linux-kernel - Re: [PATCH] staging: greybus: documentation: replace strncpy() with strscpy

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Message-ID: <451b7aaf-86d0-4a0d-9578-b76c3a7886d5@gmail.com>
Date: Tue, 14 Oct 2025 19:53:05 -0400
From: Vivek BalachandharTN <vivek.balachandhar@...il.com>
To: Dan Carpenter <dan.carpenter@...aro.org>
Cc: gregkh@...uxfoundation.org, johan@...nel.org, elder@...nel.org,
 schopin@...ntu.com, me@...y.me, greybus-dev@...ts.linaro.org,
 linux-staging@...ts.linux.dev, linux-kernel@...r.kernel.org
Subject: Re: [PATCH] staging: greybus: documentation: replace strncpy() with
 strscpy_pad()

Hi Dan,

Thanks for clarifying. That makes sense — since the struct starts
zeroed and the last byte remains untouched, the current code is
already safe. I’ll drop this patch.

Appreciate the quick guidance.

Best
Vivek

On 2025-10-14 1:13 p.m., Dan Carpenter wrote:
> On Tue, Oct 14, 2025 at 12:10:50PM -0400, Vivek BalachandharTN wrote:
>> Hi Dan,
>>
>> Thanks again—confirmed the structs are zero-initialized before the copy.
>>
>> Would a minimal fix that guarantees NUL-termination be acceptable, e.g.:
>>
>> strncpy((char *)&intf_load.firmware_tag, firmware_tag,
>>          GB_FIRMWARE_U_TAG_MAX_SIZE - 1);
>> ((char *)&intf_load.firmware_tag)[GB_FIRMWARE_U_TAG_MAX_SIZE - 1] = '\0';
>>
>> I can respin as v2 with the same change applied to the other two
>> firmware_tag
>> fields.
> Sorry, I should have explained this at the start...  The struct is
> initialized to zero.  The strncpy() copies at most
> "GB_FIRMWARE_U_TAG_MAX_SIZE - 1" characters, meaning we never copy
> anything to the last character which stays as zero.
>
> regards,
> dan carpenter
>