Re: [PATCH ghak25 v3 1/3] audit: tidy and extend netfilter_cfg x_tables and ebtables logging

[Paul Moore]

On Tue, Mar 17, 2020 at 5:31 PM Richard Guy Briggs <rgb@xxxxxxxxxx> wrote:
>
> NETFILTER_CFG record generation was inconsistent for x_tables and
> ebtables configuration changes.  The call was needlessly messy and there
> were supporting records missing at times while they were produced when
> not requested.  Simplify the logging call into a new audit_log_nfcfg
> call.  Honour the audit_enabled setting while more consistently
> recording information including supporting records by tidying up dummy
> checks.
>
> Add an op= field that indicates the operation being performed (register
> or replace).
>
> Here is the enhanced sample record:
>   type=NETFILTER_CFG msg=audit(1580905834.919:82970): table=filter family=2 entries=83 op=replace
>
> Generate audit NETFILTER_CFG records on ebtables table registration.
> Previously this was being done for x_tables registration and replacement
> operations and ebtables table replacement only.
>
> See: https://github.com/linux-audit/audit-kernel/issues/25
> See: https://github.com/linux-audit/audit-kernel/issues/35
> See: https://github.com/linux-audit/audit-kernel/issues/43
>
> Signed-off-by: Richard Guy Briggs <rgb@xxxxxxxxxx>
> ---
>  include/linux/audit.h           | 19 +++++++++++++++++++
>  kernel/auditsc.c                | 24 ++++++++++++++++++++++++
>  net/bridge/netfilter/ebtables.c | 12 ++++--------
>  net/netfilter/x_tables.c        | 12 +++---------
>  4 files changed, 50 insertions(+), 17 deletions(-)
>
> diff --git a/include/linux/audit.h b/include/linux/audit.h
> index f9ceae57ca8d..f4aed2b9be8d 100644
> --- a/include/linux/audit.h
> +++ b/include/linux/audit.h
> @@ -94,6 +94,11 @@ struct audit_ntp_data {
>  struct audit_ntp_data {};
>  #endif
>
> +enum audit_nfcfgop {
> +       AUDIT_XT_OP_REGISTER,
> +       AUDIT_XT_OP_REPLACE,
> +};
> +
>  extern int is_audit_feature_set(int which);
>
>  extern int __init audit_register_class(int class, unsigned *list);
> @@ -379,6 +384,8 @@ extern int __audit_log_bprm_fcaps(struct linux_binprm *bprm,
>  extern void __audit_fanotify(unsigned int response);
>  extern void __audit_tk_injoffset(struct timespec64 offset);
>  extern void __audit_ntp_log(const struct audit_ntp_data *ad);
> +extern void __audit_log_nfcfg(const char *name, u8 af, unsigned int nentries,
> +                             enum audit_nfcfgop op);
>
>  static inline void audit_ipc_obj(struct kern_ipc_perm *ipcp)
>  {
> @@ -514,6 +521,13 @@ static inline void audit_ntp_log(const struct audit_ntp_data *ad)
>                 __audit_ntp_log(ad);
>  }
>
> +static inline void audit_log_nfcfg(const char *name, u8 af, unsigned int nentries,
> +                                  enum audit_nfcfgop op)
> +{
> +       if (audit_enabled)
> +               __audit_log_nfcfg(name, af, nentries, op);

Do we want a dummy check here too?  Or do we always want to generate
this record (assuming audit is enabled) because it is a configuration
related record?

-- 
paul moore
www.paul-moore.com