sizeof() can return a platform-dependent result

[jmjatlanta]

As stated here: https://github.com/bitshares/bitshares-core/issues/995#issuecomment-450638713 , sizeof() can return a platform-dependent result. This can endanger consensus, if one node rejects a (block | transaction) due to size, but another accepts it.

In all code that limits or rejects due to size, a platform-independent size must be calculated.

Impacts

• [ ] API (the application programming interface)
• [ ] Build (the build process or something prior to compiled code)
• [ ] CLI (the command line wallet)
• [ ] Deployment (the deployment process after building such as Docker, Travis, etc.)
• [ ] DEX (the Decentralized EXchange, market engine, etc.)
• [x] P2P (the peer-to-peer network for transaction/block propagation)
• [ ] Performance (system or user efficiency, etc.)
• [x] Protocol (the blockchain logic, consensus, validation, etc.)
• [ ] Security (the security of system or user data, etc.)
• [ ] UX (the User Experience)
• [ ] Other (please add below)

Steps To Reproduce tbd

Expected Behavior Blocks or transactions should be accepted or rejected independent of the node platform.

CORE TEAM TASK LIST

• [ ] Evaluate / Prioritize Bug Report
• [ ] Refine User Stories / Requirements
• [ ] Define Test Cases
• [ ] Design / Develop Solution
• [ ] Perform QA/Testing
• [ ] Update Documentation

[jmjatlanta]

64bit Linux: The size of a(n) int is: 4 The size of a(n) long is: 8 The size of a(n) long long is: 8 The size of a(n) unsigned long is: 8 The size of a(n) void* is: 8 The size of a(n) std::string is: 32

64bit macOS: The size of a(n) int is: 4 The size of a(n) long is: 8 The size of a(n) long long is: 8 The size of a(n) unsigned long is: 8 The size of a(n) void* is: 8 The size of a(n) std::string is: 24

64bit WIndows 10 The size of a(n) int is: 4 The size of a(n) long is: 4 The size of a(n) long long is: 8 The size of a(n) unsigned long is: 4 The size of a(n) void* is: 4 The size of a(n) std::string is: 28

Related PR: https://github.com/bitshares/bitshares-fc/pull/100

[jmjatlanta]

From what I can see, blocks are rejected if fc::raw::pack_size is greater than global_properties.parameters.maximum_block_size. Need to verify that pack_size reports that the same block is the same size regardless of platform, which I believe to be the case, but will investigate.

Transactions can also be rejected if fc::raw::pack_size is greater than global_properties.maximum_transaction_size. As above, we need to verify that packed_size reports the same number regardless of platform. See #1573

[abitmore]

E.G. code in memo.cpp: https://github.com/bitshares/bitshares-core/blob/173ff3d27a4ca076a62bffdcd22d8f315b239a68/libraries/protocol/memo.cpp#L76-L90

BTW the combination of a (uint32_t &) conversion and a native_to_little() call looks suspicious.