feat(ext/crypto) - support encrypt/decrypt with AES-CTR

cli/tests/unit/webcrypto_test.ts

@@ -1,4 +1,9 @@
-import { assert, assertEquals, assertRejects } from "./test_util.ts";
+import {
+  assert,
+  assertEquals,
+  assertNotEquals,
+  assertRejects,
+} from "./test_util.ts";
 
 // https://github.com/denoland/deno/issues/11664
 Deno.test(async function testImportArrayBufferKey() {
@@ -608,6 +613,110 @@ Deno.test(async function testAesCbcEncryptDecrypt() {
   assertEquals(new Uint8Array(decrypted), new Uint8Array([1, 2, 3, 4, 5, 6]));
 });
 
+Deno.test(async function testAesCtrEncryptDecrypt() {
+  async function aesCtrRoundTrip(
+    key: CryptoKey,
+    counter: Uint8Array,
+    length: number,
+    plainText: Uint8Array,
+  ) {
+    const cipherText = await crypto.subtle.encrypt(
+      {
+        name: "AES-CTR",
+        counter,
+        length,
+      },
+      key,
+      plainText,
+    );
+
+    assert(cipherText instanceof ArrayBuffer);
+    assertEquals(cipherText.byteLength, plainText.byteLength);
+    assertNotEquals(new Uint8Array(cipherText), plainText);
+
+    const decryptedText = await crypto.subtle.decrypt(
+      {
+        name: "AES-CTR",
+        counter,
+        length,
+      },
+      key,
+      cipherText,
+    );
+
+    assert(decryptedText instanceof ArrayBuffer);
+    assertEquals(decryptedText.byteLength, plainText.byteLength);
+    assertEquals(new Uint8Array(decryptedText), plainText);
+  }
+  for (const keySize of [128, 192, 256]) {
+    const key = await crypto.subtle.generateKey(
+      { name: "AES-CTR", length: keySize },
+      true,
+      ["encrypt", "decrypt"],
+    ) as CryptoKey;
+
+    // test normal operation
+    for (const length of [128 /*, 64, 128 */]) {
+      const counter = await crypto.getRandomValues(new Uint8Array(16));
+
+      await aesCtrRoundTrip(
+        key,
+        counter,
+        length,
+        new Uint8Array([1, 2, 3, 4, 5, 6]),
+      );
+    }
+
+    // test counter-wrapping
+    for (const length of [32, 64, 128]) {
+      const plaintext1 = await crypto.getRandomValues(new Uint8Array(32));
+      const counter = new Uint8Array(16);
+
+      // fixed upper part
+      for (let off = 0; off < 16 - (length / 8); ++off) {
+        counter[off] = off;
+      }
+      const ciphertext1 = await crypto.subtle.encrypt(
+        {
+          name: "AES-CTR",
+          counter,
+          length,
+        },
+        key,
+        plaintext1,
+      );
+
+      // Set lower [length] counter bits to all '1's
+      for (let off = 16 - (length / 8); off < 16; ++off) {
+        counter[off] = 0xff;
+      }
+
+      // = [ 1 block of 0x00 + plaintext1 ]
+      const plaintext2 = new Uint8Array(48);
+      plaintext2.set(plaintext1, 16);
+
+      const ciphertext2 = await crypto.subtle.encrypt(
+        {
+          name: "AES-CTR",
+          counter,
+          length,
+        },
+        key,
+        plaintext2,
+      );
+
+      // If counter wrapped, 2nd block of ciphertext2 should be equal to 1st block of ciphertext1
+      // since ciphertext1 used counter = 0x00...00
+      // and ciphertext2 used counter = 0xFF..FF which should wrap to 0x00..00 without affecting
+      // higher bits
+      assertEquals(
+        new Uint8Array(ciphertext1),
+        new Uint8Array(ciphertext2).slice(16),
+      );
+    }
+  }
+});
+
 // TODO(@littledivy): Enable WPT when we have importKey support
 Deno.test(async function testECDH() {
   const namedCurve = "P-256";

ext/crypto/00_crypto.js

@@ -126,10 +126,12 @@
     "encrypt": {
       "RSA-OAEP": "RsaOaepParams",
       "AES-CBC": "AesCbcParams",
+      "AES-CTR": "AesCtrParams",
     },
     "decrypt": {
       "RSA-OAEP": "RsaOaepParams",
       "AES-CBC": "AesCbcParams",
+      "AES-CTR": "AesCtrParams",
     },
     "get key length": {
       "AES-CBC": "AesDerivedKeyParams",
@@ -605,6 +607,39 @@
           // 6.
           return plainText.buffer;
         }
+        case "AES-CTR": {
+          normalizedAlgorithm.counter = copyBuffer(normalizedAlgorithm.counter);
+
+          // 1.
+          if (normalizedAlgorithm.counter.byteLength !== 16) {
+            throw new DOMException(
+              "Counter vector must be 16 bytes",
+              "OperationError",
+            );
+          }
+
+          // 2.
+          if (
+            normalizedAlgorithm.length === 0 || normalizedAlgorithm.length > 128
+          ) {
+            throw new DOMException(
+              "Counter length must not be 0 or greater than 128",
+              "OperationError",
+            );
+          }
+
+          // 3.
+          const cipherText = await core.opAsync("op_crypto_decrypt", {
+            key: keyData,
+            algorithm: "AES-CTR",
+            keyLength: key[_algorithm].length,
+            counter: normalizedAlgorithm.counter,
+            ctrLength: normalizedAlgorithm.length,
+          }, data);
+
+          // 4.
+          return cipherText.buffer;
+        }
         default:
           throw new DOMException("Not implemented", "NotSupportedError");
       }
@@ -3431,6 +3466,39 @@
         // 4.
         return cipherText.buffer;
       }
+      case "AES-CTR": {
+        normalizedAlgorithm.counter = copyBuffer(normalizedAlgorithm.counter);
+
+        // 1.
+        if (normalizedAlgorithm.counter.byteLength !== 16) {
+          throw new DOMException(
+            "Counter vector must be 16 bytes",
+            "OperationError",
+          );
+        }
+
+        // 2.
+        if (
+          normalizedAlgorithm.length == 0 || normalizedAlgorithm.length > 128
+        ) {
+          throw new DOMException(
+            "Counter length must not be 0 or greater than 128",
+            "OperationError",
+          );
+        }
+
+        // 3.
+        const cipherText = await core.opAsync("op_crypto_encrypt", {
+          key: keyData,
+          algorithm: "AES-CTR",
+          keyLength: key[_algorithm].length,
+          counter: normalizedAlgorithm.counter,
+          ctrLength: normalizedAlgorithm.length,
+        }, data);
+
+        // 4.
+        return cipherText.buffer;
+      }
       default:
         throw new DOMException("Not implemented", "NotSupportedError");
     }

ext/crypto/01_webidl.js

@@ -404,6 +404,24 @@
   webidl.converters.AesCbcParams = webidl
     .createDictionaryConverter("AesCbcParams", dictAesCbcParams);
 
+  const dictAesCtrParams = [
+    ...dictAlgorithm,
+    {
+      key: "counter",
+      converter: webidl.converters["BufferSource"],
+      required: true,
+    },
+    {
+      key: "length",
+      converter: (V, opts) =>
+        webidl.converters["unsigned short"](V, { ...opts, enforceRange: true }),
+      required: true,
+    },
+  ];
+
+  webidl.converters.AesCtrParams = webidl
+    .createDictionaryConverter("AesCtrParams", dictAesCtrParams);
+
   webidl.converters.CryptoKey = webidl.createInterfaceConverter(
     "CryptoKey",
     CryptoKey,

ext/crypto/Cargo.toml

@@ -17,6 +17,7 @@ path = "lib.rs"
 aes = "0.7.5"
 base64 = "0.13.0"
 block-modes = "0.8.1"
+ctr = "0.8.0"
 deno_core = { version = "0.112.0", path = "../../core" }
 deno_web = { version = "0.61.0", path = "../web" }
 elliptic-curve = { version = "0.10.6", features = ["std", "pem"] }

ext/crypto/decrypt.rs

@@ -2,8 +2,18 @@ use std::cell::RefCell;
 use std::rc::Rc;
 
 use crate::shared::*;
+use aes::BlockEncrypt;
+use aes::NewBlockCipher;
 use block_modes::BlockMode;
+use ctr::cipher::NewCipher;
+use ctr::cipher::StreamCipher;
+use ctr::flavors::Ctr128BE;
+use ctr::flavors::Ctr32BE;
+use ctr::flavors::Ctr64BE;
+use ctr::flavors::CtrFlavor;
+use ctr::Ctr;
 use deno_core::error::custom_error;
+use deno_core::error::type_error;
 use deno_core::error::AnyError;
 use deno_core::OpState;
 use deno_core::ZeroCopyBuf;
@@ -39,6 +49,13 @@ pub enum DecryptAlgorithm {
     iv: Vec<u8>,
     length: usize,
   },
+  #[serde(rename = "AES-CTR", rename_all = "camelCase")]
+  AesCtr {
+    #[serde(with = "serde_bytes")]
+    counter: Vec<u8>,
+    ctr_length: usize,
+    key_length: usize,
+  },
 }
 
 pub async fn op_crypto_decrypt(
@@ -54,6 +71,11 @@ pub async fn op_crypto_decrypt(
     DecryptAlgorithm::AesCbc { iv, length } => {
       decrypt_aes_cbc(key, length, iv, &data)
     }
+    DecryptAlgorithm::AesCtr {
+      counter,
+      ctr_length,
+      key_length,
+    } => decrypt_aes_ctr(key, key_length, &counter, ctr_length, &data),
   };
   let buf = tokio::task::spawn_blocking(fun).await.unwrap()?;
   Ok(buf.into())
@@ -153,3 +175,56 @@ fn decrypt_aes_cbc(
   // 6.
   Ok(plaintext)
 }
+
+fn decrypt_aes_ctr_gen<B, F>(
+  key: &[u8],
+  counter: &[u8],
+  data: &[u8],
+) -> Result<Vec<u8>, AnyError>
+where
+  B: BlockEncrypt + NewBlockCipher,
+  F: CtrFlavor<B::BlockSize>,
+{
+  let mut cipher = Ctr::<B, F>::new(key.into(), counter.into());
+
+  let mut plaintext = data.to_vec();
+  cipher
+    .try_apply_keystream(&mut plaintext)
+    .map_err(|_| operation_error("tried to decrypt too much data"))?;
+
+  Ok(plaintext)
+}
+
+fn decrypt_aes_ctr(
+  key: RawKeyData,
+  key_length: usize,
+  counter: &[u8],
+  ctr_length: usize,
+  data: &[u8],
+) -> Result<Vec<u8>, deno_core::anyhow::Error> {
+  let key = key.as_secret_key()?;
+
+  match ctr_length {
+    32 => match key_length {
+      128 => decrypt_aes_ctr_gen::<aes::Aes128, Ctr32BE>(key, counter, data),
+      192 => decrypt_aes_ctr_gen::<aes::Aes192, Ctr32BE>(key, counter, data),
+      256 => decrypt_aes_ctr_gen::<aes::Aes256, Ctr32BE>(key, counter, data),
+      _ => Err(type_error("invalid length")),
+    },
+    64 => match key_length {
+      128 => decrypt_aes_ctr_gen::<aes::Aes128, Ctr64BE>(key, counter, data),
+      192 => decrypt_aes_ctr_gen::<aes::Aes192, Ctr64BE>(key, counter, data),
+      256 => decrypt_aes_ctr_gen::<aes::Aes256, Ctr64BE>(key, counter, data),
+      _ => Err(type_error("invalid length")),
+    },
+    128 => match key_length {
+      128 => decrypt_aes_ctr_gen::<aes::Aes128, Ctr128BE>(key, counter, data),
+      192 => decrypt_aes_ctr_gen::<aes::Aes192, Ctr128BE>(key, counter, data),
+      256 => decrypt_aes_ctr_gen::<aes::Aes256, Ctr128BE>(key, counter, data),
+      _ => Err(type_error("invalid length")),
+    },
+    _ => Err(type_error(
+      "invalid counter length. Currently supported 32/64/128 bits",
+    )),
+  }
+}