crypto: Allow GCM ciphers to have a longer IV length

GCM cipher IV length can be >=1 bytes. When not the default 12 bytes (96 bits) sets the IV length using `EVP_CIPHER_CTX_ctrl` with type `EVP_CTRL_GCM_SET_IVLEN` PR-URL: nodejs#6376 Reviewed-By: Ben Noordhuis <[email protected]> Reviewed-By: Fedor Indutny <[email protected]> Reviewed-By: James M Snell <[email protected]> Reviewed-By: Shigeki Ohtsu <[email protected]>
sam-github · Jun 27, 2016 · 2996b5c · 2996b5c
1 parent 2787d70
commit 2996b5c
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Showing 2 changed files with 315 additions and 24 deletions.
diff --git a/src/node_crypto.cc b/src/node_crypto.cc
@@ -3271,12 +3271,24 @@ void CipherBase::InitIv(const char* cipher_type,
   /* OpenSSL versions up to 0.9.8l failed to return the correct
      iv_length (0) for ECB ciphers */
   if (EVP_CIPHER_iv_length(cipher_) != iv_len &&
-      !(EVP_CIPHER_mode(cipher_) == EVP_CIPH_ECB_MODE && iv_len == 0)) {
+      !(EVP_CIPHER_mode(cipher_) == EVP_CIPH_ECB_MODE && iv_len == 0) &&
+      !(EVP_CIPHER_mode(cipher_) == EVP_CIPH_GCM_MODE) && iv_len > 0) {
     return env()->ThrowError("Invalid IV length");
   }
+
   EVP_CIPHER_CTX_init(&ctx_);
   const bool encrypt = (kind_ == kCipher);
   EVP_CipherInit_ex(&ctx_, cipher_, nullptr, nullptr, nullptr, encrypt);
+
+  /* Set IV length. Only required if GCM cipher and IV is not default iv. */
+  if (EVP_CIPHER_mode(cipher_) == EVP_CIPH_GCM_MODE &&
+      iv_len != EVP_CIPHER_iv_length(cipher_)) {
+    if (!EVP_CIPHER_CTX_ctrl(&ctx_, EVP_CTRL_GCM_SET_IVLEN, iv_len, nullptr)) {
+      EVP_CIPHER_CTX_cleanup(&ctx_);
+      return env()->ThrowError("Invalid IV length");
+    }
+  }
+
   if (!EVP_CIPHER_CTX_set_key_length(&ctx_, key_len)) {
     EVP_CIPHER_CTX_cleanup(&ctx_);
     return env()->ThrowError("Invalid key length");