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From: Kees Cook <kees@kernel.org>
To: Thorsten Blum <thorsten.blum@linux.dev>
Cc: Allison Henderson <allison.henderson@oracle.com>,
	"David S. Miller" <davem@davemloft.net>,
	Eric Dumazet <edumazet@google.com>,
	Jakub Kicinski <kuba@kernel.org>, Paolo Abeni <pabeni@redhat.com>,
	Simon Horman <horms@kernel.org>,
	linux-hardening@vger.kernel.org, netdev@vger.kernel.org,
	linux-rdma@vger.kernel.org, rds-devel@oss.oracle.com,
	linux-kernel@vger.kernel.org
Subject: Re: [PATCH net-next] net/rds: Replace deprecated strncpy() with strscpy_pad()
Date: Thu, 20 Feb 2025 00:54:38 -0800	[thread overview]
Message-ID: <CCF15545-8AF8-40A8-917C-E44B6373D9AE@kernel.org> (raw)
In-Reply-To: <08A0C3AE-A255-467F-A007-5584E8E44517@linux.dev>



On February 19, 2025 11:04:18 PM PST, Thorsten Blum <thorsten.blum@linux.dev> wrote:
>On 20. Feb 2025, at 03:57, Kees Cook wrote:
>> On Wed, Feb 19, 2025 at 11:47:31PM +0100, Thorsten Blum wrote:
>>> strncpy() is deprecated for NUL-terminated destination buffers. Use
>>> strscpy_pad() instead and remove the manual NUL-termination.
>> 
>> When doing these conversions, please describe two aspects of
>> conversions:
>> 
>> - Why is it safe to be NUL terminated
>> - Why is it safe to be/not-be NUL-padded
>> 
>> In this case, the latter needs examination. Looking at how ctr is used,
>> it is memcpy()ed later, which means this string MUST be NUL padded or it
>> will leak stack memory contents.
>> 
>> So, please use strscpy_pad() here. :)
>
>I am using strscpy_pad() here already because of the NUL-padding.
>
>Did you just miss that?

Well that's embarrassing. Yes, I must need stronger glasses. *sigh* Apologies for the noise!

Reviewed-by: Kees Cook <kees@kernel.org>


-- 
Kees Cook

  reply	other threads:[~2025-02-20  8:54 UTC|newest]

Thread overview: 7+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2025-02-19 22:47 [PATCH net-next] net/rds: Replace deprecated strncpy() with strscpy_pad() Thorsten Blum
2025-02-20  2:57 ` Kees Cook
2025-02-20  7:04   ` Thorsten Blum
2025-02-20  8:54     ` Kees Cook [this message]
2025-02-20 18:07 ` Allison Henderson
2025-02-20 18:49   ` Allison Henderson
2025-02-22  0:10 ` patchwork-bot+netdevbpf

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