linux-kernel - Re: [PATCH] net: ipconfig: replace strncpy with strscpy

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Message-ID: <1168af15-14dd-4eef-b1d7-c04de4781ea7@amd.com>
Date: Tue, 8 Apr 2025 14:44:42 -0700
From: "Nelson, Shannon" <shannon.nelson@....com>
To: Pranav Tyagi <pranav.tyagi03@...il.com>, davem@...emloft.net,
 dsahern@...nel.org, edumazet@...gle.com, kuba@...nel.org, pabeni@...hat.com,
 horms@...nel.org, skhan@...uxfoundation.org, netdev@...r.kernel.org,
 linux-kernel@...r.kernel.org, linux-kernel-mentees@...ts.linux.dev
Subject: Re: [PATCH] net: ipconfig: replace strncpy with strscpy_pad

On 4/8/2025 11:57 AM, Pranav Tyagi wrote:
> 
> Replace the deprecated strncpy() function with strscpy_pad() as the
> destination buffer is NUL-terminated and requires
> trailing NUL-padding
> 
> Signed-off-by: Pranav Tyagi <pranav.tyagi03@...il.com>

There should be a Fixes tag here, and usually we put the 'net' tree 
indicator inside the tag, like this: [PATCH net]


> ---
>   net/ipv4/ipconfig.c | 2 +-
>   1 file changed, 1 insertion(+), 1 deletion(-)
> 
> diff --git a/net/ipv4/ipconfig.c b/net/ipv4/ipconfig.c
> index c56b6fe6f0d7..7c238d19328f 100644
> --- a/net/ipv4/ipconfig.c
> +++ b/net/ipv4/ipconfig.c
> @@ -1690,7 +1690,7 @@ static int __init ic_proto_name(char *name)
>                          *v = 0;
>                          if (kstrtou8(client_id, 0, dhcp_client_identifier))
>                                  pr_debug("DHCP: Invalid client identifier type\n");
> -                       strncpy(dhcp_client_identifier + 1, v + 1, 251);
> +                       strscpy_pad(dhcp_client_identifier + 1, v + 1, 251);

The strncpy() action, as well as the memcpy() into 
dhcp_client_identifier elsewhere, are not padding to the end, so I think 
this only needs to be null-terminated, not fully padded.  If full 
padding is needed, please let us know why.

sln

>                          *v = ',';
>                  }
>                  return 1;
> --
> 2.49.0
> 
>