Re: [RFC PATCH ghak90 (was ghak32) V3 02/10] audit: log container info of syscalls

[Paul Moore]

On Wed, Jun 6, 2018 at 1:00 PM Richard Guy Briggs <rgb@xxxxxxxxxx> wrote:
> Create a new audit record AUDIT_CONTAINER to document the audit
> container identifier of a process if it is present.
>
> Called from audit_log_exit(), syscalls are covered.
>
> A sample raw event:
> type=SYSCALL msg=audit(1519924845.499:257): arch=c000003e syscall=257 success=yes exit=3 a0=ffffff9c a1=56374e1cef30 a2=241 a3=1b6 items=2 ppid=606 pid=635 auid=0 uid=0 gid=0 euid=0 suid=0 fsuid=0 egid=0 sgid=0 fsgid=0 tty=pts0 ses=3 comm="bash" exe="/usr/bin/bash" subj=unconfined_u:unconfined_r:unconfined_t:s0-s0:c0.c1023 key="tmpcontainerid"
> type=CWD msg=audit(1519924845.499:257): cwd="/root"
> type=PATH msg=audit(1519924845.499:257): item=0 name="/tmp/" inode=13863 dev=00:27 mode=041777 ouid=0 ogid=0 rdev=00:00 obj=system_u:object_r:tmp_t:s0 nametype= PARENT cap_fp=0000000000000000 cap_fi=0000000000000000 cap_fe=0 cap_fver=0
> type=PATH msg=audit(1519924845.499:257): item=1 name="/tmp/tmpcontainerid" inode=17729 dev=00:27 mode=0100644 ouid=0 ogid=0 rdev=00:00 obj=unconfined_u:object_r:user_tmp_t:s0 nametype=CREATE cap_fp=0000000000000000 cap_fi=0000000000000000 cap_fe=0 cap_fver=0
> type=PROCTITLE msg=audit(1519924845.499:257): proctitle=62617368002D6300736C65657020313B206563686F2074657374203E202F746D702F746D70636F6E7461696E65726964
> type=CONTAINER msg=audit(1519924845.499:257): op=task contid=123458
>
> See: https://github.com/linux-audit/audit-kernel/issues/90
> See: https://github.com/linux-audit/audit-userspace/issues/51
> See: https://github.com/linux-audit/audit-testsuite/issues/64
> See: https://github.com/linux-audit/audit-kernel/wiki/RFE-Audit-Container-ID
> Signed-off-by: Richard Guy Briggs <rgb@xxxxxxxxxx>
> ---
>  include/linux/audit.h      |  7 +++++++
>  include/uapi/linux/audit.h |  1 +
>  kernel/audit.c             | 23 +++++++++++++++++++++++
>  kernel/auditsc.c           |  3 +++
>  4 files changed, 34 insertions(+)

...

> --- a/include/uapi/linux/audit.h
> +++ b/include/uapi/linux/audit.h
> @@ -115,6 +115,7 @@
>  #define AUDIT_REPLACE          1329    /* Replace auditd if this packet unanswerd */
>  #define AUDIT_KERN_MODULE      1330    /* Kernel Module events */
>  #define AUDIT_FANOTIFY         1331    /* Fanotify access decision */
> +#define AUDIT_CONTAINER                1332    /* Container ID */

I'm not sure I'm completely sold on the AUDIT_CONTAINER_ID and
AUDIT_CONTAINER record type names.  From what I can tell
AUDIT_CONTAINER_ID seems to be used for audit container ID management
operations, e.g. setting the ID, whereas the AUDIT_CONTAINER is used
to tag events with the corresponding audit container ID.  Assuming
that is correct, it seems like AUDIT_CONTAINER might be better served
if it was named AUDIT_CONTAINER_ID and if we could change
AUDIT_CONTAINER_ID to AUDIT_CONTAINER_OP/MGMT/etc.  Thoughts?

>  #define AUDIT_AVC              1400    /* SE Linux avc denial or grant */
>  #define AUDIT_SELINUX_ERR      1401    /* Internal SE Linux Errors */
> diff --git a/kernel/audit.c b/kernel/audit.c
> index e7478cb..5e150c6 100644
> --- a/kernel/audit.c
> +++ b/kernel/audit.c
> @@ -2048,6 +2048,29 @@ void audit_log_session_info(struct audit_buffer *ab)
>         audit_log_format(ab, " auid=%u ses=%u", auid, sessionid);
>  }
>
> +/*
> + * audit_log_contid - report container info
> + * @tsk: task to be recorded
> + * @context: task or local context for record
> + * @op: contid string description
> + */
> +int audit_log_contid(struct task_struct *tsk,
> +                            struct audit_context *context, char *op)
> +{
> +       struct audit_buffer *ab;
> +
> +       if (!audit_contid_set(tsk))
> +               return 0;
> +       /* Generate AUDIT_CONTAINER record with container ID */
> +       ab = audit_log_start(context, GFP_KERNEL, AUDIT_CONTAINER);
> +       if (!ab)
> +               return -ENOMEM;
> +       audit_log_format(ab, "op=%s contid=%llu",
> +                        op, audit_get_contid(tsk));

Can you explain your reason for including an "op" field in this record
type?  I've been looking at the rest of the patches in this patchset
and it seems to be used more as an indicator of the record's
generating context rather than any sort of audit container ID
operation.

> +       audit_log_end(ab);
> +       return 0;
> +}

--
paul moore
www.paul-moore.com