Don't sign extensions with an unsupported/invalid private key

BUG=125997
TEST=manually test with unsupported/invalid key


Review URL: http://codereview.chromium.org/10370002

git-svn-id: svn://svn.chromium.org/chrome/trunk/src@135292 0039d316-1c4b-4281-b951-d872f2087c98

crypto/rsa_private_key_win.cc

@@ -45,17 +45,18 @@ RSAPrivateKey* RSAPrivateKey::CreateFromPrivateKeyInfo(
     return NULL;
 
   PrivateKeyInfoCodec pki(false);  // Little-Endian
-  pki.Import(input);
-
-  int blob_size = sizeof(PUBLICKEYSTRUC) +
-                  sizeof(RSAPUBKEY) +
-                  pki.modulus()->size() +
-                  pki.prime1()->size() +
-                  pki.prime2()->size() +
-                  pki.exponent1()->size() +
-                  pki.exponent2()->size() +
-                  pki.coefficient()->size() +
-                  pki.private_exponent()->size();
+  if (!pki.Import(input))
+    return NULL;
+
+  size_t blob_size = sizeof(PUBLICKEYSTRUC) +
+                     sizeof(RSAPUBKEY) +
+                     pki.modulus()->size() +
+                     pki.prime1()->size() +
+                     pki.prime2()->size() +
+                     pki.exponent1()->size() +
+                     pki.exponent2()->size() +
+                     pki.coefficient()->size() +
+                     pki.private_exponent()->size();
   scoped_array<BYTE> blob(new BYTE[blob_size]);
 
   uint8* dest = blob.get();
@@ -98,9 +99,11 @@ RSAPrivateKey* RSAPrivateKey::CreateFromPrivateKeyInfo(
     return NULL;
   }
   if (!CryptImportKey(result->provider_,
-                      reinterpret_cast<uint8*>(public_key_struc), blob_size, 0,
-                      CRYPT_EXPORTABLE, result->key_.receive()))
+                      reinterpret_cast<uint8*>(public_key_struc),
+                      static_cast<DWORD>(blob_size), 0, CRYPT_EXPORTABLE,
+                      result->key_.receive())) {
     return NULL;
+  }
 
   return result.release();
 }