Re: [PATCH 2/2] lockd: change the proc_handler for nsm_use_hostnames

[Kees Cook <keescook@chromium.org>]

On Tue, Aug 03, 2021 at 12:59:37PM +0200, Thomas Huth wrote:
> From: Jia He <hejianet@gmail.com>
> 
> nsm_use_hostnames is a module parameter and it will be exported to sysctl
> procfs. This is to let user sometimes change it from userspace. But the
> minimal unit for sysctl procfs read/write it sizeof(int).
> In big endian system, the converting from/to  bool to/from int will cause
> error for proc items.
> 
> This patch use a new proc_handler proc_dobool to fix it.
> 
> Signed-off-by: Jia He <hejianet@gmail.com>
> Reviewed-by: Pan Xinhui <xinhui.pan@linux.vnet.ibm.com>
> [thuth: Fix typo in commit message]
> Signed-off-by: Thomas Huth <thuth@redhat.com>
> ---
>  fs/lockd/svc.c | 2 +-
>  1 file changed, 1 insertion(+), 1 deletion(-)
> 
> diff --git a/fs/lockd/svc.c b/fs/lockd/svc.c
> index 2de048f80eb8..0ab9756ed235 100644
> --- a/fs/lockd/svc.c
> +++ b/fs/lockd/svc.c
> @@ -584,7 +584,7 @@ static struct ctl_table nlm_sysctls[] = {
>  		.data		= &nsm_use_hostnames,
>  		.maxlen		= sizeof(int),

For robustness, maybe this should be:

		.maxlen		= sizeof(nsm_use_hostnames),

>  		.mode		= 0644,
> -		.proc_handler	= proc_dointvec,
> +		.proc_handler	= proc_dobool,
>  	},
>  	{
>  		.procname	= "nsm_local_state",
> -- 
> 2.27.0
> 

Reviewed-by: Kees Cook <keescook@chromium.org>

Also, I wonder what other BE-corrupted bools are out there?

-- 
Kees Cook