Re: [RFC PATCH ghak59 V1 3/6] audit: exclude user records from syscall context

[Paul Moore]

On Thu, Jun 14, 2018 at 4:23 PM Richard Guy Briggs <rgb@xxxxxxxxxx> wrote:
> Since the function audit_log_common_recv_msg() is shared by a number of
> AUDIT_CONFIG_CHANGE and the entire range of AUDIT_USER_* record types,
> and since the AUDIT_CONFIG_CHANGE message type has been converted to a
> syscall accompanied record type, special-case the AUDIT_USER_* range of
> messages so they remain standalone records.
>
> See: https://github.com/linux-audit/audit-kernel/issues/59
> Signed-off-by: Richard Guy Briggs <rgb@xxxxxxxxxx>
> ---
>  kernel/audit.c | 12 +++++++++---
>  1 file changed, 9 insertions(+), 3 deletions(-)

I think this is fine, but see my previous comment about combining 2/6
and 3/6 as a safety measure.

> diff --git a/kernel/audit.c b/kernel/audit.c
> index e469234..c8c2efc 100644
> --- a/kernel/audit.c
> +++ b/kernel/audit.c
> @@ -1057,7 +1057,8 @@ static int audit_netlink_ok(struct sk_buff *skb, u16 msg_type)
>         return err;
>  }
>
> -static void audit_log_common_recv_msg(struct audit_buffer **ab, u16 msg_type)
> +static void __audit_log_common_recv_msg(struct audit_context *context,
> +                                       struct audit_buffer **ab, u16 msg_type)
>  {
>         uid_t uid = from_kuid(&init_user_ns, current_uid());
>         pid_t pid = task_tgid_nr(current);
> @@ -1067,7 +1068,7 @@ static void audit_log_common_recv_msg(struct audit_buffer **ab, u16 msg_type)
>                 return;
>         }
>
> -       *ab = audit_log_start(audit_context(), GFP_KERNEL, msg_type);
> +       *ab = audit_log_start(context, GFP_KERNEL, msg_type);
>         if (unlikely(!*ab))
>                 return;
>         audit_log_format(*ab, "pid=%d uid=%u", pid, uid);
> @@ -1075,6 +1076,11 @@ static void audit_log_common_recv_msg(struct audit_buffer **ab, u16 msg_type)
>         audit_log_task_context(*ab);
>  }
>
> +static inline void audit_log_common_recv_msg(struct audit_buffer **ab, u16 msg_type)
> +{
> +       __audit_log_common_recv_msg(audit_context(), ab, msg_type);
> +}
> +
>  int is_audit_feature_set(int i)
>  {
>         return af.features & AUDIT_FEATURE_TO_MASK(i);
> @@ -1341,7 +1347,7 @@ static int audit_receive_msg(struct sk_buff *skb, struct nlmsghdr *nlh)
>                                 if (err)
>                                         break;
>                         }
> -                       audit_log_common_recv_msg(&ab, msg_type);
> +                       __audit_log_common_recv_msg(NULL, &ab, msg_type);
>                         if (msg_type != AUDIT_USER_TTY)
>                                 audit_log_format(ab, " msg='%.*s'",
>                                                  AUDIT_MESSAGE_TEXT_MAX,
> --
> 1.8.3.1
>


-- 
paul moore
www.paul-moore.com