From db05664f5792cac82eaeeaaf27c4b35db5018a67 Mon Sep 17 00:00:00 2001
From: Matt Witherspoon <32485495+spoonincode@users.noreply.github.com>
Date: Wed, 7 Feb 2018 12:45:20 -0500
Subject: [PATCH] Place wasm_constraints in constexpr variables

Place some of the wasm_constraints in constexpr variables that can be referred to from elsewhere
---
 .../eosio/chain/wasm_eosio_constraints.hpp     |  8 ++++++++
 libraries/chain/wasm_eosio_constraints.cpp     | 18 +++++++++---------
 2 files changed, 17 insertions(+), 9 deletions(-)

diff --git a/libraries/chain/include/eosio/chain/wasm_eosio_constraints.hpp b/libraries/chain/include/eosio/chain/wasm_eosio_constraints.hpp
index 323f3cd14..c3e38b979 100644
--- a/libraries/chain/include/eosio/chain/wasm_eosio_constraints.hpp
+++ b/libraries/chain/include/eosio/chain/wasm_eosio_constraints.hpp
@@ -6,6 +6,14 @@ namespace IR {
 
 namespace eosio { namespace chain {
 
+namespace wasm_constraints {
+   //Be aware that some of these are required to be a multiple of some internal number
+   constexpr unsigned maximum_linear_memory      = 1024*1024;  //bytes
+   constexpr unsigned maximum_mutable_globals    = 1024;       //bytes
+   constexpr unsigned maximum_table_elements     = 1024;       //elements
+   constexpr unsigned maximum_linear_memory_init = 64*1024;    //bytes
+}
+
 //Throws if something in the module violates
 void validate_eosio_wasm_constraints(const IR::Module& m);
 
diff --git a/libraries/chain/wasm_eosio_constraints.cpp b/libraries/chain/wasm_eosio_constraints.cpp
index 515448558..d755c8b5a 100644
--- a/libraries/chain/wasm_eosio_constraints.cpp
+++ b/libraries/chain/wasm_eosio_constraints.cpp
@@ -29,7 +29,7 @@ struct eosio_constraints_visitor : public nop_opcode_visitor {
    // an 8 byte data type, that's fine. There will be enough of a guard on the end
    // of 1MiB where it's not a problem
    void fail_large_offset(U32 offset) {
-      if(offset >= 1024*1024)
+      if(offset >= wasm_constraints::maximum_linear_memory)
          FC_THROW_EXCEPTION(wasm_execution_error, "Smart contract used an invalid large memory store/load offset");
    }
    void i32_load     (LoadOrStoreImm<2> imm) override { fail_large_offset(imm.offset); }
@@ -65,18 +65,18 @@ struct eosio_constraints_visitor : public nop_opcode_visitor {
 };
 
 void validate_eosio_wasm_constraints(const Module& m) {
-   if(m.memories.defs.size() && m.memories.defs[0].type.size.min > 16)
-      FC_THROW_EXCEPTION(wasm_execution_error, "Smart contract initial memory size must be less than or equal to 1MiB");
+   if(m.memories.defs.size() && m.memories.defs[0].type.size.min > wasm_constraints::maximum_linear_memory/(64*1024))
+      FC_THROW_EXCEPTION(wasm_execution_error, "Smart contract initial memory size must be less than or equal to ${k}KiB", ("k", wasm_constraints::maximum_linear_memory/1024));
 
    for(const DataSegment& ds : m.dataSegments) {
       if(ds.baseOffset.type != InitializerExpression::Type::i32_const)
          FC_THROW_EXCEPTION(wasm_execution_error, "Smart contract has unexpected memory base offset type");
-      if(static_cast<uint32_t>(ds.baseOffset.i32) + ds.data.size() > 64*1024)
-         FC_THROW_EXCEPTION(wasm_execution_error, "Smart contract data segments must lie in first 64KiB");
+      if(static_cast<uint32_t>(ds.baseOffset.i32) + ds.data.size() > wasm_constraints::maximum_linear_memory_init)
+         FC_THROW_EXCEPTION(wasm_execution_error, "Smart contract data segments must lie in first ${k}KiB", ("k", wasm_constraints::maximum_linear_memory_init/1024));
    }
 
-   if(m.tables.defs.size() && m.tables.defs[0].type.size.min > 1024)
-      FC_THROW_EXCEPTION(wasm_execution_error, "Smart contract table limited to 1024 elements");
+   if(m.tables.defs.size() && m.tables.defs[0].type.size.min > wasm_constraints::maximum_table_elements)
+      FC_THROW_EXCEPTION(wasm_execution_error, "Smart contract table limited to ${t} elements", ("t", wasm_constraints::maximum_table_elements));
 
    unsigned mutable_globals_total_size = 0;
    for(const GlobalDef& global_def : m.globals.defs) {
@@ -94,8 +94,8 @@ void validate_eosio_wasm_constraints(const Module& m) {
             mutable_globals_total_size += 4;
       }
    }
-   if(mutable_globals_total_size > 1024)
-      FC_THROW_EXCEPTION(wasm_execution_error, "Smart contract has more than 1KiB of mutable globals");
+   if(mutable_globals_total_size > wasm_constraints::maximum_mutable_globals)
+      FC_THROW_EXCEPTION(wasm_execution_error, "Smart contract has more than ${k} bytes of mutable globals", ("k", wasm_constraints::maximum_mutable_globals));
 
    //Some of the OperatorDecoderStream users inside of WAVM track the control stack and quit parsing from
    // OperatorDecoderStream when the control stack is empty (since that would indicate unreachable code).
-- 
GitLab