng: &mut impl CryptoRngCore,
         password: impl AsRef<[u8]>,
     ) -> Result<SecretDocument> {
         EncryptedPrivateKeyInfo::encrypt(rng, password, self.to_pkcs8_der()?.as_bytes())
@@ -124,7 +121,7 @@ pub trait EncodePrivateKey {
     #[cfg(all(feature = "encryption", feature = "pem"))]
     fn to_pkcs8_encrypted_pem(
         &self,
-        rng: impl CryptoRng + RngCore,
+        rng: &mut impl CryptoRngCore,
         password: impl AsRef<[u8]>,
         line_ending: LineEnding,
     ) -> Result<Zeroizing<String>> {