RSA PKCS1 v1.5 Encryption Support (#492)

aws-lc-rs-testing/tests/rsa_test.rs

@@ -0,0 +1,57 @@
+// Copyright Amazon.com, Inc. or its affiliates. All Rights Reserved.
+// SPDX-License-Identifier: Apache-2.0 OR ISC
+
+use aws_lc_rs::rsa::{
+    Pkcs1PrivateDecryptingKey, Pkcs1PublicEncryptingKey, PrivateDecryptingKey, PublicEncryptingKey,
+};
+use openssl::rsa::{Padding, Rsa};
+
+#[test]
+fn rsa2048_pkcs1_openssl_interop() {
+    const PKCS8_PRIVATE_KEY: &[u8] =
+        include_bytes!("../../aws-lc-rs/tests/data/rsa_test_private_key_2048.p8");
+    const RSA_PRIVATE_KEY: &[u8] =
+        include_bytes!("../../aws-lc-rs/tests/data/rsa_test_private_key_2048.der");
+    const PUBLIC_KEY: &[u8] =
+        include_bytes!("../../aws-lc-rs/tests/data/rsa_test_public_key_2048.x509");
+    const MESSAGE: &[u8] = b"OpenSSL KAT";
+
+    let aws_public_key = PublicEncryptingKey::from_der(PUBLIC_KEY).expect("public key");
+    let aws_public_key = Pkcs1PublicEncryptingKey::new(aws_public_key).expect("public key");
+
+    let mut ciphertext = vec![0u8; aws_public_key.ciphertext_size()];
+    let ciphertext: &[u8] = aws_public_key
+        .encrypt(MESSAGE, &mut ciphertext)
+        .expect("encrypted");
+
+    assert_ne!(MESSAGE, ciphertext);
+
+    let ossl_private_key = Rsa::private_key_from_der(RSA_PRIVATE_KEY).expect("private key");
+
+    let mut message = vec![0u8; ossl_private_key.size().try_into().expect("usize cast")];
+    let message_len = ossl_private_key
+        .private_decrypt(ciphertext, &mut message, Padding::PKCS1)
+        .expect("decrypted");
+    let message: &[u8] = &message[0..message_len];
+
+    assert_eq!(MESSAGE, message);
+
+    let aws_private_key = PrivateDecryptingKey::from_pkcs8(PKCS8_PRIVATE_KEY).expect("private key");
+    let aws_private_key = Pkcs1PrivateDecryptingKey::new(aws_private_key).expect("private key");
+    let ossl_public_key = Rsa::public_key_from_der(PUBLIC_KEY).expect("public key");
+
+    let mut ciphertext = vec![0u8; ossl_public_key.size().try_into().expect("usize cast")];
+    let ciphertext_len = ossl_public_key
+        .public_encrypt(MESSAGE, &mut ciphertext, Padding::PKCS1)
+        .expect("encrypted");
+    let ciphertext: &[u8] = &ciphertext[0..ciphertext_len];
+
+    assert_ne!(MESSAGE, ciphertext);
+
+    let mut plaintext = vec![0u8; aws_private_key.min_output_size()];
+    let plaintext: &[u8] = aws_private_key
+        .decrypt(ciphertext, &mut plaintext)
+        .expect("decrypted");
+
+    assert_eq!(MESSAGE, plaintext);
+}

aws-lc-rs/src/rsa.rs

@@ -78,6 +78,7 @@ pub use self::{
             OaepAlgorithm, OaepPrivateDecryptingKey, OaepPublicEncryptingKey, OAEP_SHA1_MGF1SHA1,
             OAEP_SHA256_MGF1SHA256, OAEP_SHA384_MGF1SHA384, OAEP_SHA512_MGF1SHA512,
         },
+        pkcs1::{Pkcs1PrivateDecryptingKey, Pkcs1PublicEncryptingKey},
         EncryptionAlgorithmId, PrivateDecryptingKey, PublicEncryptingKey,
     },
     key::{KeyPair, KeySize, PublicKey, PublicKeyComponents},

aws-lc-rs/src/rsa/encryption.rs

@@ -2,6 +2,7 @@
 // SPDX-License-Identifier: Apache-2.0 OR ISC
 
 pub(super) mod oaep;
+pub(super) mod pkcs1;
 
 use super::{
     encoding,

aws-lc-rs/src/rsa/encryption/pkcs1.rs

@@ -0,0 +1,187 @@
+// Copyright Amazon.com, Inc. or its affiliates. All Rights Reserved.
+// SPDX-License-Identifier: Apache-2.0 OR ISC
+
+#![allow(clippy::module_name_repetitions)]
+
+use super::{PrivateDecryptingKey, PublicEncryptingKey};
+use crate::{error::Unspecified, fips::indicator_check, ptr::LcPtr};
+use aws_lc::{
+    EVP_PKEY_CTX_new, EVP_PKEY_CTX_set_rsa_padding, EVP_PKEY_decrypt, EVP_PKEY_decrypt_init,
+    EVP_PKEY_encrypt, EVP_PKEY_encrypt_init, EVP_PKEY_CTX, RSA_PKCS1_PADDING,
+};
+use core::{fmt::Debug, ptr::null_mut};
+
+/// RSA PKCS1-v1.5 public key for encryption.
+pub struct Pkcs1PublicEncryptingKey {
+    public_key: PublicEncryptingKey,
+}
+
+impl Pkcs1PublicEncryptingKey {
+    /// Constructs an `Pkcs1PublicEncryptingKey` from a `PublicEncryptingKey`.
+    /// # Errors
+    /// * `Unspecified`: Any error that occurs while attempting to construct an RSA-OAEP public key.
+    pub fn new(public_key: PublicEncryptingKey) -> Result<Self, Unspecified> {
+        Ok(Self { public_key })
+    }
+
+    /// Encrypts the contents in `plaintext` and writes the corresponding ciphertext to `ciphertext`.
+    /// Returns the subslice of `ciphertext` containing the ciphertext output.
+    ///
+    /// # Max Plaintext Length
+    /// The provided length of `plaintext` must be at most [`Self::max_plaintext_size`].
+    ///
+    /// # Sizing `output`
+    /// The length of `output` must be greater than or equal to [`Self::ciphertext_size`].
+    ///
+    /// # Errors
+    /// * `Unspecified` for any error that occurs while encrypting `plaintext`.
+    pub fn encrypt<'ciphertext>(
+        &self,
+        plaintext: &[u8],
+        ciphertext: &'ciphertext mut [u8],
+    ) -> Result<&'ciphertext mut [u8], Unspecified> {
+        let pkey_ctx = LcPtr::new(unsafe { EVP_PKEY_CTX_new(*self.public_key.0, null_mut()) })?;
+
+        if 1 != unsafe { EVP_PKEY_encrypt_init(*pkey_ctx) } {
+            return Err(Unspecified);
+        }
+
+        configure_pkcs1_crypto_operation(&pkey_ctx)?;
+
+        let mut out_len = ciphertext.len();
+
+        if 1 != indicator_check!(unsafe {
+            EVP_PKEY_encrypt(
+                *pkey_ctx,
+                ciphertext.as_mut_ptr(),
+                &mut out_len,
+                plaintext.as_ptr(),
+                plaintext.len(),
+            )
+        }) {
+            return Err(Unspecified);
+        };
+
+        Ok(&mut ciphertext[..out_len])
+    }
+
+    /// Returns the RSA key size in bytes.
+    #[must_use]
+    pub fn key_size_bytes(&self) -> usize {
+        self.public_key.key_size_bytes()
+    }
+
+    /// Returns the RSA key size in bits.
+    #[must_use]
+    pub fn key_size_bits(&self) -> usize {
+        self.public_key.key_size_bits()
+    }
+
+    /// Returns the max plaintext that could be encrypted using this key.
+    #[must_use]
+    pub fn max_plaintext_size(&self) -> usize {
+        const RSA_PKCS1_PADDING_SIZE: usize = 11; // crypto/fipsmodule/rsa/internal.h
+        self.key_size_bytes() - RSA_PKCS1_PADDING_SIZE
+    }
+
+    /// Returns the max ciphertext size that will be output by `Self::encrypt`.
+    #[must_use]
+    pub fn ciphertext_size(&self) -> usize {
+        self.key_size_bytes()
+    }
+}
+
+impl Debug for Pkcs1PublicEncryptingKey {
+    fn fmt(&self, f: &mut core::fmt::Formatter<'_>) -> core::fmt::Result {
+        f.debug_struct("Pkcs1PublicEncryptingKey")
+            .finish_non_exhaustive()
+    }
+}
+
+/// RSA PKCS1-v1.5 private key for decryption.
+pub struct Pkcs1PrivateDecryptingKey {
+    private_key: PrivateDecryptingKey,
+}
+
+impl Pkcs1PrivateDecryptingKey {
+    /// Constructs an `Pkcs1PrivateDecryptingKey` from a `PrivateDecryptingKey`.
+    /// # Errors
+    /// * `Unspecified`: Any error that occurs while attempting to construct an RSA-OAEP public key.
+    pub fn new(private_key: PrivateDecryptingKey) -> Result<Self, Unspecified> {
+        Ok(Self { private_key })
+    }
+
+    /// Decrypts the contents in `ciphertext` and writes the corresponding plaintext to `plaintext`.
+    /// Returns the subslice of `plaintext` containing the plaintext output.
+    ///
+    /// # Max Ciphertext Length
+    /// The provided length of `ciphertext` must be [`Self::key_size_bytes`].
+    ///
+    /// # Sizing `output`
+    /// The length of `output` must be greater than or equal to [`Self::min_output_size`].
+    ///
+    /// # Errors
+    /// * `Unspecified` for any error that occurs while decrypting `ciphertext`.
+    pub fn decrypt<'plaintext>(
+        &self,
+        ciphertext: &[u8],
+        plaintext: &'plaintext mut [u8],
+    ) -> Result<&'plaintext mut [u8], Unspecified> {
+        let pkey_ctx = LcPtr::new(unsafe { EVP_PKEY_CTX_new(*self.private_key.0, null_mut()) })?;
+
+        if 1 != unsafe { EVP_PKEY_decrypt_init(*pkey_ctx) } {
+            return Err(Unspecified);
+        }
+
+        configure_pkcs1_crypto_operation(&pkey_ctx)?;
+
+        let mut out_len = plaintext.len();
+
+        if 1 != indicator_check!(unsafe {
+            EVP_PKEY_decrypt(
+                *pkey_ctx,
+                plaintext.as_mut_ptr(),
+                &mut out_len,
+                ciphertext.as_ptr(),
+                ciphertext.len(),
+            )
+        }) {
+            return Err(Unspecified);
+        };
+
+        Ok(&mut plaintext[..out_len])
+    }
+
+    /// Returns the RSA key size in bytes.
+    #[must_use]
+    pub fn key_size_bytes(&self) -> usize {
+        self.private_key.key_size_bytes()
+    }
+
+    /// Returns the RSA key size in bits.
+    #[must_use]
+    pub fn key_size_bits(&self) -> usize {
+        self.private_key.key_size_bits()
+    }
+
+    /// Returns the minimum plaintext buffer size required for `Self::decrypt`.
+    #[must_use]
+    pub fn min_output_size(&self) -> usize {
+        self.key_size_bytes()
+    }
+}
+
+impl Debug for Pkcs1PrivateDecryptingKey {
+    fn fmt(&self, f: &mut core::fmt::Formatter<'_>) -> core::fmt::Result {
+        f.debug_struct("Pkcs1PrivateDecryptingKey")
+            .finish_non_exhaustive()
+    }
+}
+
+fn configure_pkcs1_crypto_operation(evp_pkey_ctx: &LcPtr<EVP_PKEY_CTX>) -> Result<(), Unspecified> {
+    if 1 != unsafe { EVP_PKEY_CTX_set_rsa_padding(**evp_pkey_ctx, RSA_PKCS1_PADDING) } {
+        return Err(Unspecified);
+    };
+
+    Ok(())
+}