Re: [PATCH v2] fs: lockd: avoid possible wrong NULL parameter

[Jeff Layton <jlayton@kernel.org>]

On Fri, 2023-08-04 at 09:26 +0800, Su Hui wrote:
> clang's static analysis warning: fs/lockd/mon.c: line 293, column 2:
> Null pointer passed as 2nd argument to memory copy function.
> 
> Assuming 'hostname' is NULL and calling 'nsm_create_handle()', this will
> pass NULL as 2nd argument to memory copy function 'memcpy()'. So return
> NULL if 'hostname' is invalid.
> 
> Fixes: 77a3ef33e2de ("NSM: More clean up of nsm_get_handle()")
> Signed-off-by: Su Hui <suhui@nfschina.com>
> ---
> v2:
>  - move NULL check to the callee "nsm_create_handle()"
>  fs/lockd/mon.c | 3 +++
>  1 file changed, 3 insertions(+)
> 
> diff --git a/fs/lockd/mon.c b/fs/lockd/mon.c
> index 1d9488cf0534..87a0f207df0b 100644
> --- a/fs/lockd/mon.c
> +++ b/fs/lockd/mon.c
> @@ -276,6 +276,9 @@ static struct nsm_handle *nsm_create_handle(const struct sockaddr *sap,
>  {
>  	struct nsm_handle *new;
>  
> +	if (!hostname)
> +		return NULL;
> +
>  	new = kzalloc(sizeof(*new) + hostname_len + 1, GFP_KERNEL);
>  	if (unlikely(new == NULL))
>  		return NULL;

Reviewed-by: Jeff Layton <jlayton@kernel.org>