From b3d97482475eee5a9e9eb55c6ce92dfb4d1ca38f Mon Sep 17 00:00:00 2001
From: Andrei Maiboroda <andrei@ethereum.org>
Date: Wed, 29 Sep 2021 20:34:43 +0200
Subject: [PATCH] Make EOF header validation more generic (supporting any
 sections)

---
 lib/evmone/eof.cpp | 28 ++++++++++++++++++----------
 1 file changed, 18 insertions(+), 10 deletions(-)

diff --git a/lib/evmone/eof.cpp b/lib/evmone/eof.cpp
index a6601e22a2..e05c4a1357 100644
--- a/lib/evmone/eof.cpp
+++ b/lib/evmone/eof.cpp
@@ -16,8 +16,11 @@ constexpr uint8_t MAGIC = 0x00;
 constexpr uint8_t TERMINATOR = 0x00;
 constexpr uint8_t CODE_SECTION = 0x01;
 constexpr uint8_t DATA_SECTION = 0x02;
+constexpr uint8_t MAX_SECTION = DATA_SECTION;
 
-std::pair<EOF1Header, EOFValidationErrror> validate_eof_headers(bytes_view code) noexcept
+using EOFSectionHeaders = std::array<size_t, MAX_SECTION + 1>;
+
+std::pair<EOFSectionHeaders, EOFValidationErrror> validate_eof_headers(bytes_view code) noexcept
 {
     enum class State
     {
@@ -28,7 +31,7 @@ std::pair<EOF1Header, EOFValidationErrror> validate_eof_headers(bytes_view code)
 
     auto state = State::section_id;
     uint8_t section_id = 0;
-    size_t section_sizes[3] = {0, 0, 0};
+    EOFSectionHeaders section_headers{};
     const auto code_end = code.end();
     auto it = code.begin() + sizeof(MAGIC) + 2;  // FORMAT + MAGIC + VERSION
     while (it != code_end && state != State::terminated)
@@ -41,19 +44,19 @@ std::pair<EOF1Header, EOFValidationErrror> validate_eof_headers(bytes_view code)
             switch (section_id)
             {
             case TERMINATOR:
-                if (section_sizes[CODE_SECTION] == 0)
+                if (section_headers[CODE_SECTION] == 0)
                     return {{}, EOFValidationErrror::code_section_missing};
                 state = State::terminated;
                 break;
             case DATA_SECTION:
-                if (section_sizes[CODE_SECTION] == 0)
+                if (section_headers[CODE_SECTION] == 0)
                     return {{}, EOFValidationErrror::code_section_missing};
-                if (section_sizes[DATA_SECTION] != 0)
+                if (section_headers[DATA_SECTION] != 0)
                     return {{}, EOFValidationErrror::multiple_data_sections};
                 state = State::section_size;
                 break;
             case CODE_SECTION:
-                if (section_sizes[CODE_SECTION] != 0)
+                if (section_headers[CODE_SECTION] != 0)
                     return {{}, EOFValidationErrror::multiple_code_sections};
                 state = State::section_size;
                 break;
@@ -73,7 +76,7 @@ std::pair<EOF1Header, EOFValidationErrror> validate_eof_headers(bytes_view code)
             if (section_size == 0)
                 return {{}, EOFValidationErrror::zero_section_size};
 
-            section_sizes[section_id] = section_size;
+            section_headers[section_id] = section_size;
             state = State::section_id;
             break;
         }
@@ -87,17 +90,22 @@ std::pair<EOF1Header, EOFValidationErrror> validate_eof_headers(bytes_view code)
     if (state != State::terminated)
         return {{}, EOFValidationErrror::section_headers_not_terminated};
 
-    const auto section_bodies_size = section_sizes[CODE_SECTION] + section_sizes[DATA_SECTION];
+    const auto section_bodies_size = section_headers[CODE_SECTION] + section_headers[DATA_SECTION];
     const auto remaining_code_size = static_cast<size_t>(code_end - it);
     if (section_bodies_size != remaining_code_size)
         return {{}, EOFValidationErrror::invalid_section_bodies_size};
 
-    return {{section_sizes[0], section_sizes[1]}, EOFValidationErrror::success};
+    return {section_headers, EOFValidationErrror::success};
 }
 
 std::pair<EOF1Header, EOFValidationErrror> validate_eof1(bytes_view code) noexcept
 {
-    return validate_eof_headers(code);
+    const auto [section_headers, error] = validate_eof_headers(code);
+    if (error != EOFValidationErrror::success)
+        return {{}, error};
+
+    const EOF1Header header{section_headers[CODE_SECTION], section_headers[DATA_SECTION]};
+    return {header, EOFValidationErrror::success};
 }
 }  // namespace