On 2018-07-24 16:33, Paul Moore wrote: > On Tue, Jul 24, 2018 at 10:06 AM Richard Guy Briggs <rgb@xxxxxxxxxx> wrote: > > On 2018-07-20 18:14, Paul Moore wrote: > > > On Wed, Jun 6, 2018 at 1:03 PM Richard Guy Briggs <rgb@xxxxxxxxxx> wrote: > > > > Audit events could happen in a network namespace outside of a task > > > > context due to packets received from the net that trigger an auditing > > > > rule prior to being associated with a running task. The network > > > > namespace could in use by multiple containers by association to the > > > > tasks in that network namespace. We still want a way to attribute > > > > these events to any potential containers. Keep a list per network > > > > namespace to track these audit container identifiiers. > > > > > > > > Add/increment the audit container identifier on: > > > > - initial setting of the audit container identifier via /proc > > > > - clone/fork call that inherits an audit container identifier > > > > - unshare call that inherits an audit container identifier > > > > - setns call that inherits an audit container identifier > > > > Delete/decrement the audit container identifier on: > > > > - an inherited audit container identifier dropped when child set > > > > - process exit > > > > - unshare call that drops a net namespace > > > > - setns call that drops a net namespace > > > > > > > > See: https://github.com/linux-audit/audit-kernel/issues/92 > > > > See: https://github.com/linux-audit/audit-testsuite/issues/64 > > > > See: https://github.com/linux-audit/audit-kernel/wiki/RFE-Audit-Container-ID > > > > Signed-off-by: Richard Guy Briggs <rgb@xxxxxxxxxx> > > > > --- > > > > include/linux/audit.h | 23 ++++++++++++++++ > > > > kernel/audit.c | 72 +++++++++++++++++++++++++++++++++++++++++++++++++++ > > > > kernel/auditsc.c | 5 ++++ > > > > kernel/nsproxy.c | 4 +++ > > > > 4 files changed, 104 insertions(+) > > ... > > > > > + } > > > > + if (!found) > > > > + return; > > > > + list_del(&cont->list); > > > > + if (refcount_dec_and_test(&cont->refcount)) > > > > + kfree(cont); > > > > > > Don't you want to dec_and_test first and only remove it from the list > > > if there are no other references? > > > > I don't think so. Let me try to describe it in prose to see if I > > understood this properly and see if this makes more sense: I want to > > remove this audit_contid list member from this net's audit_contid list > > and decrement unconditionally this member's refcount so it knows there > > is one less thing pointing at it and when there is no longer anything > > pointing at it, free it. > > Yep, sorry, my mistake, I was thinking the other way around (netns > going away) ... which actually, this patchset doesn't handle that does > it (I don't see any new code in audit_net_exit())? Is is in a later > patch? If so, it really should be in the same patch as this code to > prevent bisect nasties. I don't think any code is needed in audit_net_exit() other than a WARN() that the contid list is empty, since if a netns is going away, all its tasks would have exited (removing its contid from the list) or moved to a new nstns (moving its contid from this list to another netns). At worst, this is a memory leak and not a bad pointer dereference. > paul moore - RGB -- Richard Guy Briggs <rgb@xxxxxxxxxx> 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 -- To unsubscribe from this list: send the line "unsubscribe linux-api" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
