From 63a93bc0e6669088877830db1646a90aa53ff703 Mon Sep 17 00:00:00 2001
From: Alex Gaynor <alex.gaynor@gmail.com>
Date: Fri, 31 Jan 2025 12:32:42 -0800
Subject: [PATCH] Added PBKDF1, for use in #12296 (#12369)

---
 src/rust/cryptography-crypto/src/lib.rs    |   1 +
 src/rust/cryptography-crypto/src/pbkdf1.rs | 101 +++++++++++++++++++++
 2 files changed, 102 insertions(+)
 create mode 100644 src/rust/cryptography-crypto/src/pbkdf1.rs

diff --git a/src/rust/cryptography-crypto/src/lib.rs b/src/rust/cryptography-crypto/src/lib.rs
index 066e2f4bb22d..553ef311b6d7 100644
--- a/src/rust/cryptography-crypto/src/lib.rs
+++ b/src/rust/cryptography-crypto/src/lib.rs
@@ -2,4 +2,5 @@
 // 2.0, and the BSD License. See the LICENSE file in the root of this repository
 // for complete details.
 
+pub mod pbkdf1;
 pub mod pkcs12;
diff --git a/src/rust/cryptography-crypto/src/pbkdf1.rs b/src/rust/cryptography-crypto/src/pbkdf1.rs
new file mode 100644
index 000000000000..9a0cda4a116a
--- /dev/null
+++ b/src/rust/cryptography-crypto/src/pbkdf1.rs
@@ -0,0 +1,101 @@
+// This file is dual licensed under the terms of the Apache License, Version
+// 2.0, and the BSD License. See the LICENSE file in the root of this repository
+// for complete details.
+
+/// This is the OpenSSL KDF that's used in decrypting PEM blocks. It is a
+/// generalization of PBKDF1.
+pub fn openssl_kdf(
+    hash_alg: openssl::hash::MessageDigest,
+    password: &[u8],
+    salt: [u8; 8],
+    length: usize,
+) -> Result<Vec<u8>, openssl::error::ErrorStack> {
+    let mut key = Vec::with_capacity(length);
+
+    while key.len() < length {
+        let mut h = openssl::hash::Hasher::new(hash_alg)?;
+
+        if !key.is_empty() {
+            h.update(&key[key.len() - hash_alg.size()..])?;
+        }
+
+        h.update(password)?;
+        h.update(&salt)?;
+
+        let digest = h.finish()?;
+        let size = digest.len().min(length - key.len());
+        key.extend_from_slice(&digest[..size]);
+    }
+
+    Ok(key)
+}
+
+#[cfg(test)]
+mod tests {
+    use super::openssl_kdf;
+
+    #[test]
+    fn test_openssl_kdf() {
+        for (md, password, salt, expected) in [
+            (
+                openssl::hash::MessageDigest::md5(),
+                b"password123" as &[u8],
+                [0x01, 0x02, 0x03, 0x04, 0x05, 0x06, 0x07, 0x08],
+                &[
+                    0x31, 0xcc, 0x91, 0x39, 0x80, 0x69, 0x98, 0xb2, 0xaa, 0xc3, 0x66, 0xcf, 0x40,
+                    0x1b, 0x49, 0xdc, 0x0d, 0x37, 0xbd, 0x5c, 0x22, 0x52, 0xc7, 0xcb,
+                ][..],
+            ),
+            (
+                openssl::hash::MessageDigest::md5(),
+                b"diffpassword",
+                [0xaa, 0xbb, 0xcc, 0xdd, 0xee, 0xff, 0x11, 0x22],
+                &[
+                    0x89, 0x9b, 0x70, 0x37, 0xdb, 0x29, 0x42, 0x69, 0xdb, 0x4d, 0x67, 0xb9, 0x81,
+                    0x67, 0xa7, 0x59, 0xfd, 0xec, 0x5d, 0x0f, 0x57, 0x52, 0xef, 0x04,
+                ],
+            ),
+            (
+                openssl::hash::MessageDigest::md5(),
+                b"secret_key",
+                [0x11, 0x22, 0x33, 0x44, 0x55, 0x66, 0x77, 0x88],
+                &[
+                    0xa1, 0x98, 0x00, 0xf9, 0xab, 0x97, 0x36, 0xa1, 0x83, 0x4a, 0x19, 0x76, 0x47,
+                    0x25, 0xda, 0x9b,
+                ],
+            ),
+            (
+                openssl::hash::MessageDigest::md5(),
+                b"another_password",
+                [0x99, 0xaa, 0xbb, 0xcc, 0xdd, 0xee, 0xff, 0x00],
+                &[
+                    0xc2, 0x09, 0x35, 0x72, 0xe5, 0x62, 0xd4, 0xba, 0x90, 0x4a, 0x5f, 0x46, 0x7f,
+                    0x27, 0xd2, 0x6c,
+                ],
+            ),
+            (
+                openssl::hash::MessageDigest::md5(),
+                b"very_long_and_complex_password",
+                [0x01, 0x23, 0x45, 0x67, 0x89, 0xab, 0xcd, 0xef],
+                &[
+                    0x1c, 0x5d, 0xdf, 0xa2, 0xca, 0xca, 0x41, 0xa4, 0xc9, 0xb4, 0x31, 0xd2, 0x9f,
+                    0x04, 0x46, 0x81, 0xd2, 0x2b, 0x4e, 0x40, 0x06, 0x41, 0x5d, 0x37, 0x20, 0xef,
+                    0x01, 0x1d, 0xc7, 0x8a, 0x16, 0xb5,
+                ],
+            ),
+            (
+                openssl::hash::MessageDigest::md5(),
+                b"different_secure_password",
+                [0xfe, 0xdc, 0xba, 0x98, 0x76, 0x54, 0x32, 0x10],
+                &[
+                    0xca, 0x08, 0xce, 0xb2, 0x46, 0x8f, 0xdc, 0x72, 0x83, 0xc7, 0x0b, 0x8a, 0xd0,
+                    0x94, 0x54, 0x2b, 0x22, 0xd5, 0x1f, 0xf2, 0x5d, 0x0c, 0x1d, 0x99, 0xf3, 0x2f,
+                    0x54, 0xa8, 0x68, 0x95, 0x13, 0xbd,
+                ],
+            ),
+        ] {
+            let key = openssl_kdf(md, password, salt, expected.len()).unwrap();
+            assert_eq!(key, expected);
+        }
+    }
+}