Re: [PATCH v3 2/4] selinux: replace some BUG_ON()s with a WARN_ON()

[Stephen Smalley <sds@xxxxxxxxxxxxx>]

On 1/25/19 5:06 AM, Ondrej Mosnacek wrote:
> We don't need to crash the machine in these cases. Let's just detect the
> buggy state early and error out with a warning.
>
> Signed-off-by: Ondrej Mosnacek <omosnace@xxxxxxxxxx>

Reviewed-by: Stephen Smalley <sds@xxxxxxxxxxxxx>

> ---
>   security/selinux/avc.c | 5 +++--
>   1 file changed, 3 insertions(+), 2 deletions(-)
>
> diff --git a/security/selinux/avc.c b/security/selinux/avc.c
> index 502162eeb3a0..5ebad47391c9 100644
> --- a/security/selinux/avc.c
> +++ b/security/selinux/avc.c
> @@ -678,7 +678,6 @@ static void avc_audit_pre_callback(struct audit_buffer *ab, void *a)
>   		return;
>   	}
>   
> -	BUG_ON(!sad->tclass || sad->tclass >= ARRAY_SIZE(secclass_map));
>   	perms = secclass_map[sad->tclass-1].perms;
>   
>   	audit_log_string(ab, " {");
> @@ -731,7 +730,6 @@ static void avc_audit_post_callback(struct audit_buffer *ab, void *a)
>   		kfree(scontext);
>   	}
>   
> -	BUG_ON(!sad->tclass || sad->tclass >= ARRAY_SIZE(secclass_map));
>   	audit_log_format(ab, " tclass=%s", secclass_map[sad->tclass-1].name);
>   
>   	if (sad->denied)
> @@ -748,6 +746,9 @@ noinline int slow_avc_audit(struct selinux_state *state,
>   	struct common_audit_data stack_data;
>   	struct selinux_audit_data sad;
>   
> +	if (WARN_ON(!tclass || tclass >= ARRAY_SIZE(secclass_map)))
> +		return -EINVAL;
> +
>   	if (!a) {
>   		a = &stack_data;
>   		a->type = LSM_AUDIT_DATA_NONE;