Check the behavior when contract tries to open a file and fix it

[da1suk8]

• Check for errors when a contract tries to open a file.
• Contract that should not be stored (contract that try to open a file) is stored.

This contract should not be stored and needs to be fixed.

[da1suk8]

• Goal : The contract, which should not be stored or executed, can be stored and executed in line/cosmwasm, so check and modify it.

  • Add the following code and check by execute(instantiate, migrate), query

    1. line/cosmwasm(main branch)
    2. cosmwasm/cosmwasm
    3. line/cosmwasm(dynamic_link branch)

  • If there is a difference between the above results, correct the behavior (where should it fall? etc...) and correct it.

  • If there is no difference as a result of the above, correct the behavior (where should it fall? etc...) and where can it actually be executed? If it seems to be possible to fix it, then fix it.

use std::fs::File;
use std::io::prelude::*;
   
fn check_store(filename: String) {
    let mut f = File::open(filename).expect("file not found");
   
    let mut contents = String::new();
    f.read_to_string(&mut contents)
        .expect("something went wrong reading the file");
 
}

[da1suk8]

Error in cosmwasm/cosmwasm

raw_log: 'failed to execute message; message index: 0: Error calling the VM: Error
executing Wasm: Wasmer runtime error: RuntimeError: Aborted: panicked at ''file
not found: Error { kind: Unsupported, message: "operation not supported on this
platform" }'', src/contract.rs:43:38: execute wasm contract failed'

Error in line/cosmwasm

{"height":"742","txhash":"48C091A7013110541E135BADB507F3FF4DBBF909C0DB830A192BDC88797150D7","codespace":"wasm","code":5,"data":"","raw_log":"failed to execute message; message index: 0: Error calling the VM: Error executing Wasm: Wasmer runtime error: RuntimeError: unreachable: execute wasm contract failed","logs":[],"info":"","gas_wanted":"200000","gas_used":"83203","tx":null,"timestamp":"","events":[{"type":"tx","attributes":[{"key":"ZmVl","value":"","index":false}]},{"type":"tx","attributes":[{"key":"YWNjX3NlcQ==","value":"bGluazF0d3NmbXVqMjhuZHBoNTRrNG53OGNyd3U4aDljOG1oM3J0eDcwNS8xMg==","index":false}]},{"type":"tx","attributes":[{"key":"c2lnbmF0dXJl","value":"L2xWMEt2TUxUdHNZRkNESjV6ZzJGWUhRQTZlWEJRODJibXVFQWVyWVFDcGd6WlFtWENNdFRENy9JblVZWFFyamVsSENxa2l5OXV0TFdmT0JGTzdaUlE9PQ==","index":false}]}],"index":0}

[da1suk8]

Conculusion

In cosmwasm/cosmwasm(line/cosmwasm), target=wasm32-unknown-unknown is used, so that std::fs functions return runtime errors at executing. Therefore, as for File::open, it cannot be executed.

• about std::fs of wasm32-unknown-unknown
• wasm32-unknown-unknown
• std: Add a new wasm32-unknown-unknown target rust-lang/rust#45905
• https://github.com/rust-lang/rust/blob/a7851767419e56280110fe2859bbc15d5cbdd468/library/std/src/sys/wasm/mod.rs#L1-L15
• https://github.com/rust-lang/rust/blob/8c6ce6b91b172f77c795a74bfeaf74b865146b3f/library/std/src/sys/unsupported/common.rs#L19-L24
• https://crates.io/crates/platforms

In addition, when compiled with target=wasm32-wasi using WASI, for which File::open, etc. is standardized, and tried to do store of wasm, an error occurred in validation. (EXCEPT dynamic link branch)

raw_log: 'failed to execute message; message index: 0: Error calling the VM: Error
  during static Wasm validation: Wasm contract requires unsupported import: "wasi_snapshot_preview1.fd_filestat_get".
  Required imports: {"env.addr_canonicalize", "env.addr_humanize", "env.addr_validate",
  "env.db_next", "env.db_read", "env.db_remove", "env.db_scan", "env.db_write", "env.debug",
  "env.ed25519_batch_verify", ... 15 more}. Available imports: ["env.abort", "env.db_read",
  "env.db_write", "env.db_remove", "env.addr_validate", "env.addr_canonicalize", "env.addr_humanize",
  "env.secp256k1_verify", "env.secp256k1_recover_pubkey", "env.ed25519_verify", "env.ed25519_batch_verify",
  "env.debug", "env.query_chain", "env.db_scan", "env.db_next"].: create wasm contract
  failed'

• https://github.com/CosmWasm/cosmwasm/blob/main/packages/vm/src/compatibility.rs#L54-L62
• https://github.com/CosmWasm/cosmwasm/blob/main/packages/vm/src/compatibility.rs#L146-L171
• https://github.com/CosmWasm/cosmwasm/blob/main/packages/vm/src/compatibility.rs#L10-L30

Although there is a difference in the error contents between cosmwasm/cosmwasm and line/cosmwasm, the location causing the error is the same, and adding an abort feature as shown below will result in the same error contents.

• Implement panic handler CosmWasm/cosmwasm#1296

Found task

• Check and fix on custom env module name #243

[loloicci]

@da1suk8 Could you try the wasm32-wasi version WASM in the dynamic link branch version LBM? The error "Wasm contract requires unsupported import" seems not to occur in dynamic link branch. It is because of this change (https://github.com/line/cosmwasm/blame/dynamic_link/packages/vm/src/compatibility.rs#L116).

[da1suk8]

The following error occurred during instantiate in the dynamic link branch. It seems that execution itself is not possible.

{"height":"789","txhash":"85A99B66B0B3A58D19947F2A7A81FDA5882AFA95BD6937D2FA5E55EA24BECD76","codespace":"wasm","code":4,"data":"","raw_log":"failed to execute message; message index: 0: Error calling the VM: Error executing Wasm: Wasmer runtime error: RuntimeError: Error in guest/host communication: Got an invalid region: Got a zero Wasm address in the offset: instantiate wasm contract failed","logs":[],"info":"","gas_wanted":"10000000000","gas_used":"63259","tx":null,"timestamp":""}

Also, the following modification(https://github.com/line/cosmwasm/blame/dynamic_link/packages/vm/src/compatibility.rs#L116) to the dynamic link branch causes functions such as wasi_snapshot_preview1.fd_filestat_get to be judged as functions used by dynamic link when compiled by wasm32-wasi, etc. I have created a new issue.