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In-Reply-To: <20190103202938.ntdfqdmyrr7stzh2@madcap2.tricolour.ca>
From:   Paul Moore <paul@paul-moore.com>
Date:   Thu, 3 Jan 2019 15:33:28 -0500
Message-ID: <CAHC9VhQTQuRnkF-8sJxwDvKbxJHvs5uLWsvLvL085SgyPiqLHQ@mail.gmail.com>
Subject: Re: [PATCH ghak90 (was ghak32) V4 01/10] audit: collect audit task parameters
To:     Richard Guy Briggs <rgb@redhat.com>
Cc:     containers@lists.linux-foundation.org, linux-api@vger.kernel.org,
        linux-audit@redhat.com, linux-kernel@vger.kernel.org,
        ebiederm@xmission.com, luto@kernel.org, dhowells@redhat.com,
        viro@zeniv.linux.org.uk, simo@redhat.com,
        Eric Paris <eparis@parisplace.org>,
        Serge Hallyn <serge@hallyn.com>
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On Thu, Jan 3, 2019 at 3:29 PM Richard Guy Briggs <rgb@redhat.com> wrote:
> I'm not sure what's going on here, but it looks like HTML-encoded reply
> quoting making the quoted text very difficult to read.  All the previous
> ">" have been converted to the HTML "&gt;" encoding.  Your most recent
> reply text looks mostly fine.

Not sure what happened either, I suspect gmail did something odd when
I saved them as drafts, but it has never done that before.  FWIW, I
generally batch up individual review comments for complex patchsets as
one often needs to review the entire set first before commenting.

The most recent reply to patch 0/10 wasn't saved as a draft before sending.

> On 2019-01-03 15:10, Paul Moore wrote:
> > On Thu, Nov 1, 2018 at 6:07 PM Richard Guy Briggs <rgb@redhat.com> wrote:
> > &gt; On 2018-10-19 19:15, Paul Moore wrote:
> > &gt; &gt; On Sun, Aug 5, 2018 at 4:32 AM Richard Guy Briggs
> > <rgb@redhat.com> wrote:
> > &gt; &gt; &gt; The audit-related parameters in struct task_struct
> > should ideally be
> > &gt; &gt; &gt; collected together and accessed through a standard audit API.
> > &gt; &gt; &gt;
> > &gt; &gt; &gt; Collect the existing loginuid, sessionid and
> > audit_context together in a
> > &gt; &gt; &gt; new struct audit_task_info called "audit" in struct task_struct.
> > &gt; &gt; &gt;
> > &gt; &gt; &gt; Use kmem_cache to manage this pool of memory.
> > &gt; &gt; &gt; Un-inline audit_free() to be able to always recover that memory.
> > &gt; &gt; &gt;
> > &gt; &gt; &gt; See: https://github.com/linux-audit/audit-kernel/issues/81
> > &gt; &gt; &gt;
> > &gt; &gt; &gt; Signed-off-by: Richard Guy Briggs <rgb@redhat.com>
> > &gt; &gt; &gt; ---
> > &gt; &gt; &gt;  include/linux/audit.h | 34 ++++++++++++++++++++++++----------
> > &gt; &gt; &gt;  include/linux/sched.h |  5 +----
> > &gt; &gt; &gt;  init/init_task.c      |  3 +--
> > &gt; &gt; &gt;  init/main.c           |  2 ++
> > &gt; &gt; &gt;  kernel/auditsc.c      | 51
> > ++++++++++++++++++++++++++++++++++++++++++---------
> > &gt; &gt; &gt;  kernel/fork.c         |  4 +++-
> > &gt; &gt; &gt;  6 files changed, 73 insertions(+), 26 deletions(-)
> > &gt; &gt;
> > &gt; &gt; ...
> > &gt; &gt;
> > &gt; &gt; &gt; diff --git a/include/linux/sched.h b/include/linux/sched.h
> > &gt; &gt; &gt; index 87bf02d..e117272 100644
> > &gt; &gt; &gt; --- a/include/linux/sched.h
> > &gt; &gt; &gt; +++ b/include/linux/sched.h
> > &gt; &gt; &gt; @@ -873,10 +872,8 @@ struct task_struct {
> > &gt; &gt; &gt;
> > &gt; &gt; &gt;         struct callback_head            *task_works;
> > &gt; &gt; &gt;
> > &gt; &gt; &gt; -       struct audit_context            *audit_context;
> > &gt; &gt; &gt;  #ifdef CONFIG_AUDITSYSCALL
> > &gt; &gt; &gt; -       kuid_t                          loginuid;
> > &gt; &gt; &gt; -       unsigned int                    sessionid;
> > &gt; &gt; &gt; +       struct audit_task_info          *audit;
> > &gt; &gt; &gt;  #endif
> > &gt; &gt; &gt;         struct seccomp                  seccomp;
> > &gt; &gt;
> > &gt; &gt; Prior to this patch audit_context was available regardless of
> > &gt; &gt; CONFIG_AUDITSYSCALL, after this patch the corresponding audit_context
> > &gt; &gt; is only available when CONFIG_AUDITSYSCALL is defined.
> > &gt;
> > &gt; This was intentional since audit_context is not used when AUDITSYSCALL is
> > &gt; disabled.  audit_alloc() was stubbed in that case to return 0.
> > audit_context()
> > &gt; returned NULL.
> > &gt;
> > &gt; The fact that audit_context was still present in struct task_struct was an
> > &gt; oversight in the two patches already accepted:
> > &gt;         ("audit: use inline function to get audit context")
> > &gt;         ("audit: use inline function to get audit context")
> > &gt; that failed to hide or remove it from struct task_struct when it
> > was no longer
> > &gt; relevant.
> >
> > Okay, in that case let's pull this out and fix this separately from
> > the audit container ID patchset.
> >
> > &gt; On further digging, loginuid and sessionid (and
> > audit_log_session_info) should
> > &gt; be part of CONFIG_AUDIT scope and not CONFIG_AUDITSYSCALL since
> > it is used in
> > &gt; CONFIG_CHANGE, ANOM_LINK, FEATURE_CHANGE(, INTEGRITY_RULE), none
> > of which are
> > &gt; otherwise dependent on AUDITSYSCALL.
> >
> > This looks like something else we should fix independently from this patchset.
> >
> > &gt; Looking ahead, contid should be treated like loginuid and
> > sessionid, which are
> > &gt; currently only available when syscall auditting is.
> >
> > That seems reasonable.  Eventually it would be great if we got rid of
> > CONFIG_AUDITSYSCALL, but that is a separate issue, and something that
> > is going to require work from the different arch/ABI folks to ensure
> > everything is working properly.
> >
> > &gt; Converting records from standalone to syscall and checking
> > audit_dummy_context
> > &gt; changes the nature of CONFIG_AUDIT/!CONFIG_AUDITSYSCALL separation.
> > &gt; eg: ANOM_LINK accompanied by PATH record (which needed CWD addition to be
> > &gt; complete anyways)
> > &gt;
> > &gt; &gt; &gt; diff --git a/init/main.c b/init/main.c
> > &gt; &gt; &gt; index 3b4ada1..6aba171 100644
> > &gt; &gt; &gt; --- a/init/main.c
> > &gt; &gt; &gt; +++ b/init/main.c
> > &gt; &gt; &gt; @@ -92,6 +92,7 @@
> > &gt; &gt; &gt;  #include <linux rodata_test.h="">
> > &gt; &gt; &gt;  #include <linux jump_label.h="">
> > &gt; &gt; &gt;  #include <linux mem_encrypt.h="">
> > &gt; &gt; &gt; +#include <linux audit.h="">
> > &gt; &gt; &gt;
> > &gt; &gt; &gt;  #include <asm io.h="">
> > &gt; &gt; &gt;  #include <asm bugs.h="">
> > &gt; &gt; &gt; @@ -721,6 +722,7 @@ asmlinkage __visible void __init
> > start_kernel(void)
> > &gt; &gt; &gt;         nsfs_init();
> > &gt; &gt; &gt;         cpuset_init();
> > &gt; &gt; &gt;         cgroup_init();
> > &gt; &gt; &gt; +       audit_task_init();
> > &gt; &gt; &gt;         taskstats_init_early();
> > &gt; &gt; &gt;         delayacct_init();
> > &gt; &gt;
> > &gt; &gt; It seems like we would need either init_struct_audit or
> > &gt; &gt; audit_task_init(), but not both, yes?
> > &gt;
> > &gt; One sets initial values of init task via an included struct,
> > other makes a call
> > &gt; to create the kmem cache.  Both seem appropriate to me unless we move the
> > &gt; initialization from a struct to assignments in audit_task_init(),
> > but I'm not
> > &gt; that comfortable separating the audit init values from the rest of the
> > &gt; task_struct init task initializers (though there are other
> > subsystems that need
> > &gt; to do so dynamically).
> >
> > My original thinking was focused on the use of init_struct_audit as an
> > initializer when audit_task_init() was already creating a kmem_cache
> > pool and a zero'd/init'd audit_task_info could be obtained via the
> > usual kmem_cache functions.  Alternatively, although I don't believe
> > it would be recommended for this case, would be to use
> > init_struct_audit as an init helper if we included the audit_task_info
> > struct directly in the task_struct, as opposed to a pointer.  What I
> > missed was the simple fact that you're only using init_struct_audit
> > for the init_task, which pretty much makes my original question rather
> > silly :)
> >
> > --
> > paul moore
> > www.paul-moore.com
>
> - RGB
>
> --
> Richard Guy Briggs <rgb@redhat.com>
> Sr. S/W Engineer, Kernel Security, Base Operating Systems
> Remote, Ottawa, Red Hat Canada
> IRC: rgb, SunRaycer
> Voice: +1.647.777.2635, Internal: (81) 32635


-- 
paul moore
www.paul-moore.com