Final part on compatibility layer: LOGBROKER-7215

ref:777c67aadbf705d19034a09a792b2df61ba53697

4 files changed, 307 insertions, 0 deletions

diff --git a/library/cpp/string_utils/secret_string/CMakeLists.txt b/library/cpp/string_utils/secret_string/CMakeLists.txt
new file mode 100644
index 0000000000..e801dca812
--- /dev/null
+++ b/library/cpp/string_utils/secret_string/CMakeLists.txt
@@ -0,0 +1,18 @@
+
+# This file was gererated by the build system used internally in the Yandex monorepo.
+# Only simple modifications are allowed (adding source-files to targets, adding simple properties
+# like target_include_directories). These modifications will be ported to original
+# ya.make files by maintainers. Any complex modifications which can't be ported back to the
+# original buildsystem will not be accepted.
+
+
+
+add_library(cpp-string_utils-secret_string)
+target_link_libraries(cpp-string_utils-secret_string PUBLIC
+  contrib-libs-cxxsupp
+  yutil
+  cpp-string_utils-ztstrbuf
+)
+target_sources(cpp-string_utils-secret_string PRIVATE
+  ${CMAKE_SOURCE_DIR}/library/cpp/string_utils/secret_string/secret_string.cpp
+)
diff --git a/library/cpp/string_utils/secret_string/secret_string.cpp b/library/cpp/string_utils/secret_string/secret_string.cpp
new file mode 100644
index 0000000000..3b68d3cd27
--- /dev/null
+++ b/library/cpp/string_utils/secret_string/secret_string.cpp
@@ -0,0 +1,68 @@
+#include "secret_string.h"
+
+#include <util/system/madvise.h>
+
+namespace NSecretString {
+    TSecretString::TSecretString(TStringBuf value) {
+        Init(value);
+    }
+
+    TSecretString::~TSecretString() {
+        try {
+            Clear();
+        } catch (...) {
+        }
+    }
+
+    TSecretString& TSecretString::operator=(const TSecretString& o) {
+        if (&o == this) {
+            return *this;
+        }
+
+        Init(o.Value_);
+
+        return *this;
+    }
+
+    /**
+     * It is not honest "move". Actually it is copy-assignment with cleaning of other instance.
+     * This way allowes to avoid side effects of string optimizations:
+     *   Copy-On-Write or Short-String-Optimization
+     */
+    TSecretString& TSecretString::operator=(TSecretString&& o) {
+        if (&o == this) {
+            return *this;
+        }
+
+        Init(o.Value_);
+        o.Clear();
+
+        return *this;
+    }
+
+    TSecretString& TSecretString::operator=(const TStringBuf o) {
+        Init(o);
+
+        return *this;
+    }
+
+    void TSecretString::Init(TStringBuf value) {
+        Clear();
+        if (value.empty()) {
+            return;
+        }
+
+        Value_ = value;
+        MadviseExcludeFromCoreDump(Value_);
+    }
+
+    void TSecretString::Clear() {
+        if (Value_.empty()) {
+            return;
+        }
+
+        SecureZero((void*)Value_.data(), Value_.size());
+        MadviseIncludeIntoCoreDump(Value_);
+        Value_.clear();
+    }
+}
diff --git a/library/cpp/string_utils/secret_string/secret_string.h b/library/cpp/string_utils/secret_string/secret_string.h
new file mode 100644
index 0000000000..fdb9f6a85c
--- /dev/null
+++ b/library/cpp/string_utils/secret_string/secret_string.h
@@ -0,0 +1,74 @@
+#pragma once
+
+#include <library/cpp/string_utils/ztstrbuf/ztstrbuf.h>
+
+#include <util/generic/string.h>
+
+namespace NSecretString {
+    /**
+     * TSecretString allowes to store some long lived secrets in "secure" storage in memory.
+     * Common usage:
+     *  1) read secret value from disk/env/etc
+     *  2) put it into TSecretString
+     *  3) destory secret copy from 1)
+     *
+     * Useful scenerios for TSecretString:
+     *   - in memory only tasks: using key to create crypto signature;
+     *   - rare network cases: db password on connection or OAuth token in background tasks.
+     *     These cases disclosure the secret
+     *       because of sending it over network with some I/O frameworks.
+     *     Usually such frameworks copy input params to provide network protocol: gRPC, for example.
+     *
+     * Supported features:
+     *  1. Exclude secret from core dump.
+     *     madvise(MADV_DONTDUMP) in ctor excludes full memory page from core dump.
+     *     madvise(MADV_DODUMP) in dtor reverts previous action.
+     *  2. Zero memory before free.
+     *
+     * Code dump looks like this:
+(gdb) print s
+$1 = (const TSecretString &) @0x7fff23c4c560: {
+  Value_ = {<TStringBase<TBasicString<char, std::__y1::char_traits<char> >, char, std::__y1::char_traits<char> >> = {
+      static npos = <optimized out>}, Data_ = 0x107c001d8 <error: Cannot access memory at address 0x107c001d8>}}
+     */
+
+    class TSecretString {
+    public:
+        TSecretString() = default;
+        TSecretString(TStringBuf value);
+        ~TSecretString();
+
+        TSecretString(const TSecretString& o)
+            : TSecretString(o.Value())
+        {
+        }
+
+        TSecretString(TSecretString&& o)
+            : TSecretString(o.Value())
+        {
+            o.Clear();
+        }
+
+        TSecretString& operator=(const TSecretString& o);
+        TSecretString& operator=(TSecretString&& o);
+
+        TSecretString& operator=(const TStringBuf o);
+
+        operator TZtStringBuf() const {
+            return Value();
+        }
+
+        // Provides zero terminated string
+        TZtStringBuf Value() const {
+            return TZtStringBuf(Value_);
+        }
+
+    private:
+        // TStringBuf breaks Copy-On-Write to provide correct copy-ctor and copy-assignment
+        void Init(TStringBuf value);
+        void Clear();
+
+    private:
+        TString Value_;
+    };
+}
diff --git a/library/cpp/string_utils/secret_string/ut/secret_string_ut.cpp b/library/cpp/string_utils/secret_string/ut/secret_string_ut.cpp
new file mode 100644
index 0000000000..681b75368f
--- /dev/null
+++ b/library/cpp/string_utils/secret_string/ut/secret_string_ut.cpp
@@ -0,0 +1,147 @@
+#include <library/cpp/string_utils/secret_string/secret_string.h>
+
+#include <library/cpp/testing/unittest/registar.h>
+
+using namespace NSecretString;
+
+Y_UNIT_TEST_SUITE(SecretTest) {
+    Y_UNIT_TEST(Common) {
+        TSecretString s;
+        UNIT_ASSERT_VALUES_EQUAL("", s.Value());
+        UNIT_ASSERT_VALUES_EQUAL("", (TStringBuf)s);
+
+        TSecretString s2("qwerty");
+        UNIT_ASSERT_VALUES_EQUAL("qwerty", s2.Value());
+        UNIT_ASSERT_VALUES_EQUAL("qwerty", (TStringBuf)s2);
+    }
+
+    Y_UNIT_TEST(CopyCtor1) {
+        TSecretString s1("qwerty");
+
+        UNIT_ASSERT_VALUES_EQUAL("qwerty", s1.Value());
+
+        {
+            TSecretString s2(s1);
+            UNIT_ASSERT_VALUES_EQUAL("qwerty", s1.Value());
+            UNIT_ASSERT_VALUES_EQUAL("qwerty", s2.Value());
+        }
+
+        UNIT_ASSERT_VALUES_EQUAL("qwerty", s1.Value());
+    }
+
+    Y_UNIT_TEST(CopyCtor2) {
+        auto s1 = MakeHolder<TSecretString>("qwerty");
+        UNIT_ASSERT_VALUES_EQUAL("qwerty", s1->Value());
+
+        TSecretString s2(*s1);
+        UNIT_ASSERT_VALUES_EQUAL("qwerty", s1->Value());
+        UNIT_ASSERT_VALUES_EQUAL("qwerty", s2.Value());
+
+        s1.Reset();
+        UNIT_ASSERT_VALUES_EQUAL("qwerty", s2.Value());
+    }
+
+    Y_UNIT_TEST(MoveCtor1) {
+        TSecretString s1("qwerty");
+
+        UNIT_ASSERT_VALUES_EQUAL("qwerty", s1.Value());
+
+        {
+            TSecretString s2(std::move(s1));
+            UNIT_ASSERT_VALUES_EQUAL("", s1.Value());
+            UNIT_ASSERT_VALUES_EQUAL("qwerty", s2.Value());
+        }
+
+        UNIT_ASSERT_VALUES_EQUAL("", s1.Value());
+    }
+
+    Y_UNIT_TEST(MoveCtor2) {
+        auto s1 = MakeHolder<TSecretString>("qwerty");
+        UNIT_ASSERT_VALUES_EQUAL("qwerty", s1->Value());
+
+        TSecretString s2(std::move(*s1));
+        UNIT_ASSERT_VALUES_EQUAL("", s1->Value());
+        UNIT_ASSERT_VALUES_EQUAL("qwerty", s2.Value());
+
+        s1.Reset();
+        UNIT_ASSERT_VALUES_EQUAL("qwerty", s2.Value());
+    }
+
+    Y_UNIT_TEST(CopyAssignment1) {
+        TSecretString s1("qwerty");
+
+        UNIT_ASSERT_VALUES_EQUAL("qwerty", s1.Value());
+
+        {
+            TSecretString s2;
+            UNIT_ASSERT_VALUES_EQUAL("", s2.Value());
+
+            s2 = s1;
+            UNIT_ASSERT_VALUES_EQUAL("qwerty", s1.Value());
+            UNIT_ASSERT_VALUES_EQUAL("qwerty", s2.Value());
+        }
+
+        UNIT_ASSERT_VALUES_EQUAL("qwerty", s1.Value());
+    }
+
+    Y_UNIT_TEST(CopyAssignment2) {
+        auto s1 = MakeHolder<TSecretString>("qwerty");
+        UNIT_ASSERT_VALUES_EQUAL("qwerty", s1->Value());
+
+        TSecretString s2;
+        UNIT_ASSERT_VALUES_EQUAL("", s2.Value());
+
+        s2 = *s1;
+        UNIT_ASSERT_VALUES_EQUAL("qwerty", s1->Value());
+        UNIT_ASSERT_VALUES_EQUAL("qwerty", s2.Value());
+
+        s1.Reset();
+        UNIT_ASSERT_VALUES_EQUAL("qwerty", s2.Value());
+
+        TSecretString s3;
+        s2 = s3;
+        UNIT_ASSERT_VALUES_EQUAL("", s2.Value());
+    }
+
+    Y_UNIT_TEST(MoveAssignment1) {
+        TSecretString s1("qwerty");
+
+        UNIT_ASSERT_VALUES_EQUAL("qwerty", s1.Value());
+
+        {
+            TSecretString s2;
+            UNIT_ASSERT_VALUES_EQUAL("", s2.Value());
+
+            s2 = std::move(s1);
+            UNIT_ASSERT_VALUES_EQUAL("", s1.Value());
+            UNIT_ASSERT_VALUES_EQUAL("qwerty", s2.Value());
+        }
+
+        UNIT_ASSERT_VALUES_EQUAL("", s1.Value());
+    }
+
+    Y_UNIT_TEST(MoveAssignment2) {
+        auto s1 = MakeHolder<TSecretString>("qwerty");
+        UNIT_ASSERT_VALUES_EQUAL("qwerty", s1->Value());
+
+        TSecretString s2;
+        UNIT_ASSERT_VALUES_EQUAL("", s2.Value());
+
+        s2 = std::move(*s1);
+        UNIT_ASSERT_VALUES_EQUAL("", s1->Value());
+        UNIT_ASSERT_VALUES_EQUAL("qwerty", s2.Value());
+
+        s1.Reset();
+        UNIT_ASSERT_VALUES_EQUAL("qwerty", s2.Value());
+
+        TSecretString s3;
+        s2 = std::move(s3);
+        UNIT_ASSERT_VALUES_EQUAL("", s2.Value());
+    }
+
+    Y_UNIT_TEST(ZeroTerminated) {
+        TSecretString s("qwerty");
+
+        UNIT_ASSERT_VALUES_EQUAL(s.Value().size(), strlen(s.Value().data()));
+    }
+}