Messages in this thread |  | | Date | Wed, 19 Feb 2014 15:28:41 -0500 | From | Richard Guy Briggs <> | Subject | Re: [PATCH 4/5] audit: anchor all pid references in the initial pid namespace |
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On 13/12/30, Oleg Nesterov wrote: > On 12/23, Richard Guy Briggs wrote: > > > > Store and log all PIDs with reference to the initial PID namespace and > > use the access functions task_pid_nr() and task_tgid_nr() for task->pid > > and task->tgid rather than access them directly. > > At first glance this patch looks like a good cleanup, but... > > > @@ -429,6 +429,19 @@ static struct audit_entry *audit_data_to_entry(struct audit_rule_data *data, > > f->val = 0; > > } > > > > + if ((f->type == AUDIT_PID) || (f->type == AUDIT_PPID)) { > > + struct pid *pid; > > + rcu_read_lock(); > > + pid = find_vpid(f->val); > > + if (!pid) { > > + rcu_read_unlock(); > > + err = -ESRCH; > > + goto exit_free; > > + } > > + f->val = pid_nr(pid); > > + rcu_read_unlock(); > > + } > > I do not really understand this change, but this doesn't matter, I do > not understand audit.
Is this pid_t handed down from userspace a valid pid_t in its namespace? If not, generate an error. If it is, store its global pid_t for future comparisons. It might be better to store a struct task_struct * or a struct pid *, but then the comparison functions would have to change too, along with the rule reporting functions, which still report pid_t to userspace.
> However, I think this deserves a separate patch with the changelog.
All *that* would need a seperate patch...
> > @@ -278,9 +278,12 @@ static void dump_common_audit_data(struct audit_buffer *ab, > > } > > case LSM_AUDIT_DATA_TASK: > > tsk = a->u.tsk; > > - if (tsk && tsk->pid) { > > - audit_log_format(ab, " pid=%d comm=", tsk->pid); > > - audit_log_untrustedstring(ab, tsk->comm); > > + if (tsk) { > > + pid_t pid = task_pid_nr(tsk); > > + if (pid) { > > + audit_log_format(ab, " pid=%d comm=", pid); > > + audit_log_untrustedstring(ab, tsk->comm); > > Just curious, is it really possible that a->u.tsk is an idle thread?
No. It is possible a->u.tsk isn't filled in.
> Oleg.
- RGB
-- Richard Guy Briggs <rbriggs@redhat.com> Senior Software Engineer, Kernel Security, AMER ENG Base Operating Systems, Red Hat Remote, Ottawa, Canada Voice: +1.647.777.2635, Internal: (81) 32635, Alt: +1.613.693.0684x3545
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