Added security checks for symlinks
Added security checks which prevents service from interacting with
symlinks. It is not possible to list/delete/read/write to symlinks.
Tested:
Added unit tests which confirm that:
- Symlinks cannot be removed
- Symlinks are not listed
- Symlinks cannot be overwritten
- Symlinks cannot be read
Signed-off-by: Krzysztof Grobelny <krzysztof.grobelny@intel.com>
Change-Id: I50d6d10dac81fd454e7e30520a7c47d5146be58c
diff --git a/src/persistent_json_storage.cpp b/src/persistent_json_storage.cpp
index 896c8a9..0dc66ad 100644
--- a/src/persistent_json_storage.cpp
+++ b/src/persistent_json_storage.cpp
@@ -5,6 +5,8 @@
#include <fstream>
#include <stdexcept>
+using namespace std::literals::string_literals;
+
PersistentJsonStorage::PersistentJsonStorage(const DirectoryPath& directory) :
directory(directory)
{}
@@ -28,6 +30,8 @@
", ec=" + std::to_string(ec.value()) + ": " + ec.message());
}
+ assertThatPathIsNotSymlink(path);
+
std::ofstream file(path);
file << data;
if (!file)
@@ -48,6 +52,12 @@
bool PersistentJsonStorage::remove(const FilePath& filePath)
{
const auto path = join(directory, filePath);
+
+ if (std::filesystem::is_symlink(path))
+ {
+ return false;
+ }
+
std::error_code ec;
auto removed = std::filesystem::remove(path, ec);
@@ -79,6 +89,7 @@
try
{
+ assertThatPathIsNotSymlink(path);
std::ifstream file(path);
file >> result;
}
@@ -103,7 +114,7 @@
for (const auto& p :
std::filesystem::recursive_directory_iterator(directory))
{
- if (p.is_regular_file())
+ if (p.is_regular_file() && !p.is_symlink())
{
auto item = std::filesystem::relative(p.path(), directory);
result.emplace_back(std::move(item));
@@ -134,3 +145,14 @@
{
return std::filesystem::exists(join(directory, subPath));
}
+
+void PersistentJsonStorage::assertThatPathIsNotSymlink(
+ const std::filesystem::path& path)
+{
+ if (std::filesystem::is_symlink(path))
+ {
+ throw std::runtime_error(
+ "Source/Target file is a symlink! Operation canceled on path "s +
+ path.c_str());
+ }
+}
diff --git a/src/persistent_json_storage.hpp b/src/persistent_json_storage.hpp
index 2b0f365..064a4c6 100644
--- a/src/persistent_json_storage.hpp
+++ b/src/persistent_json_storage.hpp
@@ -19,4 +19,5 @@
static std::filesystem::path join(const std::filesystem::path&,
const std::filesystem::path&);
static void limitPermissions(const std::filesystem::path& path);
+ static void assertThatPathIsNotSymlink(const std::filesystem::path& path);
};
diff --git a/tests/src/test_persistent_json_storage.cpp b/tests/src/test_persistent_json_storage.cpp
index 7ddc5b6..8e67a2e 100644
--- a/tests/src/test_persistent_json_storage.cpp
+++ b/tests/src/test_persistent_json_storage.cpp
@@ -1,6 +1,8 @@
#include "helpers.hpp"
#include "persistent_json_storage.hpp"
+#include <fstream>
+
#include "gmock/gmock.h"
#include "gtest/gtest.h"
@@ -111,3 +113,69 @@
{
ASSERT_THAT(sut.load(fileName), Eq(std::nullopt));
}
+
+class TestPersistentJsonStorageWithSymlink : public TestPersistentJsonStorage
+{
+ public:
+ TestPersistentJsonStorageWithSymlink()
+ {
+ std::ofstream file(dummyReportPath);
+ file << "{}";
+ file.close();
+
+ std::filesystem::create_directories(std::filesystem::path(directory) /
+ "report");
+ std::filesystem::create_symlink(dummyReportPath,
+ std::filesystem::path(directory) /
+ "report/symlink.json");
+ }
+
+ static void SetUpTestSuite()
+ {
+ TestPersistentJsonStorage::SetUpTestSuite();
+ ASSERT_FALSE(std::filesystem::exists(dummyReportPath));
+ }
+
+ void TearDown() override
+ {
+ TestPersistentJsonStorage::TearDown();
+ if (std::filesystem::exists(dummyReportPath))
+ {
+ std::filesystem::remove(dummyReportPath);
+ }
+ }
+
+ static const std::filesystem::path dummyReportPath;
+};
+
+const std::filesystem::path
+ TestPersistentJsonStorageWithSymlink::dummyReportPath =
+ std::filesystem::temp_directory_path() / "report";
+
+TEST_F(TestPersistentJsonStorageWithSymlink, symlinksAreNotListed)
+{
+ ASSERT_THAT(sut.list(), UnorderedElementsAre());
+}
+
+TEST_F(TestPersistentJsonStorageWithSymlink, throwsWhenStoreTargetIsSymlink)
+{
+ ASSERT_THROW(
+ sut.store(FilePath("report/symlink.json"), nlohmann::json("data")),
+ std::runtime_error);
+
+ ASSERT_THAT(sut.list(), UnorderedElementsAre());
+}
+
+TEST_F(TestPersistentJsonStorageWithSymlink, returnsNulloptWhenFileIsSymlink)
+{
+ ASSERT_THAT(sut.load(FilePath("report/symlink.json")), Eq(std::nullopt));
+}
+
+TEST_F(TestPersistentJsonStorageWithSymlink,
+ returnsFalseWhenTryingToDeleteSymlink)
+{
+ EXPECT_THAT(sut.remove(FilePath("report/symlink.json")), Eq(false));
+ EXPECT_TRUE(std::filesystem::exists(std::filesystem::path(directory) /
+ "report/symlink.json"));
+ EXPECT_TRUE(std::filesystem::exists(dummyReportPath));
+}