From 44155da2d8326e5295ddf1b503a82cfc0d4228b6 Mon Sep 17 00:00:00 2001
From: levlam <levlam@telegram.org>
Date: Thu, 11 Jun 2020 18:21:18 +0300
Subject: [PATCH] Fix BinlogEvent size checks.

GitOrigin-RevId: 0fe66f0be34fd15618c3f19edaeec5e64072c170
---
 tddb/td/db/binlog/Binlog.cpp      |  4 ++--
 tddb/td/db/binlog/Binlog.h        |  2 --
 tddb/td/db/binlog/BinlogEvent.cpp | 16 ++++++++--------
 tddb/td/db/binlog/BinlogEvent.h   | 11 ++++++-----
 4 files changed, 16 insertions(+), 17 deletions(-)

diff --git a/tddb/td/db/binlog/Binlog.cpp b/tddb/td/db/binlog/Binlog.cpp
index ae3cde0a3..c663470dc 100644
--- a/tddb/td/db/binlog/Binlog.cpp
+++ b/tddb/td/db/binlog/Binlog.cpp
@@ -118,10 +118,10 @@ class BinlogReader {
       it.advance(4, MutableSlice(buf, 4));
       size_ = static_cast<size_t>(TlParser(Slice(buf, 4)).fetch_int());
 
-      if (size_ > MAX_EVENT_SIZE) {
+      if (size_ > BinlogEvent::MAX_SIZE) {
         return Status::Error(PSLICE() << "Too big event " << tag("size", size_));
       }
-      if (size_ < MIN_EVENT_SIZE) {
+      if (size_ < BinlogEvent::MIN_SIZE) {
         return Status::Error(PSLICE() << "Too small event " << tag("size", size_));
       }
       if (size_ % 4 != 0) {
diff --git a/tddb/td/db/binlog/Binlog.h b/tddb/td/db/binlog/Binlog.h
index 548d1d754..f5197b7ec 100644
--- a/tddb/td/db/binlog/Binlog.h
+++ b/tddb/td/db/binlog/Binlog.h
@@ -148,8 +148,6 @@ class Binlog {
   bool need_sync_{false};
   enum class State { Empty, Load, Reindex, Run } state_{State::Empty};
 
-  static constexpr uint32 MAX_EVENT_SIZE = 65536;
-
   Result<FileFd> open_binlog(const string &path, int32 flags);
   size_t flush_events_buffer(bool force);
   void do_add_event(BinlogEvent &&event);
diff --git a/tddb/td/db/binlog/BinlogEvent.cpp b/tddb/td/db/binlog/BinlogEvent.cpp
index c4a819932..749deec87 100644
--- a/tddb/td/db/binlog/BinlogEvent.cpp
+++ b/tddb/td/db/binlog/BinlogEvent.cpp
@@ -23,13 +23,13 @@ Status BinlogEvent::init(BufferSlice &&raw_event, bool check_crc) {
   type_ = parser.fetch_int();
   flags_ = parser.fetch_int();
   extra_ = parser.fetch_long();
-  CHECK(size_ >= MIN_EVENT_SIZE);
-  auto slice_data = parser.fetch_string_raw<Slice>(size_ - MIN_EVENT_SIZE);
+  CHECK(size_ >= MIN_SIZE);
+  auto slice_data = parser.fetch_string_raw<Slice>(size_ - MIN_SIZE);
   data_ = MutableSlice(const_cast<char *>(slice_data.begin()), slice_data.size());
   crc32_ = static_cast<uint32>(parser.fetch_int());
   if (check_crc) {
-    CHECK(size_ >= EVENT_TAIL_SIZE);
-    auto calculated_crc = crc32(raw_event.as_slice().truncate(size_ - EVENT_TAIL_SIZE));
+    CHECK(size_ >= TAIL_SIZE);
+    auto calculated_crc = crc32(raw_event.as_slice().truncate(size_ - TAIL_SIZE));
     if (calculated_crc != crc32_) {
       return Status::Error(PSLICE() << "crc mismatch " << tag("actual", format::as_hex(calculated_crc))
                                     << tag("expected", format::as_hex(crc32_)) << public_to_string());
@@ -52,7 +52,7 @@ Status BinlogEvent::validate() const {
 }
 
 BufferSlice BinlogEvent::create_raw(uint64 id, int32 type, int32 flags, const Storer &storer) {
-  auto raw_event = BufferSlice{storer.size() + MIN_EVENT_SIZE};
+  auto raw_event = BufferSlice{storer.size() + MIN_SIZE};
 
   TlStorerUnsafe tl_storer(raw_event.as_slice().ubegin());
   tl_storer.store_int(narrow_cast<int32>(raw_event.size()));
@@ -61,11 +61,11 @@ BufferSlice BinlogEvent::create_raw(uint64 id, int32 type, int32 flags, const St
   tl_storer.store_int(flags);
   tl_storer.store_long(0);
 
-  CHECK(tl_storer.get_buf() == raw_event.as_slice().ubegin() + EVENT_HEADER_SIZE);
+  CHECK(tl_storer.get_buf() == raw_event.as_slice().ubegin() + HEADER_SIZE);
   tl_storer.store_storer(storer);
 
-  CHECK(tl_storer.get_buf() == raw_event.as_slice().uend() - EVENT_TAIL_SIZE);
-  tl_storer.store_int(::td::crc32(raw_event.as_slice().truncate(raw_event.size() - EVENT_TAIL_SIZE)));
+  CHECK(tl_storer.get_buf() == raw_event.as_slice().uend() - TAIL_SIZE);
+  tl_storer.store_int(::td::crc32(raw_event.as_slice().truncate(raw_event.size() - TAIL_SIZE)));
 
   return raw_event;
 }
diff --git a/tddb/td/db/binlog/BinlogEvent.h b/tddb/td/db/binlog/BinlogEvent.h
index 038c8cd9b..ad044603d 100644
--- a/tddb/td/db/binlog/BinlogEvent.h
+++ b/tddb/td/db/binlog/BinlogEvent.h
@@ -32,11 +32,6 @@ inline auto EmptyStorer() {
   return create_default_storer(impl);
 }
 
-static constexpr size_t MAX_EVENT_SIZE = 1 << 24;
-static constexpr size_t EVENT_HEADER_SIZE = 4 + 8 + 4 + 4 + 8;
-static constexpr size_t EVENT_TAIL_SIZE = 4;
-static constexpr size_t MIN_EVENT_SIZE = EVENT_HEADER_SIZE + EVENT_TAIL_SIZE;
-
 extern int32 VERBOSITY_NAME(binlog);
 
 struct BinlogDebugInfo {
@@ -46,6 +41,7 @@ struct BinlogDebugInfo {
   const char *file{""};
   int line{0};
 };
+
 inline StringBuilder &operator<<(StringBuilder &sb, const BinlogDebugInfo &info) {
   if (info.line == 0) {
     return sb;
@@ -54,6 +50,11 @@ inline StringBuilder &operator<<(StringBuilder &sb, const BinlogDebugInfo &info)
 }
 
 struct BinlogEvent {
+  static constexpr size_t MAX_SIZE = 1 << 24;
+  static constexpr size_t HEADER_SIZE = 4 + 8 + 4 + 4 + 8;
+  static constexpr size_t TAIL_SIZE = 4;
+  static constexpr size_t MIN_SIZE = HEADER_SIZE + TAIL_SIZE;
+
   int64 offset_;
 
   uint32 size_;