linux-kernel - Re: [PATCH] resource: use kstrdup_const to prevent wild pointer issues

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Message-ID: <87seq2dlhd.fsf@DESKTOP-5N7EMDA>
Date: Thu, 02 Jan 2025 09:59:26 +0800
From: "Huang, Ying" <ying.huang@...ux.alibaba.com>
To: kingdix10@...com
Cc: akpm@...ux-foundation.org,  andriy.shevchenko@...ux.intel.com,
  ilpo.jarvinen@...ux.intel.com,  bhelgaas@...gle.com,
  mika.westerberg@...ux.intel.com,  huang.ying.caritas@...il.com,
  jhubbard@...dia.com,  peterz@...radead.org,  linux-kernel@...r.kernel.org
Subject: Re: [PATCH] resource: use kstrdup_const to prevent wild pointer issues

kingdix10@...com writes:

> From: King Dix <kingdix10@...com>
>
> When a stack string variable is passed during the request resource
> operation, it causes an oops problem when executing cat /proc/iomem.
>
> In the original code, in functions like __request_region_locked, the name
> member of the resource structure was directly assigned the stack string
> pointer without proper memory management.
>
> This fix changes the assignment of res->name to use kstrdup_const for
> string copying, ensuring the correct storage and release of the string
> and thus avoiding potential memory errors and oops issues.
>
> Signed-off-by: King Dix <kingdix10@...com>

In general, I think that it's good to improve the resource requesting
API.  However, it's not good to use so many GFP_ATOMIC too.  Why do you
need to call resource requesting API with stack variable?  If it's just
some programming bugs, we should add more checks instead of hiding the
bugs.  For example, if we only allows kernel rodata and slab memory to be
used in resource requesting.  We can add a VM_WARN_ON() to check that.

[snip]

---
Best Regards,
Huang, Ying