Refactor keystore.
This CL isn't nearly as big as it looks. It doesn't change keystore
functionality, it just moves all of the classes out of the former
keystore.cpp into their own .h and .cpp files.
Note that this is a cherry-pick from:
https://android-review.googlesource.com/#/c/194971
Change-Id: Ide326c4f1d03984994d1bd9a76fa68d37da230dc
diff --git a/keystore/blob.cpp b/keystore/blob.cpp
new file mode 100644
index 0000000..8b08f07
--- /dev/null
+++ b/keystore/blob.cpp
@@ -0,0 +1,213 @@
+/*
+ * Copyright (C) 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.
+ */
+
+#define LOG_TAG "keystore"
+
+#include <arpa/inet.h>
+#include <errno.h>
+#include <fcntl.h>
+#include <string.h>
+
+#include <cutils/log.h>
+
+#include "blob.h"
+#include "entropy.h"
+
+#include "keystore_utils.h"
+
+Blob::Blob(const uint8_t* value, size_t valueLength, const uint8_t* info, uint8_t infoLength,
+ BlobType type) {
+ memset(&mBlob, 0, sizeof(mBlob));
+ if (valueLength > VALUE_SIZE) {
+ valueLength = VALUE_SIZE;
+ ALOGW("Provided blob length too large");
+ }
+ if (infoLength + valueLength > VALUE_SIZE) {
+ infoLength = VALUE_SIZE - valueLength;
+ ALOGW("Provided info length too large");
+ }
+ mBlob.length = valueLength;
+ memcpy(mBlob.value, value, valueLength);
+
+ mBlob.info = infoLength;
+ memcpy(mBlob.value + valueLength, info, infoLength);
+
+ mBlob.version = CURRENT_BLOB_VERSION;
+ mBlob.type = uint8_t(type);
+
+ if (type == TYPE_MASTER_KEY) {
+ mBlob.flags = KEYSTORE_FLAG_ENCRYPTED;
+ } else {
+ mBlob.flags = KEYSTORE_FLAG_NONE;
+ }
+}
+
+Blob::Blob(blob b) {
+ mBlob = b;
+}
+
+Blob::Blob() {
+ memset(&mBlob, 0, sizeof(mBlob));
+}
+
+bool Blob::isEncrypted() const {
+ if (mBlob.version < 2) {
+ return true;
+ }
+
+ return mBlob.flags & KEYSTORE_FLAG_ENCRYPTED;
+}
+
+void Blob::setEncrypted(bool encrypted) {
+ if (encrypted) {
+ mBlob.flags |= KEYSTORE_FLAG_ENCRYPTED;
+ } else {
+ mBlob.flags &= ~KEYSTORE_FLAG_ENCRYPTED;
+ }
+}
+
+void Blob::setFallback(bool fallback) {
+ if (fallback) {
+ mBlob.flags |= KEYSTORE_FLAG_FALLBACK;
+ } else {
+ mBlob.flags &= ~KEYSTORE_FLAG_FALLBACK;
+ }
+}
+
+ResponseCode Blob::writeBlob(const char* filename, AES_KEY* aes_key, State state,
+ Entropy* entropy) {
+ ALOGV("writing blob %s", filename);
+ if (isEncrypted()) {
+ if (state != STATE_NO_ERROR) {
+ ALOGD("couldn't insert encrypted blob while not unlocked");
+ return LOCKED;
+ }
+
+ if (!entropy->generate_random_data(mBlob.vector, AES_BLOCK_SIZE)) {
+ ALOGW("Could not read random data for: %s", filename);
+ return SYSTEM_ERROR;
+ }
+ }
+
+ // data includes the value and the value's length
+ size_t dataLength = mBlob.length + sizeof(mBlob.length);
+ // pad data to the AES_BLOCK_SIZE
+ size_t digestedLength = ((dataLength + AES_BLOCK_SIZE - 1) / AES_BLOCK_SIZE * AES_BLOCK_SIZE);
+ // encrypted data includes the digest value
+ size_t encryptedLength = digestedLength + MD5_DIGEST_LENGTH;
+ // move info after space for padding
+ memmove(&mBlob.encrypted[encryptedLength], &mBlob.value[mBlob.length], mBlob.info);
+ // zero padding area
+ memset(mBlob.value + mBlob.length, 0, digestedLength - dataLength);
+
+ mBlob.length = htonl(mBlob.length);
+
+ if (isEncrypted()) {
+ MD5(mBlob.digested, digestedLength, mBlob.digest);
+
+ uint8_t vector[AES_BLOCK_SIZE];
+ memcpy(vector, mBlob.vector, AES_BLOCK_SIZE);
+ AES_cbc_encrypt(mBlob.encrypted, mBlob.encrypted, encryptedLength, aes_key, vector,
+ AES_ENCRYPT);
+ }
+
+ size_t headerLength = (mBlob.encrypted - (uint8_t*)&mBlob);
+ size_t fileLength = encryptedLength + headerLength + mBlob.info;
+
+ const char* tmpFileName = ".tmp";
+ int out =
+ TEMP_FAILURE_RETRY(open(tmpFileName, O_WRONLY | O_TRUNC | O_CREAT, S_IRUSR | S_IWUSR));
+ if (out < 0) {
+ ALOGW("could not open file: %s: %s", tmpFileName, strerror(errno));
+ return SYSTEM_ERROR;
+ }
+ size_t writtenBytes = writeFully(out, (uint8_t*)&mBlob, fileLength);
+ if (close(out) != 0) {
+ return SYSTEM_ERROR;
+ }
+ if (writtenBytes != fileLength) {
+ ALOGW("blob not fully written %zu != %zu", writtenBytes, fileLength);
+ unlink(tmpFileName);
+ return SYSTEM_ERROR;
+ }
+ if (rename(tmpFileName, filename) == -1) {
+ ALOGW("could not rename blob to %s: %s", filename, strerror(errno));
+ return SYSTEM_ERROR;
+ }
+ return NO_ERROR;
+}
+
+ResponseCode Blob::readBlob(const char* filename, AES_KEY* aes_key, State state) {
+ ALOGV("reading blob %s", filename);
+ int in = TEMP_FAILURE_RETRY(open(filename, O_RDONLY));
+ if (in < 0) {
+ return (errno == ENOENT) ? KEY_NOT_FOUND : SYSTEM_ERROR;
+ }
+ // fileLength may be less than sizeof(mBlob) since the in
+ // memory version has extra padding to tolerate rounding up to
+ // the AES_BLOCK_SIZE
+ size_t fileLength = readFully(in, (uint8_t*)&mBlob, sizeof(mBlob));
+ if (close(in) != 0) {
+ return SYSTEM_ERROR;
+ }
+
+ if (fileLength == 0) {
+ return VALUE_CORRUPTED;
+ }
+
+ if (isEncrypted() && (state != STATE_NO_ERROR)) {
+ return LOCKED;
+ }
+
+ size_t headerLength = (mBlob.encrypted - (uint8_t*)&mBlob);
+ if (fileLength < headerLength) {
+ return VALUE_CORRUPTED;
+ }
+
+ ssize_t encryptedLength = fileLength - (headerLength + mBlob.info);
+ if (encryptedLength < 0) {
+ return VALUE_CORRUPTED;
+ }
+
+ ssize_t digestedLength;
+ if (isEncrypted()) {
+ if (encryptedLength % AES_BLOCK_SIZE != 0) {
+ return VALUE_CORRUPTED;
+ }
+
+ AES_cbc_encrypt(mBlob.encrypted, mBlob.encrypted, encryptedLength, aes_key, mBlob.vector,
+ AES_DECRYPT);
+ digestedLength = encryptedLength - MD5_DIGEST_LENGTH;
+ uint8_t computedDigest[MD5_DIGEST_LENGTH];
+ MD5(mBlob.digested, digestedLength, computedDigest);
+ if (memcmp(mBlob.digest, computedDigest, MD5_DIGEST_LENGTH) != 0) {
+ return VALUE_CORRUPTED;
+ }
+ } else {
+ digestedLength = encryptedLength;
+ }
+
+ ssize_t maxValueLength = digestedLength - sizeof(mBlob.length);
+ mBlob.length = ntohl(mBlob.length);
+ if (mBlob.length < 0 || mBlob.length > maxValueLength) {
+ return VALUE_CORRUPTED;
+ }
+ if (mBlob.info != 0) {
+ // move info from after padding to after data
+ memmove(&mBlob.value[mBlob.length], &mBlob.value[maxValueLength], mBlob.info);
+ }
+ return ::NO_ERROR;
+}