crypto: allocate more memory for cipher.update()

For key wrapping algorithms, calling EVP_CipherUpdate() with null output could obtain the size for the ciphertext. Then use the returned size to allocate output buffer. Also add a test case to verify des3-wrap. Signed-off-by: Yihong Wang <yh.wang@ibm.com> PR-URL: #20370 Fixes: #19655 Reviewed-By: Tobias Nießen <tniessen@tnie.de> Reviewed-By: Ben Noordhuis <info@bnoordhuis.nl> Reviewed-By: James M Snell <jasnell@gmail.com>

Author: yhwang

src/node_crypto.cc

@@ -2987,14 +2987,28 @@ CipherBase::UpdateResult CipherBase::Update(const char* data,
  auth_tag_set_ = true;
  }
 
- *out_len = len + EVP_CIPHER_CTX_block_size(ctx_);
- *out = Malloc<unsigned char>(static_cast<size_t>(*out_len));
+ *out_len = 0;
+ int buff_len = len + EVP_CIPHER_CTX_block_size(ctx_);
+ // For key wrapping algorithms, get output size by calling
+ // EVP_CipherUpdate() with null output.
+ if (mode == EVP_CIPH_WRAP_MODE &&
+ EVP_CipherUpdate(ctx_,
+ nullptr,
+ &buff_len,
+ reinterpret_cast<const unsigned char*>(data),
+ len) != 1) {
+ return kErrorState;
+ }
+
+ *out = Malloc<unsigned char>(buff_len);
  int r = EVP_CipherUpdate(ctx_,
  *out,
  out_len,
  reinterpret_cast<const unsigned char*>(data),
  len);
 
+ CHECK_LE(*out_len, buff_len);
+
  // When in CCM mode, EVP_CipherUpdate will fail if the authentication tag is
  // invalid. In that case, remember the error and throw in final().
  if (!r && kind_ == kDecipher && mode == EVP_CIPH_CCM_MODE) {

test/parallel/test-crypto-des3-wrap.js

@@ -0,0 +1,25 @@
+'use strict';
+const common = require('../common');
+if (!common.hasCrypto)
+ common.skip('missing crypto');
+
+const assert = require('assert');
+const crypto = require('crypto');
+
+// Test case for des-ede3 wrap/unwrap. des3-wrap needs extra 2x blocksize
+// then plaintext to store ciphertext.
+const test = {
+ key: Buffer.from('3c08e25be22352910671cfe4ba3652b1220a8a7769b490ba', 'hex'),
+ iv: Buffer.alloc(0),
+ plaintext: '32|RmVZZkFUVmpRRkp0TmJaUm56ZU9qcnJkaXNNWVNpTTU*|iXmckfRWZBG' +
+ 'WWELweCBsThSsfUHLeRe0KCsK8ooHgxie0zOINpXxfZi/oNG7uq9JWFVCk70gfzQH8ZU' +
+ 'JjAfaFg**'
+};
+
+const cipher = crypto.createCipheriv('des3-wrap', test.key, test.iv);
+const ciphertext = cipher.update(test.plaintext, 'utf8');
+
+const decipher = crypto.createDecipheriv('des3-wrap', test.key, test.iv);
+const msg = decipher.update(ciphertext, 'buffer', 'utf8');
+
+assert.strictEqual(msg, test.plaintext);