Re: [PATCH net-next] net/devlink: Use strscpy() to copy strings into arrays

[Paolo Abeni]

On 6/8/26 11:54 AM, david.laight.linux@xxxxxxxxx wrote:
> From: David Laight <david.laight.linux@xxxxxxxxx>
> 
> Replacing strcpy() with strscpy() ensures that overflow of the target
> buffer cannot happen.
> 
> Signed-off-by: David Laight <david.laight.linux@xxxxxxxxx>
> ---
> This is one of a group of patches that remove potentially unbounded
> strcpy() calls.
> 
> They are mostly replaced by strscpy() or, when strlen() has just been
> called, with memcpy() (usually including the '\0').
> 
> Calls with copy string literals into arrays are left unchanged.
> They are safe and easily detected as such.
> 
> The changes were made by getting the compiler to detect the calls and
> then fixing the code by hand.
> 
> Note that all the changes are only compile tested.
> 
> Some Makefiles were changed to allow files to contain strcpy().
> As well as 'difficult to fix' files, this included 'show' functions
> as they really need to use sysfs_emit() or seq_printf().
> 
> All the patches are being sent individually to avoid very long cc lists.
> Apologies for the terse commit messages and likely unexpected tags.
> (There are about 100 patches in total.)
> 
>  net/devlink/port.c | 2 +-
>  1 file changed, 1 insertion(+), 1 deletion(-)
> 
> diff --git a/net/devlink/port.c b/net/devlink/port.c
> index 485029d43428..108926d3f899 100644
> --- a/net/devlink/port.c
> +++ b/net/devlink/port.c
> @@ -1222,7 +1222,7 @@ static void __devlink_port_type_set(struct devlink_port *devlink_port,
>  			devlink_port->type_eth.ifindex = netdev->ifindex;
>  			BUILD_BUG_ON(sizeof(devlink_port->type_eth.ifname) !=
>  				     sizeof(netdev->name));
> -			strcpy(devlink_port->type_eth.ifname, netdev->name);
> +			strscpy(devlink_port->type_eth.ifname, netdev->name);

Given the above BUILD_BUG, I don't see how this change can help?!?

Generally speaking, I suggest restricting this kind of tool-assisted
changes to real problems (if any).

Thanks,

Paolo