upload android base code part6

android/system/keymaster/iso18033kdf.cpp

@@ -0,0 +1,83 @@
+/*
+ * Copyright 2015 The Android Open Source Project
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *      http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+#include "iso18033kdf.h"
+#include "openssl_utils.h"
+
+#include <openssl/evp.h>
+
+namespace keymaster {
+
+inline size_t min(size_t a, size_t b) {
+    return (a < b) ? a : b;
+}
+
+bool Iso18033Kdf::GenerateKey(const uint8_t* info, size_t info_len, uint8_t* output,
+                              size_t output_len) {
+    if (!is_initialized_ || output == nullptr)
+        return false;
+
+    /* Check whether output length is too long as specified in ISO/IEC 18033-2. */
+    if ((0xFFFFFFFFULL + start_counter_) * digest_size_ < (uint64_t)output_len)
+        return false;
+
+    EVP_MD_CTX ctx;
+    EvpMdCtxCleaner ctxCleaner(&ctx);
+    EVP_MD_CTX_init(&ctx);
+
+    size_t num_blocks = (output_len + digest_size_ - 1) / digest_size_;
+    UniquePtr<uint8_t[]> counter(new uint8_t[4]);
+    UniquePtr<uint8_t[]> digest_result(new uint8_t[digest_size_]);
+    if (counter.get() == nullptr || digest_result.get() == nullptr)
+        return false;
+    for (size_t block = 0; block < num_blocks; block++) {
+        switch (digest_type_) {
+        case KM_DIGEST_SHA1:
+            if (!EVP_DigestInit_ex(&ctx, EVP_sha1(), nullptr /* default digest */))
+                return false;
+            break;
+        case KM_DIGEST_SHA_2_256:
+            if (!EVP_DigestInit_ex(&ctx, EVP_sha256(), nullptr /* default digest */))
+                return false;
+            break;
+        default:
+            return false;
+        }
+
+        if (!EVP_DigestUpdate(&ctx, secret_key_.get(), secret_key_len_) ||
+            !Uint32ToBigEndianByteArray(block + start_counter_, counter.get()) ||
+            !EVP_DigestUpdate(&ctx, counter.get(), 4))
+            return false;
+
+        if (info != nullptr && info_len > 0) {
+            if (!EVP_DigestUpdate(&ctx, info, info_len))
+                return false;
+        }
+
+        /* OpenSSL does not accept size_t parameter. */
+        uint32_t uint32_digest_size_ = digest_size_;
+        if (!EVP_DigestFinal_ex(&ctx, digest_result.get(), &uint32_digest_size_) ||
+            uint32_digest_size_ != digest_size_)
+            return false;
+
+        size_t block_start = digest_size_ * block;
+        size_t block_length = min(digest_size_, output_len - block_start);
+        memcpy(output + block_start, digest_result.get(), block_length);
+    }
+    return true;
+}
+
+}  // namespace keymaster