common: ocispec: return integrity error on file read

src/common/ocispec/imageconfig.cpp

@@ -4,9 +4,6 @@
  * SPDX-License-Identifier: Apache-2.0
  */
 
-#include <fstream>
-#include <sstream>
-
 #include <common/utils/exception.hpp>
 #include <common/utils/json.hpp>
 #include <common/utils/time.hpp>
@@ -118,14 +115,8 @@ Poco::JSON::Object RootfsToJSON(const aos::oci::Rootfs& rootfs)
 Error OCISpec::LoadImageConfig(const String& path, aos::oci::ImageConfig& imageConfig)
 {
     try {
-        std::ifstream file(path.CStr());
-
-        if (!file.is_open()) {
-            AOS_ERROR_THROW(ErrorEnum::eNotFound, "failed to open file");
-        }
-
-        auto [var, err] = utils::ParseJson(file);
-        AOS_ERROR_CHECK_AND_THROW(err, "failed to parse json");
+        auto [var, err] = utils::ReadJsonFromFile(path.CStr());
+        AOS_ERROR_CHECK_AND_THROW(err, "failed to load json file");
 
         Poco::JSON::Object::Ptr             object = var.extract<Poco::JSON::Object::Ptr>();
         utils::CaseInsensitiveObjectWrapper wrapper(object);

src/common/ocispec/imageindex.cpp

@@ -4,9 +4,6 @@
  * SPDX-License-Identifier: Apache-2.0
  */
 
-#include <fstream>
-#include <sstream>
-
 #include <common/utils/exception.hpp>
 #include <common/utils/json.hpp>
 #include <common/utils/time.hpp>
@@ -56,14 +53,8 @@ Poco::JSON::Object IndexContentDescriptorToJSONObject(const aos::oci::IndexConte
 Error OCISpec::LoadImageIndex(const String& path, aos::oci::ImageIndex& index)
 {
     try {
-        std::ifstream file(path.CStr());
-
-        if (!file.is_open()) {
-            AOS_ERROR_THROW(ErrorEnum::eNotFound, "failed to open file");
-        }
-
-        auto [var, err] = utils::ParseJson(file);
-        AOS_ERROR_CHECK_AND_THROW(err, "failed to parse json");
+        auto [var, err] = utils::ReadJsonFromFile(path.CStr());
+        AOS_ERROR_CHECK_AND_THROW(err, "failed to load json file");
 
         Poco::JSON::Object::Ptr             object = var.extract<Poco::JSON::Object::Ptr>();
         utils::CaseInsensitiveObjectWrapper wrapper(object);

src/common/ocispec/imagemanifest.cpp

@@ -4,9 +4,6 @@
  * SPDX-License-Identifier: Apache-2.0
  */
 
-#include <fstream>
-#include <sstream>
-
 #include <common/utils/exception.hpp>
 #include <common/utils/json.hpp>
 #include <common/utils/time.hpp>
@@ -23,14 +20,8 @@ namespace aos::common::oci {
 Error OCISpec::LoadImageManifest(const String& path, aos::oci::ImageManifest& manifest)
 {
     try {
-        std::ifstream file(path.CStr());
-
-        if (!file.is_open()) {
-            AOS_ERROR_THROW(ErrorEnum::eNotFound, "failed to open file");
-        }
-
-        auto [var, err] = utils::ParseJson(file);
-        AOS_ERROR_CHECK_AND_THROW(err, "failed to parse json");
+        auto [var, err] = utils::ReadJsonFromFile(path.CStr());
+        AOS_ERROR_CHECK_AND_THROW(err, "failed to load json file");
 
         Poco::JSON::Object::Ptr             object = var.extract<Poco::JSON::Object::Ptr>();
         utils::CaseInsensitiveObjectWrapper wrapper(object);

src/common/ocispec/itemconfig.cpp

@@ -4,9 +4,6 @@
  * SPDX-License-Identifier: Apache-2.0
  */
 
-#include <fstream>
-#include <sstream>
-
 #include <common/utils/exception.hpp>
 #include <common/utils/json.hpp>
 #include <common/utils/time.hpp>
@@ -458,14 +455,8 @@ Poco::JSON::Object AlertRulesToJSON(const AlertRules& rules)
 Error OCISpec::LoadItemConfig(const String& path, aos::oci::ItemConfig& itemConfig)
 {
     try {
-        std::ifstream file(path.CStr());
-
-        if (!file.is_open()) {
-            AOS_ERROR_THROW(ErrorEnum::eNotFound, "failed to open file");
-        }
-
-        auto [var, err] = utils::ParseJson(file);
-        AOS_ERROR_CHECK_AND_THROW(err, "failed to parse json");
+        auto [var, err] = utils::ReadJsonFromFile(path.CStr());
+        AOS_ERROR_CHECK_AND_THROW(err, "failed to load json file");
 
         Poco::JSON::Object::Ptr             object = var.extract<Poco::JSON::Object::Ptr>();
         utils::CaseInsensitiveObjectWrapper wrapper(object);

src/common/ocispec/runtimeconfig.cpp

@@ -4,8 +4,6 @@
  * SPDX-License-Identifier: Apache-2.0
  */
 
-#include <fstream>
-
 #include <common/utils/exception.hpp>
 #include <common/utils/json.hpp>
 #include <common/utils/time.hpp>
@@ -928,14 +926,8 @@ Poco::JSON::Object VMToJSON(const aos::oci::VM& vm)
 Error OCISpec::LoadRuntimeConfig(const String& path, aos::oci::RuntimeConfig& runtimeConfig)
 {
     try {
-        std::ifstream file(path.CStr());
-
-        if (!file.is_open()) {
-            AOS_ERROR_THROW(ErrorEnum::eNotFound, "failed to open file");
-        }
-
-        auto [var, err] = utils::ParseJson(file);
-        AOS_ERROR_CHECK_AND_THROW(err, "failed to parse json");
+        auto [var, err] = utils::ReadJsonFromFile(path.CStr());
+        AOS_ERROR_CHECK_AND_THROW(err, "failed to load json file");
 
         Poco::JSON::Object::Ptr             object = var.extract<Poco::JSON::Object::Ptr>();
         utils::CaseInsensitiveObjectWrapper wrapper(object);

src/common/ocispec/tests/ocispec.cpp

@@ -4,6 +4,15 @@
  * SPDX-License-Identifier: Apache-2.0
  */
 
+#include <sys/syscall.h>
+#include <unistd.h>
+
+#include <atomic>
+#include <cerrno>
+#include <functional>
+#include <memory>
+#include <vector>
+
 #include <Poco/JSON/Object.h>
 #include <gtest/gtest.h>
 
@@ -16,6 +25,25 @@
 
 using namespace testing;
 
+namespace {
+
+std::atomic<int> sReadErrno {0};
+
+} // namespace
+
+// File read is intercepted to inject the read errors of the integrity checked storage, which can't be reproduced with a
+// regular file.
+extern "C" ssize_t read(int fd, void* buf, size_t count)
+{
+    if (const auto readErrno = sReadErrno.load(); readErrno != 0) {
+        errno = readErrno;
+
+        return -1;
+    }
+
+    return static_cast<ssize_t>(syscall(SYS_read, fd, buf, count));
+}
+
 namespace aos::common::jsonprovider {
 
 namespace {
@@ -318,6 +346,29 @@ std::string MakeItemConfigWithPermissions(const std::string& permissions)
 )";
 }
 
+using LoadFunc = std::function<Error(oci::OCISpec&, const String&)>;
+
+template <typename T, typename Method>
+LoadFunc MakeLoadFunc(Method method)
+{
+    return [method](oci::OCISpec& ociSpec, const String& path) {
+        auto object = std::make_unique<T>();
+
+        return (ociSpec.*method)(path, *object);
+    };
+}
+
+std::vector<LoadFunc> GetLoadFuncs()
+{
+    return {
+        MakeLoadFunc<aos::oci::ImageIndex>(&oci::OCISpec::LoadImageIndex),
+        MakeLoadFunc<aos::oci::ImageManifest>(&oci::OCISpec::LoadImageManifest),
+        MakeLoadFunc<aos::oci::ImageConfig>(&oci::OCISpec::LoadImageConfig),
+        MakeLoadFunc<aos::oci::ItemConfig>(&oci::OCISpec::LoadItemConfig),
+        MakeLoadFunc<aos::oci::RuntimeConfig>(&oci::OCISpec::LoadRuntimeConfig),
+    };
+}
+
 class OCISpecTest : public Test {
 public:
     void SetUp() override
@@ -332,6 +383,8 @@ class OCISpecTest : public Test {
         fs::WriteStringToFile(cItemConfigPath, cItemConfig, S_IRUSR | S_IWUSR);
     }
 
+    void TearDown() override { sReadErrno = 0; }
+
     oci::OCISpec mOCISpec;
 };
 
@@ -582,6 +635,56 @@ TEST_F(OCISpecTest, LoadItemConfigPermissionsExceedLimitsFails)
     }
 }
 
+TEST_F(OCISpecTest, LoadReadErrorIsIntegrity)
+{
+    for (const auto readErrno : {EIO, EBADMSG}) {
+        for (const auto& load : GetLoadFuncs()) {
+            sReadErrno     = readErrno;
+            const auto err = load(mOCISpec, cImageIndexPath);
+            sReadErrno     = 0;
+
+            EXPECT_TRUE(err.Is(ErrorEnum::eIntegrity))
+                << "errno: " << readErrno << ", error: " << tests::utils::ErrorToStr(err);
+        }
+    }
+}
+
+TEST_F(OCISpecTest, LoadOtherReadErrorIsReturnedAsIs)
+{
+    for (const auto& load : GetLoadFuncs()) {
+        sReadErrno     = EPERM;
+        const auto err = load(mOCISpec, cImageIndexPath);
+        sReadErrno     = 0;
+
+        EXPECT_EQ(err.Value(), ErrorEnum::eRuntime) << tests::utils::ErrorToStr(err);
+        EXPECT_EQ(err.Code(), EPERM) << tests::utils::ErrorToStr(err);
+    }
+}
+
+TEST_F(OCISpecTest, LoadMissingFileIsNotFound)
+{
+    const auto cMissingPath = fs::JoinPath(cTestBaseDir, "missing.json");
+
+    for (const auto& load : GetLoadFuncs()) {
+        const auto err = load(mOCISpec, cMissingPath);
+
+        EXPECT_TRUE(err.Is(ErrorEnum::eNotFound)) << tests::utils::ErrorToStr(err);
+    }
+}
+
+TEST_F(OCISpecTest, LoadMalformedFileIsNotIntegrity)
+{
+    const auto cMalformedPath = fs::JoinPath(cTestBaseDir, "malformed.json");
+
+    ASSERT_TRUE(fs::WriteStringToFile(cMalformedPath, "{\"schemaVersion\": ", S_IRUSR | S_IWUSR).IsNone());
+
+    for (const auto& load : GetLoadFuncs()) {
+        const auto err = load(mOCISpec, cMalformedPath);
+
+        EXPECT_TRUE(err.Is(ErrorEnum::eInvalidArgument)) << tests::utils::ErrorToStr(err);
+    }
+}
+
 TEST_F(OCISpecTest, ServiceConfigFromFileRunParams)
 {
     const std::vector<aos::RunParameters> runParams = {

src/common/utils/json.cpp

@@ -6,12 +6,16 @@
  */
 
 #include <algorithm>
+#include <filesystem>
 #include <fstream>
 #include <sstream>
+#include <system_error>
 
 #include <Poco/JSON/JSONException.h>
 #include <Poco/JSON/Parser.h>
 
+#include <core/common/tools/fs.hpp>
+
 #include "exception.hpp"
 #include "json.hpp"
 
@@ -133,6 +137,25 @@ Error WriteJsonToFile(const Poco::JSON::Object::Ptr& json, const std::string& pa
     return ErrorEnum::eNone;
 }
 
+aos::RetWithError<Poco::Dynamic::Var> ReadJsonFromFile(const std::string& path)
+{
+    std::error_code ec;
+
+    const auto size = std::filesystem::file_size(path, ec);
+
+    // The size error is not returned: if the file can't be accessed, ReadFile fails with the proper error.
+    std::string content(ec ? 0 : size, '\0');
+    auto        buffer = Array<uint8_t>(reinterpret_cast<const uint8_t*>(content.data()), content.size());
+
+    if (auto err = fs::ReadFile(path.c_str(), buffer); !err.IsNone()) {
+        return {{}, AOS_ERROR_WRAP(err)};
+    }
+
+    content.resize(buffer.Size());
+
+    return ParseJson(content);
+}
+
 Poco::Dynamic::Var FindByPath(const Poco::Dynamic::Var object, const std::vector<std::string>& keys)
 {
     if (keys.empty()) {

src/common/utils/json.hpp

@@ -55,6 +55,17 @@ aos::RetWithError<Poco::Dynamic::Var> ParseJson(std::istream& in) noexcept;
  */
 Error WriteJsonToFile(const Poco::JSON::Object::Ptr& json, const std::string& path);
 
+/**
+ * Reads and parses json from file.
+ *
+ * The errors of the file open and read are returned as follows: EIO and EBADMSG as ErrorEnum::eIntegrity, ENOENT as
+ * ErrorEnum::eNotFound, any other errno as is.
+ *
+ * @param path path to the file.
+ * @return aos::RetWithError<Poco::Dynamic::Var>.
+ */
+aos::RetWithError<Poco::Dynamic::Var> ReadJsonFromFile(const std::string& path);
+
 /**
  * Finds value of the json by path
  *

src/common/utils/tests/json.cpp

@@ -5,6 +5,9 @@
  * SPDX-License-Identifier: Apache-2.0
  */
 
+#include <unistd.h>
+
+#include <cerrno>
 #include <fstream>
 
 #include <Poco/JSON/Object.h>
@@ -284,6 +287,45 @@ TEST_F(JsonTest, WriteJsonToFileFails)
     EXPECT_EQ(WriteJsonToFile(object, path), aos::ErrorEnum::eFailed);
 }
 
+TEST_F(JsonTest, ReadJsonFromFileSucceeds)
+{
+    const std::string path = "read_json_from_file.json";
+
+    Poco::JSON::Object::Ptr object = new Poco::JSON::Object;
+    object->set("key", "value");
+
+    ASSERT_EQ(WriteJsonToFile(object, path), aos::ErrorEnum::eNone);
+
+    auto [var, err] = ReadJsonFromFile(path);
+
+    EXPECT_EQ(err, aos::ErrorEnum::eNone);
+    EXPECT_EQ(var.extract<Poco::JSON::Object::Ptr>()->getValue<std::string>("key"), "value");
+
+    std::remove(path.c_str());
+}
+
+TEST_F(JsonTest, ReadJsonFromFileNotFound)
+{
+    auto [var, err] = ReadJsonFromFile("read_json_from_file_missing.json");
+
+    EXPECT_EQ(err, aos::ErrorEnum::eNotFound);
+}
+
+TEST_F(JsonTest, ReadJsonFromFileReturnsErrnoAsIs)
+{
+    const std::string path = "read_json_from_file_link_loop.json";
+
+    std::remove(path.c_str());
+
+    ASSERT_EQ(symlink(path.c_str(), path.c_str()), 0);
+
+    auto [var, err] = ReadJsonFromFile(path);
+
+    EXPECT_EQ(err.Code(), ELOOP);
+
+    std::remove(path.c_str());
+}
+
 TEST_F(JsonTest, ToJSONArray)
 {
     auto array