linux-kernel - Re: [PATCH v2] net/ipv4/tcp_cong: Replace strncpy() with strscpy()

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Message-ID: <6d1a441d-31f9-4bc3-8856-be18620e4401@redhat.com>
Date: Tue, 16 Jul 2024 13:31:53 +0200
From: Paolo Abeni <pabeni@...hat.com>
To: Simon Horman <horms@...nel.org>, Kees Cook <kees@...nel.org>,
 Eric Dumazet <edumazet@...gle.com>
Cc: "David S. Miller" <davem@...emloft.net>, David Ahern
 <dsahern@...nel.org>, Jakub Kicinski <kuba@...nel.org>,
 netdev@...r.kernel.org, linux-kernel@...r.kernel.org,
 linux-hardening@...r.kernel.org
Subject: Re: [PATCH v2] net/ipv4/tcp_cong: Replace strncpy() with strscpy()

On 7/15/24 11:41, Simon Horman wrote:
> On Sat, Jul 13, 2024 at 09:11:15PM -0700, Kees Cook wrote:
>> Replace the deprecated[1] uses of strncpy() in tcp_ca_get_name_by_key()
>> and tcp_get_default_congestion_control(). The callers use the results as
>> standard C strings (via nla_put_string() and proc handlers respectively),
>> so trailing padding is not needed.
>>
>> Since passing the destination buffer arguments decays it to a pointer,
>> the size can't be trivially determined by the compiler. ca->name is
>> the same length in both cases, so strscpy() won't fail (when ca->name
>> is NUL-terminated). Include the length explicitly instead of using the
>> 2-argument strscpy().
>>
>> Link: https://github.com/KSPP/linux/issues/90 [1]
>> Signed-off-by: Kees Cook <kees@...nel.org>
> 
> nit: Looking at git history, the subject prefix should probably be 'tcp'.
>       And it would be best to explicitly target the patch against net-next.
> 
>       Subject: [PATCH net-next v2] tcp: ...
> 
> That notwithstanding, this looks good to me.
> 
> Reviewed-by: Simon Horman <horms@...nel.org>

@Eric: I can fix the prefix when applying the patch. Please LMK if you 
prefer otherwise.

Thanks,

Paolo