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gfwilliams / tiny-js

Automatically exported from code.google.com/p/tiny-js
MIT License
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Null pointer dereference #37

Open bird8693 opened 4 years ago

bird8693 commented 4 years ago

Enviroment

operating system: ubuntu18.04
compile command: make
test command: ./run_tests  poc

poc:

https://drive.google.com/open?id=1SQYrTreCmgZdXTbM6dAvZfMQSG3WYnRV

vulnerability description:

It is a problem with CTinyJS :: expression. On the TinyJS.cpp + 1776 line, a null pointer reference is triggered, as shown in the figure: image

The reason for the vulnerability is that when a temporary assignment variable a is generated, it is not verified whether a is empty, and then a-> var refers to a, which causes the vulnerability.

PoC construction

During the variable declaration, write 0. image