Add heuristic to determine contract origin from Wasm blob #1329

smiasojed · 2023-09-12T14:41:30Z

Summary

Closes #784

[n] y/n | Does it introduce breaking changes?
[n] y/n | Is it dependent on the specific version of ink or pallet-contracts?

Add heuristic to determine contract origin from Wasm blob

Description

Introduced contract-analyze crate with detects the programming language of a smart contract from its WebAssembly (Wasm) binary code.
New crate has been integrated with cargo contract info command, which generates now the output:

          TrieId c7fa1c1ef70d66023c5ecf4a517d39ec908c92d56e5e80af00b222c441dd0f40
       Code Hash 0x2c1388d32d59b87d0a2b6208e3562a11bed29a2d46cf1e631ee1c211a41004c1
   Storage Items 1
 Storage Deposit 999500000
 Source Language ink!

The downside of implementing this change is that it results in the need to download the WebAssembly (Wasm) code from the blockchain for every "info" call.

Checklist before requesting a review

My code follows the style guidelines of this project
I have added an entry to CHANGELOG.md
I have commented my code, particularly in hard-to-understand areas
I have added tests that prove my fix is effective or that my feature works
Any dependent changes have been merged and published in downstream modules

SkymanOne · 2023-09-12T15:19:54Z

The downside of implementing this change is that it results in the need to download the WebAssembly (Wasm) code from the blockchain for every "info" call.

Perhaps you can cache it?

smiasojed · 2023-09-12T15:37:41Z

I am not sure if it is real problem the issue could be visible when you iterate over all contracts addresses on chain to call info on them. In this case having cache<hash, wasm> could improve the performance assuming that the same contract is instantiated many times.

crates/analyze/Cargo.toml

ascjones · 2023-09-13T16:30:30Z

crates/analyze/src/lib.rs

+    if import_section_first != "memory"
+        && start_section.is_none()
+        && custom_sections.peek().is_none()


I'm not 100% convinced by this heuristic, I know it is copied from that python script.

It is because it is identifying the language based on the combination of a lack of things, which has the potential for false positives.

I would prefer to match on the presence of something, where we can be reasonably sure that it is an ink contract. We could add a custom section like the other languages (although that excludes contracts built with older versions). Alternatively we could identify the signature of a commonly used function somehow? e.g. a quick glance at a few contracts I can spot something that similar to:

incrementer.wat

(func (;8;) (type 5) (param i32) (local i32 i32 i32 i32) global.get 0 i32.const 16 i32.sub local.tee 1 global.set 0 local.get 1 i64.const 16384 i64.store offset=4 align=4 local.get 1 i32.const 65536 i32.store local.get 1 i32.const 0 call 9 block ;; label = @1

flipper.wat

(func (;11;) (type 6) (param i32) (local i32 i32 i32 i32) global.get 0 i32.const 32 i32.sub local.tee 1 global.set 0 local.get 1 i64.const 16384 i64.store offset=20 align=4 local.get 1 i32.const 65536 i32.store offset=16 local.get 1 i32.const 0 i32.store offset=12 local.get 1 i32.const 16 i32.add local.get 1 i32.const 12 i32.add i32.const 4 call 6 block ;; label = @1

Although not sure which function that corresponds to, but maybe there is another ink core library function we can find which is guaranteed to be included in the generated Wasm.

Anyway I would prefer to be more strict and miss some contracts that are written in ink rather than falsely categorising some contracts as having been written in ink.

I'm not a fan of this heuristic too. I only included it because the task was defined such way.
I can take a look to see if it could be done in a better way.

I think that basing on function presence can be risky, because inlining optimization can affect our logic. This function, which you are referring to, it is the deploy function. The advantage is that it will not be inlined, but its type is the same for Solang contracts.

For now I added check for the ink! function: pub fn deny_payment<E>() -> Result<(), DispatchError>
From the tests, it appears that its presence does not depend on the optimization type (size/performance) or its level, despite being defined with an inline attribute.
Stats from rococo wss://rococo-contracts-rpc.polkadot.io

total: 2778 ink!: 2643 Ask: 4 Solang: 22 Unknown: 109

ascjones

I think this is the right direction. We can consider adding a very small custom section to the Wasm for future ink versions, except obviously that will appear in every contract so that is the cost.

ascjones · 2023-10-19T10:03:37Z

crates/analyze/src/lib.rs

+    if start_section.is_none()
+        && (is_ink_function_present(&module) || has_function_name(&module, "ink_env"))
+    {
+        return Ok(Language::Ink)
+    } else if start_section.is_none() && has_custom_section(&module, "producers") {
+        return Ok(Language::Solidity)
+    } else if start_section.is_some() && has_custom_section(&module, "sourceMappingURL") {
+        return Ok(Language::AssemblyScript)
+    }


If we are reasonably certain that ink contracts will not have the custom sections of the solidity and ask, then we can change the order of this so that the ink if branch goes last.

This would reduce the possibility of a false positive ink identification, since it is still be possible for another type of contract to have a function matching the signature of deny_payment or transferred_value which has a call to value_transferred

Good point, I will change the order.

smiasojed · 2023-10-19T14:01:31Z

I think this is the right direction. We can consider adding a very small custom section to the Wasm for future ink versions, except obviously that will appear in every contract so that is the cost.

I can add an Ink custom section when the contract is built using the cargo-contract tool. A drawback of this solution is that if someone builds an Ink! contract without using the cargo-contract tool, the section will be missing.

ascjones

LGTM! I think @cmichi should also have a quick look since he originally specified the issue in #784.

smiasojed requested review from cmichi, ascjones and SkymanOne as code owners September 12, 2023 14:41

smiasojed changed the title ~~Sm/contract origin~~ Add heuristic to determine contract origin from Wasm blob Sep 12, 2023

Add determine contract language support

8898876

smiasojed force-pushed the sm/contract-origin branch from cdc0bc8 to 8898876 Compare September 12, 2023 15:28

Updated pull request desctiption in changelog

79c3d4f

ascjones reviewed Sep 13, 2023

View reviewed changes

smiasojed added 7 commits September 13, 2023 22:40

sign_ext feature added to parity_wasm in analyze crate

7348c0a

Merge remote-tracking branch 'origin/master' into sm/contract-origin

9c18a1d

Add function type check for ink

054cf02

code refactored

5ce7201

Merge remote-tracking branch 'origin/master' into sm/contract-origin

34a5272

Code cleanup

476e9b9

Fmt fix

20e047a

ascjones reviewed Oct 19, 2023

View reviewed changes

smiasojed added 2 commits October 20, 2023 09:35

Merge remote-tracking branch 'origin/master' into sm/contract-origin

bbd454d

Reorder if statement in analyze crate

2199aa7

ascjones approved these changes Oct 20, 2023

View reviewed changes

ascjones merged commit c2b550b into master Oct 23, 2023
11 checks passed

ascjones deleted the sm/contract-origin branch October 23, 2023 09:34

smiasojed mentioned this pull request Nov 30, 2023

Release v4.0.0-rc #1415

Merged

smiasojed mentioned this pull request Mar 4, 2024

Release v4.0.0 #1518

Merged

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Add heuristic to determine contract origin from Wasm blob #1329

Add heuristic to determine contract origin from Wasm blob #1329

smiasojed commented Sep 12, 2023 •

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Add heuristic to determine contract origin from Wasm blob #1329

Add heuristic to determine contract origin from Wasm blob #1329

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smiasojed commented Sep 12, 2023 • edited Loading

Summary

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Checklist before requesting a review

SkymanOne commented Sep 12, 2023

smiasojed commented Sep 12, 2023

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