Re: [RFC PATCH ghak86 V1] audit: use audit_enabled as a boolean where convenient

[Paul Moore]

On Thu, May 31, 2018 at 11:13 AM, Richard Guy Briggs <rgb@xxxxxxxxxx> wrote:
> Most uses of audit_enabled don't care about the distinction between
> AUDIT_ON and AUDIT_LOCKED, so using audit_enabled as a boolean makes
> more sense and is easier to read. Most uses of audit_enabled treat it as
> a boolean, so switch the remaining AUDIT_OFF usage to simply use
> audit_enabled as a boolean where applicable.
>
> See: https://github.com/linux-audit/audit-kernel/issues/86
>
> Signed-off-by: Richard Guy Briggs <rgb@xxxxxxxxxx>
> ---
>  drivers/tty/tty_audit.c      | 2 +-
>  include/net/xfrm.h           | 2 +-
>  kernel/audit.c               | 8 ++++----
>  net/netfilter/xt_AUDIT.c     | 2 +-
>  net/netlabel/netlabel_user.c | 2 +-
>  5 files changed, 8 insertions(+), 8 deletions(-)

I'm not sure I like this idea.  Yes, technically this change is
functionally equivalent but I worry that this will increase the chance
that non-audit folks will mistake audit_enabled as a true/false value
when it is not.  It might work now, but I worry about some subtle
problem in the future.

If you are bothered by the comparison to 0 (magic numbers), you could
move the AUDIT_OFF/AUDIT_ON/AUDIT_LOCKED definitions into
include/linux/audit.h and convert the "audit_enabled == 0" to
"audit_enabled == AUDIT_OFF".

> diff --git a/drivers/tty/tty_audit.c b/drivers/tty/tty_audit.c
> index e30aa6b..1e48051 100644
> --- a/drivers/tty/tty_audit.c
> +++ b/drivers/tty/tty_audit.c
> @@ -92,7 +92,7 @@ static void tty_audit_buf_push(struct tty_audit_buf *buf)
>  {
>         if (buf->valid == 0)
>                 return;
> -       if (audit_enabled == 0) {
> +       if (!audit_enabled) {
>                 buf->valid = 0;
>                 return;
>         }
> diff --git a/include/net/xfrm.h b/include/net/xfrm.h
> index 7f2e31a..380542b 100644
> --- a/include/net/xfrm.h
> +++ b/include/net/xfrm.h
> @@ -734,7 +734,7 @@ static inline struct audit_buffer *xfrm_audit_start(const char *op)
>  {
>         struct audit_buffer *audit_buf = NULL;
>
> -       if (audit_enabled == 0)
> +       if (!audit_enabled)
>                 return NULL;
>         audit_buf = audit_log_start(audit_context(), GFP_ATOMIC,
>                                     AUDIT_MAC_IPSEC_EVENT);
> diff --git a/kernel/audit.c b/kernel/audit.c
> index e7478cb..3a18e59 100644
> --- a/kernel/audit.c
> +++ b/kernel/audit.c
> @@ -424,7 +424,7 @@ static int audit_do_config_change(char *function_name, u32 *to_change, u32 new)
>         else
>                 allow_changes = 1;
>
> -       if (audit_enabled != AUDIT_OFF) {
> +       if (audit_enabled) {
>                 rc = audit_log_config_change(function_name, new, old, allow_changes);
>                 if (rc)
>                         allow_changes = 0;
> @@ -1097,7 +1097,7 @@ static void audit_log_feature_change(int which, u32 old_feature, u32 new_feature
>  {
>         struct audit_buffer *ab;
>
> -       if (audit_enabled == AUDIT_OFF)
> +       if (!audit_enabled)
>                 return;
>         ab = audit_log_start(audit_context(), GFP_KERNEL, AUDIT_FEATURE_CHANGE);
>         if (!ab)
> @@ -1270,7 +1270,7 @@ static int audit_receive_msg(struct sk_buff *skb, struct nlmsghdr *nlh)
>                                 err = auditd_set(req_pid,
>                                                  NETLINK_CB(skb).portid,
>                                                  sock_net(NETLINK_CB(skb).sk));
> -                               if (audit_enabled != AUDIT_OFF)
> +                               if (audit_enabled)
>                                         audit_log_config_change("audit_pid",
>                                                                 new_pid,
>                                                                 auditd_pid,
> @@ -1281,7 +1281,7 @@ static int audit_receive_msg(struct sk_buff *skb, struct nlmsghdr *nlh)
>                                 /* try to process any backlog */
>                                 wake_up_interruptible(&kauditd_wait);
>                         } else {
> -                               if (audit_enabled != AUDIT_OFF)
> +                               if (audit_enabled)
>                                         audit_log_config_change("audit_pid",
>                                                                 new_pid,
>                                                                 auditd_pid, 1);
> diff --git a/net/netfilter/xt_AUDIT.c b/net/netfilter/xt_AUDIT.c
> index f368ee6..3921553 100644
> --- a/net/netfilter/xt_AUDIT.c
> +++ b/net/netfilter/xt_AUDIT.c
> @@ -72,7 +72,7 @@ static bool audit_ip6(struct audit_buffer *ab, struct sk_buff *skb)
>         struct audit_buffer *ab;
>         int fam = -1;
>
> -       if (audit_enabled == 0)
> +       if (!audit_enabled)
>                 goto errout;
>         ab = audit_log_start(NULL, GFP_ATOMIC, AUDIT_NETFILTER_PKT);
>         if (ab == NULL)
> diff --git a/net/netlabel/netlabel_user.c b/net/netlabel/netlabel_user.c
> index 2f328af..e68fa9d 100644
> --- a/net/netlabel/netlabel_user.c
> +++ b/net/netlabel/netlabel_user.c
> @@ -101,7 +101,7 @@ struct audit_buffer *netlbl_audit_start_common(int type,
>         char *secctx;
>         u32 secctx_len;
>
> -       if (audit_enabled == 0)
> +       if (!audit_enabled)
>                 return NULL;
>
>         audit_buf = audit_log_start(audit_context(), GFP_ATOMIC, type);
> --
> 1.8.3.1
>



-- 
paul moore
www.paul-moore.com