refactor(ext/crypto): cleanup decrypt code (#13120)

1 files changed, 155 insertions, 0 deletions

diff --git a/ext/crypto/decrypt.rs b/ext/crypto/decrypt.rs
new file mode 100644
index 000000000..f487d7e34
--- /dev/null
+++ b/ext/crypto/decrypt.rs
@@ -0,0 +1,155 @@
+use std::cell::RefCell;
+use std::rc::Rc;
+
+use crate::shared::*;
+use block_modes::BlockMode;
+use deno_core::error::custom_error;
+use deno_core::error::AnyError;
+use deno_core::OpState;
+use deno_core::ZeroCopyBuf;
+use rsa::pkcs1::FromRsaPrivateKey;
+use rsa::PaddingScheme;
+use serde::Deserialize;
+use sha1::Digest;
+use sha1::Sha1;
+use sha2::Sha256;
+use sha2::Sha384;
+use sha2::Sha512;
+
+#[derive(Deserialize)]
+#[serde(rename_all = "camelCase")]
+pub struct DecryptOptions {
+  key: RawKeyData,
+  #[serde(flatten)]
+  algorithm: DecryptAlgorithm,
+}
+
+#[derive(Deserialize)]
+#[serde(rename_all = "camelCase", tag = "algorithm")]
+pub enum DecryptAlgorithm {
+  #[serde(rename = "RSA-OAEP")]
+  RsaOaep {
+    hash: ShaHash,
+    #[serde(with = "serde_bytes")]
+    label: Vec<u8>,
+  },
+  #[serde(rename = "AES-CBC", rename_all = "camelCase")]
+  AesCbc {
+    #[serde(with = "serde_bytes")]
+    iv: Vec<u8>,
+    length: usize,
+  },
+}
+
+pub async fn op_crypto_decrypt(
+  _state: Rc<RefCell<OpState>>,
+  opts: DecryptOptions,
+  data: ZeroCopyBuf,
+) -> Result<ZeroCopyBuf, AnyError> {
+  let key = opts.key;
+  let fun = move || match opts.algorithm {
+    DecryptAlgorithm::RsaOaep { hash, label } => {
+      decrypt_rsa_oaep(key, hash, label, &data)
+    }
+    DecryptAlgorithm::AesCbc { iv, length } => {
+      decrypt_aes_cbc(key, length, iv, &data)
+    }
+  };
+  let buf = tokio::task::spawn_blocking(fun).await.unwrap()?;
+  Ok(buf.into())
+}
+
+fn decrypt_rsa_oaep(
+  key: RawKeyData,
+  hash: ShaHash,
+  label: Vec<u8>,
+  data: &[u8],
+) -> Result<Vec<u8>, deno_core::anyhow::Error> {
+  let key = key.as_rsa_private_key()?;
+
+  let private_key = rsa::RsaPrivateKey::from_pkcs1_der(key)?;
+  let label = Some(String::from_utf8_lossy(&label).to_string());
+
+  let padding = match hash {
+    ShaHash::Sha1 => PaddingScheme::OAEP {
+      digest: Box::new(Sha1::new()),
+      mgf_digest: Box::new(Sha1::new()),
+      label,
+    },
+    ShaHash::Sha256 => PaddingScheme::OAEP {
+      digest: Box::new(Sha256::new()),
+      mgf_digest: Box::new(Sha256::new()),
+      label,
+    },
+    ShaHash::Sha384 => PaddingScheme::OAEP {
+      digest: Box::new(Sha384::new()),
+      mgf_digest: Box::new(Sha384::new()),
+      label,
+    },
+    ShaHash::Sha512 => PaddingScheme::OAEP {
+      digest: Box::new(Sha512::new()),
+      mgf_digest: Box::new(Sha512::new()),
+      label,
+    },
+  };
+
+  private_key
+    .decrypt(padding, data)
+    .map_err(|e| custom_error("DOMExceptionOperationError", e.to_string()))
+}
+
+fn decrypt_aes_cbc(
+  key: RawKeyData,
+  length: usize,
+  iv: Vec<u8>,
+  data: &[u8],
+) -> Result<Vec<u8>, deno_core::anyhow::Error> {
+  let key = key.as_secret_key()?;
+
+  // 2.
+  let plaintext = match length {
+    128 => {
+      // Section 10.3 Step 2 of RFC 2315 https://www.rfc-editor.org/rfc/rfc2315
+      type Aes128Cbc =
+        block_modes::Cbc<aes::Aes128, block_modes::block_padding::Pkcs7>;
+      let cipher = Aes128Cbc::new_from_slices(key, &iv)?;
+
+      cipher.decrypt_vec(data).map_err(|_| {
+        custom_error(
+          "DOMExceptionOperationError",
+          "Decryption failed".to_string(),
+        )
+      })?
+    }
+    192 => {
+      // Section 10.3 Step 2 of RFC 2315 https://www.rfc-editor.org/rfc/rfc2315
+      type Aes192Cbc =
+        block_modes::Cbc<aes::Aes192, block_modes::block_padding::Pkcs7>;
+      let cipher = Aes192Cbc::new_from_slices(key, &iv)?;
+
+      cipher.decrypt_vec(data).map_err(|_| {
+        custom_error(
+          "DOMExceptionOperationError",
+          "Decryption failed".to_string(),
+        )
+      })?
+    }
+    256 => {
+      // Section 10.3 Step 2 of RFC 2315 https://www.rfc-editor.org/rfc/rfc2315
+      type Aes256Cbc =
+        block_modes::Cbc<aes::Aes256, block_modes::block_padding::Pkcs7>;
+      let cipher = Aes256Cbc::new_from_slices(key, &iv)?;
+
+      cipher.decrypt_vec(data).map_err(|_| {
+        custom_error(
+          "DOMExceptionOperationError",
+          "Decryption failed".to_string(),
+        )
+      })?
+    }
+    _ => unreachable!(),
+  };
+
+  // 6.
+  Ok(plaintext)
+}