Re: [PATCH ghak90 V5 04/10] audit: log container info of syscalls

[Ondrej Mosnacek]

On Fri, Mar 15, 2019 at 7:34 PM Richard Guy Briggs <rgb@xxxxxxxxxx> wrote:
> Create a new audit record AUDIT_CONTAINER_ID 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=0 cap_fi=0 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=0 cap_fi=0 cap_fe=0 cap_fver=0
> type=PROCTITLE msg=audit(1519924845.499:257): proctitle=62617368002D6300736C65657020313B206563686F2074657374203E202F746D702F746D70636F6E7461696E65726964
> type=CONTAINER_ID msg=audit(1519924845.499:257): 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>
> Acked-by: Serge Hallyn <serge@xxxxxxxxxx>
> Acked-by: Steve Grubb <sgrubb@xxxxxxxxxx>
> Signed-off-by: Richard Guy Briggs <rgb@xxxxxxxxxx>

Barring one minor nit below,

Reviewed-by: Ondrej Mosnacek <omosnace@xxxxxxxxxx>

> ---
>  include/linux/audit.h      |  5 +++++
>  include/uapi/linux/audit.h |  1 +
>  kernel/audit.c             | 21 +++++++++++++++++++++
>  kernel/auditsc.c           |  2 ++
>  4 files changed, 29 insertions(+)
>
> diff --git a/include/linux/audit.h b/include/linux/audit.h
> index 301337776193..43438192ca2a 100644
> --- a/include/linux/audit.h
> +++ b/include/linux/audit.h
> @@ -199,6 +199,8 @@ static inline u64 audit_get_contid(struct task_struct *tsk)
>         return tsk->audit->contid;
>  }
>
> +extern void audit_log_contid(struct audit_context *context, u64 contid);
> +
>  extern u32 audit_enabled;
>  #else /* CONFIG_AUDIT */
>  static inline int audit_alloc(struct task_struct *task)
> @@ -265,6 +267,9 @@ static inline u64 audit_get_contid(struct task_struct *tsk)
>         return AUDIT_CID_UNSET;
>  }
>
> +static inline void audit_log_contid(struct audit_context *context, u64 contid)
> +{ }
> +
>  #define audit_enabled AUDIT_OFF
>  #endif /* CONFIG_AUDIT */
>
> diff --git a/include/uapi/linux/audit.h b/include/uapi/linux/audit.h
> index d475cf3b4d7f..a6383e28b2c8 100644
> --- 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_ID     1332    /* Container ID */
>
>  #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 b5c702abeb42..8cc0e88d7f2a 100644
> --- a/kernel/audit.c
> +++ b/kernel/audit.c
> @@ -2127,6 +2127,27 @@ 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
> + * @context: task or local context for record
> + * @contid: container ID to report
> + */
> +void audit_log_contid(struct audit_context *context, u64 contid)
> +{
> +       struct audit_buffer *ab;
> +
> +       if (!audit_contid_valid(contid))
> +               return;
> +       /* Generate AUDIT_CONTAINER_ID record with container ID */
> +       ab = audit_log_start(context, GFP_KERNEL, AUDIT_CONTAINER_ID);
> +       if (!ab)
> +               return;
> +       audit_log_format(ab, "contid=%llu", contid);

Just realized that you *might* get a compiler/static checker warning
since u64 could technically be something else than unsigned long long
on some arches... maybe this is not case in the kernel, but might be
safer to cast it to unsigned long long before passing to
audit_log_format(). Possibly there are similar occurrences in previous
(later) patches that I didn't (won't) notice.

> +       audit_log_end(ab);
> +       return;
> +}
> +EXPORT_SYMBOL(audit_log_contid);
> +
>  void audit_log_key(struct audit_buffer *ab, char *key)
>  {
>         audit_log_format(ab, " key=");
> diff --git a/kernel/auditsc.c b/kernel/auditsc.c
> index 8090eff7868d..a8c8b44b954d 100644
> --- a/kernel/auditsc.c
> +++ b/kernel/auditsc.c
> @@ -1548,6 +1548,8 @@ static void audit_log_exit(void)
>
>         audit_log_proctitle();
>
> +       audit_log_contid(context, audit_get_contid(current));
> +
>         /* Send end of event record to help user space know we are finished */
>         ab = audit_log_start(context, GFP_KERNEL, AUDIT_EOE);
>         if (ab)
> --
> 1.8.3.1
>


-- 
Ondrej Mosnacek <omosnace at redhat dot com>
Software Engineer, Security Technologies
Red Hat, Inc.