Add Identity Credential HAL, default implementation, and VTS tests.

IIdentityCredentialStore provides an interface to a secure store for
user identity documents.  This HAL is deliberately fairly general and
abstract.  To the extent possible, specification of the message
formats and semantics of communication with credential verification
devices and issuing authorities (IAs) is out of scope for this HAL.

It provides the interface with secure storage but a
credential-specific Android application will be required to implement
the presentation and verification protocols and processes appropriate
for the specific credential type.

Bug: 111446262
Test: VtsHalIdentityCredentialTargetTest
Test: android.hardware.identity-support-lib-test
Test: CtsIdentityTestCases
Change-Id: I64eb50114d645dd475012ad1b889d2177aaf1d37

1 files changed, 351 insertions, 0 deletions

diff --git a/identity/support/src/cppbor_parse.cpp b/identity/support/src/cppbor_parse.cpp
new file mode 100644
index 0000000000..c9ebb8ac1a
--- /dev/null
+++ b/identity/support/src/cppbor_parse.cpp
@@ -0,0 +1,351 @@
+/*
+ * Copyright (c) 2019, 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 "cppbor_parse.h"
+
+#include <sstream>
+#include <stack>
+
+#define LOG_TAG "CppBor"
+#include <android-base/logging.h>
+
+namespace cppbor {
+
+namespace {
+
+std::string insufficientLengthString(size_t bytesNeeded, size_t bytesAvail,
+                                     const std::string& type) {
+    std::stringstream errStream;
+    errStream << "Need " << bytesNeeded << " byte(s) for " << type << ", have " << bytesAvail
+              << ".";
+    return errStream.str();
+}
+
+template <typename T, typename = std::enable_if_t<std::is_unsigned_v<T>>>
+std::tuple<bool, uint64_t, const uint8_t*> parseLength(const uint8_t* pos, const uint8_t* end,
+                                                       ParseClient* parseClient) {
+    if (pos + sizeof(T) > end) {
+        parseClient->error(pos - 1, insufficientLengthString(sizeof(T), end - pos, "length field"));
+        return {false, 0, pos};
+    }
+
+    const uint8_t* intEnd = pos + sizeof(T);
+    T result = 0;
+    do {
+        result = static_cast<T>((result << 8) | *pos++);
+    } while (pos < intEnd);
+    return {true, result, pos};
+}
+
+std::tuple<const uint8_t*, ParseClient*> parseRecursively(const uint8_t* begin, const uint8_t* end,
+                                                          ParseClient* parseClient);
+
+std::tuple<const uint8_t*, ParseClient*> handleUint(uint64_t value, const uint8_t* hdrBegin,
+                                                    const uint8_t* hdrEnd,
+                                                    ParseClient* parseClient) {
+    std::unique_ptr<Item> item = std::make_unique<Uint>(value);
+    return {hdrEnd,
+            parseClient->item(item, hdrBegin, hdrEnd /* valueBegin */, hdrEnd /* itemEnd */)};
+}
+
+std::tuple<const uint8_t*, ParseClient*> handleNint(uint64_t value, const uint8_t* hdrBegin,
+                                                    const uint8_t* hdrEnd,
+                                                    ParseClient* parseClient) {
+    if (value > std::numeric_limits<int64_t>::max()) {
+        parseClient->error(hdrBegin, "NINT values that don't fit in int64_t are not supported.");
+        return {hdrBegin, nullptr /* end parsing */};
+    }
+    std::unique_ptr<Item> item = std::make_unique<Nint>(-1 - static_cast<uint64_t>(value));
+    return {hdrEnd,
+            parseClient->item(item, hdrBegin, hdrEnd /* valueBegin */, hdrEnd /* itemEnd */)};
+}
+
+std::tuple<const uint8_t*, ParseClient*> handleBool(uint64_t value, const uint8_t* hdrBegin,
+                                                    const uint8_t* hdrEnd,
+                                                    ParseClient* parseClient) {
+    std::unique_ptr<Item> item = std::make_unique<Bool>(value == TRUE);
+    return {hdrEnd,
+            parseClient->item(item, hdrBegin, hdrEnd /* valueBegin */, hdrEnd /* itemEnd */)};
+}
+
+std::tuple<const uint8_t*, ParseClient*> handleNull(const uint8_t* hdrBegin, const uint8_t* hdrEnd,
+                                                    ParseClient* parseClient) {
+    std::unique_ptr<Item> item = std::make_unique<Null>();
+    return {hdrEnd,
+            parseClient->item(item, hdrBegin, hdrEnd /* valueBegin */, hdrEnd /* itemEnd */)};
+}
+
+template <typename T>
+std::tuple<const uint8_t*, ParseClient*> handleString(uint64_t length, const uint8_t* hdrBegin,
+                                                      const uint8_t* valueBegin, const uint8_t* end,
+                                                      const std::string& errLabel,
+                                                      ParseClient* parseClient) {
+    if (end - valueBegin < static_cast<ssize_t>(length)) {
+        parseClient->error(hdrBegin, insufficientLengthString(length, end - valueBegin, errLabel));
+        return {hdrBegin, nullptr /* end parsing */};
+    }
+
+    std::unique_ptr<Item> item = std::make_unique<T>(valueBegin, valueBegin + length);
+    return {valueBegin + length,
+            parseClient->item(item, hdrBegin, valueBegin, valueBegin + length)};
+}
+
+class IncompleteItem {
+  public:
+    virtual ~IncompleteItem() {}
+    virtual void add(std::unique_ptr<Item> item) = 0;
+};
+
+class IncompleteArray : public Array, public IncompleteItem {
+  public:
+    IncompleteArray(size_t size) : mSize(size) {}
+
+    // We return the "complete" size, rather than the actual size.
+    size_t size() const override { return mSize; }
+
+    void add(std::unique_ptr<Item> item) override {
+        mEntries.reserve(mSize);
+        mEntries.push_back(std::move(item));
+    }
+
+  private:
+    size_t mSize;
+};
+
+class IncompleteMap : public Map, public IncompleteItem {
+  public:
+    IncompleteMap(size_t size) : mSize(size) {}
+
+    // We return the "complete" size, rather than the actual size.
+    size_t size() const override { return mSize; }
+
+    void add(std::unique_ptr<Item> item) override {
+        mEntries.reserve(mSize * 2);
+        mEntries.push_back(std::move(item));
+    }
+
+  private:
+    size_t mSize;
+};
+
+class IncompleteSemantic : public Semantic, public IncompleteItem {
+  public:
+    IncompleteSemantic(uint64_t value) : Semantic(value) {}
+
+    // We return the "complete" size, rather than the actual size.
+    size_t size() const override { return 1; }
+
+    void add(std::unique_ptr<Item> item) override {
+        mEntries.reserve(1);
+        mEntries.push_back(std::move(item));
+    }
+};
+
+std::tuple<const uint8_t*, ParseClient*> handleEntries(size_t entryCount, const uint8_t* hdrBegin,
+                                                       const uint8_t* pos, const uint8_t* end,
+                                                       const std::string& typeName,
+                                                       ParseClient* parseClient) {
+    while (entryCount > 0) {
+        --entryCount;
+        if (pos == end) {
+            parseClient->error(hdrBegin, "Not enough entries for " + typeName + ".");
+            return {hdrBegin, nullptr /* end parsing */};
+        }
+        std::tie(pos, parseClient) = parseRecursively(pos, end, parseClient);
+        if (!parseClient) return {hdrBegin, nullptr};
+    }
+    return {pos, parseClient};
+}
+
+std::tuple<const uint8_t*, ParseClient*> handleCompound(
+        std::unique_ptr<Item> item, uint64_t entryCount, const uint8_t* hdrBegin,
+        const uint8_t* valueBegin, const uint8_t* end, const std::string& typeName,
+        ParseClient* parseClient) {
+    parseClient =
+            parseClient->item(item, hdrBegin, valueBegin, valueBegin /* don't know the end yet */);
+    if (!parseClient) return {hdrBegin, nullptr};
+
+    const uint8_t* pos;
+    std::tie(pos, parseClient) =
+            handleEntries(entryCount, hdrBegin, valueBegin, end, typeName, parseClient);
+    if (!parseClient) return {hdrBegin, nullptr};
+
+    return {pos, parseClient->itemEnd(item, hdrBegin, valueBegin, pos)};
+}
+
+std::tuple<const uint8_t*, ParseClient*> parseRecursively(const uint8_t* begin, const uint8_t* end,
+                                                          ParseClient* parseClient) {
+    const uint8_t* pos = begin;
+
+    MajorType type = static_cast<MajorType>(*pos & 0xE0);
+    uint8_t tagInt = *pos & 0x1F;
+    ++pos;
+
+    bool success = true;
+    uint64_t addlData;
+    if (tagInt < ONE_BYTE_LENGTH || tagInt > EIGHT_BYTE_LENGTH) {
+        addlData = tagInt;
+    } else {
+        switch (tagInt) {
+            case ONE_BYTE_LENGTH:
+                std::tie(success, addlData, pos) = parseLength<uint8_t>(pos, end, parseClient);
+                break;
+
+            case TWO_BYTE_LENGTH:
+                std::tie(success, addlData, pos) = parseLength<uint16_t>(pos, end, parseClient);
+                break;
+
+            case FOUR_BYTE_LENGTH:
+                std::tie(success, addlData, pos) = parseLength<uint32_t>(pos, end, parseClient);
+                break;
+
+            case EIGHT_BYTE_LENGTH:
+                std::tie(success, addlData, pos) = parseLength<uint64_t>(pos, end, parseClient);
+                break;
+
+            default:
+                CHECK(false);  //  It's impossible to get here
+                break;
+        }
+    }
+
+    if (!success) return {begin, nullptr};
+
+    switch (type) {
+        case UINT:
+            return handleUint(addlData, begin, pos, parseClient);
+
+        case NINT:
+            return handleNint(addlData, begin, pos, parseClient);
+
+        case BSTR:
+            return handleString<Bstr>(addlData, begin, pos, end, "byte string", parseClient);
+
+        case TSTR:
+            return handleString<Tstr>(addlData, begin, pos, end, "text string", parseClient);
+
+        case ARRAY:
+            return handleCompound(std::make_unique<IncompleteArray>(addlData), addlData, begin, pos,
+                                  end, "array", parseClient);
+
+        case MAP:
+            return handleCompound(std::make_unique<IncompleteMap>(addlData), addlData * 2, begin,
+                                  pos, end, "map", parseClient);
+
+        case SEMANTIC:
+            return handleCompound(std::make_unique<IncompleteSemantic>(addlData), 1, begin, pos,
+                                  end, "semantic", parseClient);
+
+        case SIMPLE:
+            switch (addlData) {
+                case TRUE:
+                case FALSE:
+                    return handleBool(addlData, begin, pos, parseClient);
+                case NULL_V:
+                    return handleNull(begin, pos, parseClient);
+            }
+    }
+    CHECK(false);  // Impossible to get here.
+    return {};
+}
+
+class FullParseClient : public ParseClient {
+  public:
+    virtual ParseClient* item(std::unique_ptr<Item>& item, const uint8_t*, const uint8_t*,
+                              const uint8_t* end) override {
+        if (mParentStack.empty() && !item->isCompound()) {
+            // This is the first and only item.
+            mTheItem = std::move(item);
+            mPosition = end;
+            return nullptr;  //  We're done.
+        }
+
+        if (item->isCompound()) {
+            // Starting a new compound data item, i.e. a new parent.  Save it on the parent stack.
+            // It's safe to save a raw pointer because the unique_ptr is guaranteed to stay in
+            // existence until the corresponding itemEnd() call.
+            assert(dynamic_cast<CompoundItem*>(item.get()));
+            mParentStack.push(static_cast<CompoundItem*>(item.get()));
+            return this;
+        } else {
+            appendToLastParent(std::move(item));
+            return this;
+        }
+    }
+
+    virtual ParseClient* itemEnd(std::unique_ptr<Item>& item, const uint8_t*, const uint8_t*,
+                                 const uint8_t* end) override {
+        CHECK(item->isCompound() && item.get() == mParentStack.top());
+        mParentStack.pop();
+
+        if (mParentStack.empty()) {
+            mTheItem = std::move(item);
+            mPosition = end;
+            return nullptr;  // We're done
+        } else {
+            appendToLastParent(std::move(item));
+            return this;
+        }
+    }
+
+    virtual void error(const uint8_t* position, const std::string& errorMessage) override {
+        mPosition = position;
+        mErrorMessage = errorMessage;
+    }
+
+    std::tuple<std::unique_ptr<Item> /* result */, const uint8_t* /* newPos */,
+               std::string /* errMsg */>
+    parseResult() {
+        std::unique_ptr<Item> p = std::move(mTheItem);
+        return {std::move(p), mPosition, std::move(mErrorMessage)};
+    }
+
+  private:
+    void appendToLastParent(std::unique_ptr<Item> item) {
+        auto parent = mParentStack.top();
+        assert(dynamic_cast<IncompleteItem*>(parent));
+        if (parent->type() == ARRAY) {
+            static_cast<IncompleteArray*>(parent)->add(std::move(item));
+        } else if (parent->type() == MAP) {
+            static_cast<IncompleteMap*>(parent)->add(std::move(item));
+        } else if (parent->type() == SEMANTIC) {
+            static_cast<IncompleteSemantic*>(parent)->add(std::move(item));
+        } else {
+            CHECK(false);  // Impossible to get here.
+        }
+    }
+
+    std::unique_ptr<Item> mTheItem;
+    std::stack<CompoundItem*> mParentStack;
+    const uint8_t* mPosition = nullptr;
+    std::string mErrorMessage;
+};
+
+}  // anonymous namespace
+
+void parse(const uint8_t* begin, const uint8_t* end, ParseClient* parseClient) {
+    parseRecursively(begin, end, parseClient);
+}
+
+std::tuple<std::unique_ptr<Item> /* result */, const uint8_t* /* newPos */,
+           std::string /* errMsg */>
+parse(const uint8_t* begin, const uint8_t* end) {
+    FullParseClient parseClient;
+    parse(begin, end, &parseClient);
+    return parseClient.parseResult();
+}
+
+}  // namespace cppbor