linux-hardening - Re: [PATCH] RFC v2 struct const ops pointers member hardening

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Date:   Fri, 30 Jul 2021 12:18:52 +0200
From:   "Enrico Weigelt, metux IT consult" <lkml@...ux.net>
To:     Wang Zi-cheng <wzc@...il.nju.edu.cn>, keescook@...omium.org,
        tycho@...ho.pizza, linux-hardening@...r.kernel.org
Subject: Re: [PATCH] RFC v2 struct const ops pointers member hardening

On 28.07.21 08:52, Wang Zi-cheng wrote:

Hi,

> 1. this is a useful hardening, my opinion was wrong in the previous patch,
> because the attacker may overwrite a struct with an "struct file*" pointer,
>   which point to a manufactured file struct with malicious f_op.
> Hardening operation pointers CAN help.
>> On the other side, kernel uses `kmem_cache_create` to alloc file/inode rather than `kmalloc`,
>> which makes it hard to exploit through heap overflow or UAF, so maybe this is not a "must" update.

note that there can be situations where a file_operations struct is
actually created at runtime. quite rare, but still possible.


--mtx

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Enrico Weigelt, metux IT consult
Free software and Linux embedded engineering
info@...ux.net -- +49-151-27565287