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Date:   Wed, 21 Apr 2021 13:02:57 -0400
From:   Richard Guy Briggs <rgb@redhat.com>
To:     Paul Moore <paul@paul-moore.com>
Cc:     Greg Kroah-Hartman <gregkh@linuxfoundation.org>,
        linux-kernel@vger.kernel.org, Wenwen Wang <wang6495@umn.edu>
Subject: Re: [PATCH 085/190] Revert "audit: fix a memory leak bug"
Message-ID: <20210421170257.GJ3141668@madcap2.tricolour.ca>
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On 2021-04-21 12:18, Paul Moore wrote:
> On Wed, Apr 21, 2021 at 9:04 AM Greg Kroah-Hartman
> <gregkh@linuxfoundation.org> wrote:
> >
> > This reverts commit 70c4cf17e445264453bc5323db3e50aa0ac9e81f.
> >
> > Commits from @umn.edu addresses have been found to be submitted in "bad
> > faith" to try to test the kernel community's ability to review "known
> > malicious" changes.  The result of these submissions can be found in a
> > paper published at the 42nd IEEE Symposium on Security and Privacy
> > entitled, "Open Source Insecurity: Stealthily Introducing
> > Vulnerabilities via Hypocrite Commits" written by Qiushi Wu (University
> > of Minnesota) and Kangjie Lu (University of Minnesota).
> >
> > Because of this, all submissions from this group must be reverted from
> > the kernel tree and will need to be re-reviewed again to determine if
> > they actually are a valid fix.  Until that work is complete, remove this
> > change to ensure that no problems are being introduced into the
> > codebase.
> >
> > Cc: Wenwen Wang <wang6495@umn.edu>
> > Cc: Richard Guy Briggs <rgb@redhat.com>
> > Cc: Paul Moore <paul@paul-moore.com>
> > Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
> > ---
> >  kernel/auditfilter.c | 12 +++++-------
> >  1 file changed, 5 insertions(+), 7 deletions(-)
> 
> NACK on this revert.  I've looked at the original patch again this
> morning, and the original patch still looks correct and doesn't appear
> to introduce any new faults to the best of my understanding.

Agreed.  Though on review, a much simpler fix to my original patch that
caused this problem requiring this fix
	e85322d21cfebeac64f58a204e9adc0bc5c1e46f rgb 2014-10-02 ("audit: cull redundancy in audit_rule_change")
would have been the two-liner in the error path similar to the pattern
in audit_data_to_entry() error path would have been:

	if (entry->rule.tree)
		audit_put_tree(entry->rule.tree); /* that's the temporary one */

> > diff --git a/kernel/auditfilter.c b/kernel/auditfilter.c
> > index 333b3bcfc545..19f908b96000 100644
> > --- a/kernel/auditfilter.c
> > +++ b/kernel/auditfilter.c
> > @@ -1125,24 +1125,22 @@ int audit_rule_change(int type, int seq, void *data, size_t datasz)
> >         int err = 0;
> >         struct audit_entry *entry;
> >
> > +       entry = audit_data_to_entry(data, datasz);
> > +       if (IS_ERR(entry))
> > +               return PTR_ERR(entry);
> > +
> >         switch (type) {
> >         case AUDIT_ADD_RULE:
> > -               entry = audit_data_to_entry(data, datasz);
> > -               if (IS_ERR(entry))
> > -                       return PTR_ERR(entry);
> >                 err = audit_add_rule(entry);
> >                 audit_log_rule_change("add_rule", &entry->rule, !err);
> >                 break;
> >         case AUDIT_DEL_RULE:
> > -               entry = audit_data_to_entry(data, datasz);
> > -               if (IS_ERR(entry))
> > -                       return PTR_ERR(entry);
> >                 err = audit_del_rule(entry);
> >                 audit_log_rule_change("remove_rule", &entry->rule, !err);
> >                 break;
> >         default:
> > +               err = -EINVAL;
> >                 WARN_ON(1);
> > -               return -EINVAL;
> >         }
> >
> >         if (err || type == AUDIT_DEL_RULE) {
> > --
> > 2.31.1
> 
> -- 
> 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