lkml.org 
[lkml]   [2018]   [Nov]   [25]   [last100]   RSS Feed
Views: [wrap][no wrap]   [headers]  [forward] 
 
Messages in this thread
/
Date
From
SubjectRe: [RFC PATCH 1/3] audit: remove arch_f pointer from struct audit_krule
On 2018-02-15 15:42, Paul Moore wrote:
> On Mon, Feb 12, 2018 at 7:29 AM, Richard Guy Briggs <rgb@redhat.com> wrote:
> > The arch_f pointer was added to the struct audit_krule in commit:
> > e54dc2431d740a79a6bd013babade99d71b1714f ("audit signal recipients")
> >
> > This is only used on addition and deletion of rules which isn't time
> > critical and the arch field is likely to be one of the first fields,
> > easily found iterating over the field type. This isn't worth the
> > additional complexity and storage. Delete the field.
> >
> > Signed-off-by: Richard Guy Briggs <rgb@redhat.com>
> > ---
> > include/linux/audit.h | 1 -
> > kernel/auditfilter.c | 12 ++++++++----
> > 2 files changed, 8 insertions(+), 5 deletions(-)
>
> I haven't decided if I like the removal of arch_f or not, but I think
> I might know where your oops/panic is coming from, thoughts below ...

Have you decided yet if you like the removal of the arch_f pointer or
not? An updated v2 was provided the following day:
https://www.redhat.com/archives/linux-audit/2018-February/msg00059.html

I will send an updated patch if it seems worthwhile.

> > diff --git a/include/linux/audit.h b/include/linux/audit.h
> > index af410d9..64a3b0e 100644
> > --- a/include/linux/audit.h
> > +++ b/include/linux/audit.h
> > @@ -58,7 +58,6 @@ struct audit_krule {
> > u32 field_count;
> > char *filterkey; /* ties events to rules */
> > struct audit_field *fields;
> > - struct audit_field *arch_f; /* quick access to arch field */
> > struct audit_field *inode_f; /* quick access to an inode field */
> > struct audit_watch *watch; /* associated watch */
> > struct audit_tree *tree; /* associated watched tree */
> > diff --git a/kernel/auditfilter.c b/kernel/auditfilter.c
> > index 739a6d2..3343d1c 100644
> > --- a/kernel/auditfilter.c
> > +++ b/kernel/auditfilter.c
> > @@ -220,7 +220,14 @@ static inline int audit_match_class_bits(int class, u32 *mask)
> >
> > static int audit_match_signal(struct audit_entry *entry)
> > {
> > - struct audit_field *arch = entry->rule.arch_f;
> > + int i;
> > + struct audit_field *arch;
> > +
> > + for (i = 0; i < entry->rule.field_count; i++)
> > + if (entry->rule.fields[i].type == AUDIT_ARCH) {
> > + arch = &entry->rule.fields[i];
> > + break;
> > + }
>
> In the original code arch_f was initialized to NULL via the allocator
> so the arch local variable was guaranteed to have a valid value or
> NULL. Unfortunately, in your code if there is no AUDIT_ARCH field
> arch could remain uninitialized which I believe could lead to the
> oops/panic you are seeing.
>
> > if (!arch) {
> > /* When arch is unspecified, we must check both masks on biarch
> > @@ -496,9 +503,6 @@ static struct audit_entry *audit_data_to_entry(struct audit_rule_data *data,
> > if (!gid_valid(f->gid))
> > goto exit_free;
> > break;
> > - case AUDIT_ARCH:
> > - entry->rule.arch_f = f;
> > - break;
> > case AUDIT_SUBJ_USER:
> > case AUDIT_SUBJ_ROLE:
> > case AUDIT_SUBJ_TYPE:
> > --
> > 1.8.3.1
>
> --
> paul moore
> www.paul-moore.com
>
> --
> Linux-audit mailing list
> Linux-audit@redhat.com
> https://www.redhat.com/mailman/listinfo/linux-audit

- 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

\
 
 \ /
  Last update: 2018-11-25 18:12    [W:0.074 / U:3.660 seconds]
©2003-2020 Jasper Spaans|hosted at Digital Ocean and TransIP|Read the blog|Advertise on this site