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From: Dan Carpenter <error27@gmail.com>
To: Andy Shevchenko <andriy.shevchenko@intel.com>
Cc: Shyam Sunder Reddy Padira <shyamsunderreddypadira@gmail.com>,
	gregkh@linuxfoundation.org, ethantidmore06@gmail.com,
	nayana.mariyappa@gmail.com, s9430939@naver.com, kees@kernel.org,
	linux-staging@lists.linux.dev, linux-kernel@vger.kernel.org
Subject: Re: [PATCH v3] staging: rtl8723bs: os_dep: avoid NULL pointer dereference in rtw_cbuf_alloc
Date: Tue, 14 Apr 2026 12:09:38 +0300	[thread overview]
Message-ID: <ad4EUpIInGHin71O@stanley.mountain> (raw)
In-Reply-To: <ad3-Yhh2kPsbYILC@ashevche-desk.local>

On Tue, Apr 14, 2026 at 11:44:18AM +0300, Andy Shevchenko wrote:
> On Tue, Apr 14, 2026 at 11:33:22AM +0300, Dan Carpenter wrote:
> > Really _obj() can't be ZERO_SIZE_PTR either, or if they are then it's
> > very difficult to dereference them since they don't have any struct
> > members.
> > 
> > The main way that ZERO_SIZE_PTR bugs show up is with strings and NUL
> > terminators.
> 
> Wouldn't it be the problem for
> 
> struct foo {
> 	u32 baz[];
> };

There isn't really any difference between doing an out of bounds access
on an array with zero elements vs 10 elements.  That's the beauty of
the ZERO_SIZE_PTR is that it lets you treat zero as just another number
of elements.  But zero sizes can cause problems for code which does
things like "size - 1" but because of signedness that's ULONG_MAX.

regards,
dan carpenter

      parent reply	other threads:[~2026-04-14  9:29 UTC|newest]

Thread overview: 16+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2026-04-13 18:08 [PATCH] staging: rtl8723bs: os_dep: avoid NULL pointer derefernece in rtw_cbuf_alloc Shyam Sunder Reddy Padira
2026-04-13 20:51 ` Ethan Tidmore
2026-04-13 22:44   ` [PATCH v2] staging: rtl8723bs: os_dep: avoid NULL pointer dereference " Shyam Sunder Reddy Padira
     [not found]     ` <CALx+fbZ_K3C2sTWY_HigceJcp414OEhyEQLGTDEfNnU2q_zKiA@mail.gmail.com>
2026-04-13 23:57       ` Shyam Sunder Reddy Padira
2026-04-14  5:59     ` Dan Carpenter
2026-04-14  7:42       ` Andy Shevchenko
2026-04-14  7:13     ` [PATCH v3] " Shyam Sunder Reddy Padira
2026-04-14  7:19       ` Dan Carpenter
2026-04-14  7:46       ` Andy Shevchenko
2026-04-14  7:55         ` Dan Carpenter
2026-04-14  8:00           ` Dan Carpenter
2026-04-14  8:20             ` Andy Shevchenko
2026-04-14  8:33               ` Dan Carpenter
2026-04-14  8:44                 ` Andy Shevchenko
2026-04-14  8:47                   ` Andy Shevchenko
2026-04-14  9:09                   ` Dan Carpenter [this message]

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