Re: [PATCH ghak90 V8 13/16] audit: track container nesting

On Thu, Jan 30, 2020 at 2:28 PM Richard Guy Briggs <rgb(a)redhat.com&gt; wrote: > On 2020-01-22 16:29, Paul Moore wrote: > > On Tue, Dec 31, 2019 at 2:51 PM Richard Guy Briggs <rgb(a)redhat.com&gt; wrote: > > > > > > Track the parent container of a container to be able to filter and > > > report nesting. > > > > > > Now that we have a way to track and check the parent container of a > > > container, modify the contid field format to be able to report that > > > nesting using a carrat ("^") separator to indicate nesting. The > > > original field format was "contid=<contid>" for task-associated records > > > and "contid=<contid>[,<contid>[...]]" for network-namespace-associated > > > records. The new field format is > > > "contid=<contid>[^<contid>[...]][,<contid>[...]]". > > > > Let's make sure we always use a comma as a separator, even when > > recording the parent information, for example: > > "contid=<contid>[,^<contid>[...]][,<contid>[...]]" > > The intent here is to clearly indicate and separate nesting from > parallel use of several containers by one netns. If we do away with > that distinction, then we lose that inheritance accountability and > should really run the list through a "uniq" function to remove the > produced redundancies. This clear inheritance is something Steve was > looking for since tracking down individual events/records to show that > inheritance was not aways feasible due to rolled logs or search effort. Perhaps my example wasn't clear. I'm not opposed to the little carat/hat character indicating a container's parent, I just think it would be good to also include a comma *in*addition* to the carat/hat.

> > > Signed-off-by: Richard Guy Briggs <rgb(a)redhat.com&gt; > > > --- > > > include/linux/audit.h | 1 + > > > kernel/audit.c | 53 +++++++++++++++++++++++++++++++++++++++++++-------- > > > kernel/audit.h | 1 + > > > kernel/auditfilter.c | 17 ++++++++++++++++- > > > kernel/auditsc.c | 2 +- > > > 5 files changed, 64 insertions(+), 10 deletions(-) > > > > ... > > > > > diff --git a/kernel/audit.c b/kernel/audit.c > > > index ef8e07524c46..68be59d1a89b 100644 > > > --- a/kernel/audit.c > > > +++ b/kernel/audit.c > > > > > @@ -492,6 +493,7 @@ void audit_switch_task_namespaces(struct nsproxy *ns, struct task_struct *p) > > > audit_netns_contid_add(new->net_ns, contid); > > > } > > > > > > +void audit_log_contid(struct audit_buffer *ab, u64 contid); > > > > If we need a forward declaration, might as well just move it up near > > the top of the file with the rest of the declarations. > > Ok. > > > > +void audit_log_contid(struct audit_buffer *ab, u64 contid) > > > +{ > > > + struct audit_contobj *cont = NULL, *prcont = NULL; > > > + int h; > > > > It seems safer to pass the audit container ID object and not the u64. > > It would also be faster, but in some places it isn't available such as > for ptrace and signal targets. This also links back to the drop record > refcounts to hold onto the contobj until process exit, or signal > delivery. > > What we could do is to supply two potential parameters, a contobj and/or > a contid, and have it use the contobj if it is valid, otherwise, use the > contid, as is done for names and paths supplied to audit_log_name(). Let's not do multiple parameters, that begs for misuse, let's take the wrapper function route: func a(int id) { // important stuff } func ao(struct obj) { a(obj.id); } ... and we can add a comment that you *really* should be using the variant that passes an object.

> > > @@ -2705,9 +2741,10 @@ int audit_set_contid(struct task_struct *task, u64 contid) > > > if (!ab) > > > return rc; > > > > > > - audit_log_format(ab, > > > - "op=set opid=%d contid=%llu old-contid=%llu", > > > - task_tgid_nr(task), contid, oldcontid); > > > + audit_log_format(ab, "op=set opid=%d contid=", task_tgid_nr(task)); > > > + audit_log_contid(ab, contid); > > > + audit_log_format(ab, " old-contid="); > > > + audit_log_contid(ab, oldcontid); > > > > This is an interesting case where contid and old-contid are going to > > be largely the same, only the first (current) ID is going to be > > different; do we want to duplicate all of those IDs? > > At first when I read your comment, I thought we could just take contid > and drop oldcontid, but if it fails, we still want all the information, > so given the way I've set up the search code in userspace, listing only > the newest contid in the contid field and all the rest in oldcontid > could be a good compromise. This is along the lines of what I was thinking.

paul moore