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

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Message-ID: <aO6EyUVO9EOYfzV4@stanley.mountain>
Date: Tue, 14 Oct 2025 20:13:45 +0300
From: Dan Carpenter <dan.carpenter@...aro.org>
To: Vivek BalachandharTN <vivek.balachandhar@...il.com>
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()

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