[PATCH 2/2] audit string fields interface + consumer
Serge E. Hallyn
serue at us.ibm.com
Wed Jan 18 18:02:10 UTC 2006
Quoting Timothy R. Chavez (tinytim at us.ibm.com):
> On Tue, 2006-01-17 at 17:19 -0500, Amy Griffis wrote:
> > Here is an update that incorporates changes based on Tim's feedback:
> > - sanity check for path with trailing /
> > - call path_release
> > - use audit_compare_watch
> >
> > and fixes panics due to the assumption of the existence of
> > rule->watch.
> >
> > diff --git a/kernel/audit.h b/kernel/audit.h
> > index f3b2a00..cc979e9 100644
> > --- a/kernel/audit.h
> > +++ b/kernel/audit.h
> > @@ -52,6 +52,12 @@ enum audit_state {
> > };
> >
> > /* Rule lists */
> > +struct audit_watch {
> > + char *path; /* watch insertion path */
> > + struct list_head mlist; /* entry in master_watchlist */
> > + struct list_head rules; /* associated rules */
> > +};
> > +
> > struct audit_field {
> > u32 type;
> > u32 val;
> > @@ -67,6 +73,8 @@ struct audit_krule {
> > u32 buflen; /* for data alloc on list rules */
> > u32 field_count;
> > struct audit_field fields[AUDIT_MAX_FIELDS];
> > + struct audit_watch *watch; /* associated watch */
> > + struct list_head rlist; /* entry in audit_watch.rules list */
> > };
>
> This may not really be that important, but if you switch to hlist_head
> you have a 4-byte savings, which is something...
>
> AUDIT_MAX_FIELDS defaults to 64, sizeof(audit_field) is 12-bytes...
> 768-bytes... 788-bytes per audit_krule?
Agree.
> Not sure if this qualifies as stack abuse though, which is why I say it
> might not be that important. I'm still a little concerned about
> AUDIT_MAX_FIELDS though... How much of that stack space is actually
> being used on average?
Why is it done that way? I assume ->fields would only need to be allocated
or expanded when rules are being added? So is there any reason not to
make ->fields and ->values dynamically allocated as needed?
More inanely, in
>+static int audit_to_watch(char *path, struct audit_krule *krule, int fidx)
>+{
>+ int err;
...
>+ err = -EINVAL;
>+ if (path[0] != '/' || path[f->val-1] == '/' ||
>+ krule->listnr != AUDIT_FILTER_EXIT ||
>+ f->op & ~AUDIT_EQUAL)
>+ return err;
...
>+ err = -ENOMEM;
>+ watch = kmalloc(sizeof(*watch), GFP_KERNEL);
>+ if (!watch)
>+ return err;
...
>+
>+ return 0;
>+}
There's really no point using err... :)
Anyway, still trying to get a full picture with all the patches to
analyze locking...
-serge
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