CVE-2022-0156 vim is vulnerable to Use After Free

CVE-2022-0156 vim is vulnerable to Use After Free

The condition where a program crashes, but before the program ends. The problem arises from the use of dynamically allocated memory. When the program crashes, this memory is no longer valid and must be freed. However, the memory is not immediately freed because it is controlled by the vim process itself. If a user modifies the memory, then the vim process can crash, and the memory will never be freed. This can lead to a memory leak that will continue to consume more and more memory as time passes. A user can check for memory leaks by using the Vim debug commands. One command that can be used is :debug leak.

How to detect memory leaks in Vim

Memory leaks can arise when a program has incorrectly allocated memory or if a program crashes, but before the program ends. To detect memory leaks in Vim, you could use the command :debug leak. This will show an error if it detects a memory leak. One way to fix this is to set the help-level of the list to 0 and then use :help help-level.

VIM Debug Commands

By using Vim's debug commands, you can check for memory leaks within vim. One command that can be used is :debug leak. This command performs a test that determines if memory is being leaked. This command prints the number of code bytes that are currently in use and the total amount of bytes consumed by all the process. If this number exceeds the ceiling value, then it is possible that the vim process has a memory leak.
If you want to find out if your vim process has a memory leak or not, then use this command:
:echo ~x/%x/%x-\zs\+

Vulnerability

Vulnerabilities can arise from a variety of sources, but they all share one commonality: they cause problems. Common examples of vulnerabilities include buffer overflow and insecure memory management errors. Buffer overflow vulnerabilities are caused when a program tries to store more information in an allocated buffer than is allowed by the size of the buffer. This can lead to problems, such as not being able to allocate enough memory required for the program to run. Insecure memory management errors are caused when the program does not properly check if the pointer it references is valid before using it as a reference.
First, you should make sure that your vim uses secure memory management practices before anything else. If you're unsure about whether or not this is happening, run :set nocp and use :verbose setpos. You should see no messages if vim uses secure or non-secure memory management practices correctly.

References

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