Re: [PATCH V34 29/29] lockdown: Print current->comm in restriction messages

Kees Cook
2019-06-23T00:25:33Z

On Fri, Jun 21, 2019 at 05:03:58PM -0700, Matthew Garrett wrote:
> Print the content of current->comm in messages generated by lockdown to
> indicate a restriction that was hit. This makes it a bit easier to find
> out what caused the message.
>
> The message now patterned something like:
>
> Lockdown: <comm>: <what> is restricted; see man kernel_lockdown.7
>
> Signed-off-by: David Howells <dhowells@redhat.com>
> Signed-off-by: Matthew Garrett <mjg59@google.com>
> ---
> security/lockdown/lockdown.c | 4 ++--
> 1 file changed, 2 insertions(+), 2 deletions(-)
>
> diff --git a/security/lockdown/lockdown.c b/security/lockdown/lockdown.c
> index 98f9ee0026d5..9ca6f442fbc7 100644
> --- a/security/lockdown/lockdown.c
> +++ b/security/lockdown/lockdown.c
> @@ -83,8 +83,8 @@ static int lockdown_is_locked_down(enum lockdown_reason what)
> {
> if ((kernel_locked_down >= what)) {

To satisfy my paranoia, can you just add here:

if (WARN(what > LOCKDOWN_..._MAX))
return -EPERM;

With that:

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

-Kees

> if (lockdown_reasons[what])
> - pr_notice("Lockdown: %s is restricted; see man kernel_lockdown.7\n",
> - lockdown_reasons[what]);
> + pr_notice("Lockdown: %s: %s is restricted; see man kernel_lockdown.7\n",
> + current->comm, lockdown_reasons[what]);
> return -EPERM;
> }
>
> --
> 2.22.0.410.gd8fdbe21b5-goog
>

--
Kees Cook