On Fri, Oct 23, 2020 at 4:40 PM Richard Guy Briggs <rgb@xxxxxxxxxx> wrote: > On 2020-10-22 21:21, Paul Moore wrote: > > On Wed, Oct 21, 2020 at 12:39 PM Richard Guy Briggs <rgb@xxxxxxxxxx> wrote: > > > Here is an exmple I was able to generate after updating the testsuite > > > script to include a signalling example of a nested audit container > > > identifier: > > > > > > ---- > > > type=PROCTITLE msg=audit(2020-10-21 10:31:16.655:6731) : proctitle=/usr/bin/perl -w containerid/test > > > type=CONTAINER_ID msg=audit(2020-10-21 10:31:16.655:6731) : contid=7129731255799087104^3333941723245477888 > > > type=OBJ_PID msg=audit(2020-10-21 10:31:16.655:6731) : opid=115583 oauid=root ouid=root oses=1 obj=unconfined_u:unconfined_r:unconfined_t:s0-s0:c0.c1023 ocomm=perl > > > type=CONTAINER_ID msg=audit(2020-10-21 10:31:16.655:6731) : contid=3333941723245477888 > > > type=OBJ_PID msg=audit(2020-10-21 10:31:16.655:6731) : opid=115580 oauid=root ouid=root oses=1 obj=unconfined_u:unconfined_r:unconfined_t:s0-s0:c0.c1023 ocomm=perl > > > type=CONTAINER_ID msg=audit(2020-10-21 10:31:16.655:6731) : contid=8098399240850112512^3333941723245477888 > > > type=OBJ_PID msg=audit(2020-10-21 10:31:16.655:6731) : opid=115582 oauid=root ouid=root oses=1 obj=unconfined_u:unconfined_r:unconfined_t:s0-s0:c0.c1023 ocomm=perl > > > type=SYSCALL msg=audit(2020-10-21 10:31:16.655:6731) : arch=x86_64 syscall=kill success=yes exit=0 a0=0xfffe3c84 a1=SIGTERM a2=0x4d524554 a3=0x0 items=0 ppid=115564 pid=115567 auid=root uid=root gid=root euid=root suid=root fsuid=root egid=root sgid=root fsgid=root tty=ttyS0 ses=1 comm=perl exe=/usr/bin/perl subj=unconfined_u:unconfined_r:unconfined_t:s0-s0:c0.c1023 key=testsuite-1603290671-AcLtUulY > > > ---- > > > > > > There are three CONTAINER_ID records which need some way of associating with OBJ_PID records. An additional CONTAINER_ID record would be present if the killing process itself had an audit container identifier. I think the most obvious way to connect them is with a pid= field in the CONTAINER_ID record. > > > > Using a "pid=" field as a way to link CONTAINER_ID records to other > > records raises a few questions. What happens if/when we need to > > represent those PIDs in the context of a namespace? Are we ever going > > to need to link to records which don't have a "pid=" field? I haven't > > done the homework to know if either of these are a concern right now, > > but I worry that this might become a problem in the future. > > Good point about PID namespaces in the future but those accompanying > records will already have to be conditioned for the PID namespace > context that is requesting it, so I don't see this as a showstopper. Possibly, it just gets very messy. Doubly so when you start looking at potentially adjusting for multiple audit daemons. Thankfully it doesn't look like using the PID is a good idea for other reasons. > I've forgotten about an important one we already hit, which is a network > event that only has a NETFILTER_PKT record, but in that case, there is > no ambiguity since there are no other records associated with that > event. So the second is already an issue now. Using > task_tgid_nr(current), in the contid testsuite script network event it > attributed it to ping which caused the event, but we cannot use this > since it wasn't triggered by a syscall and doesn't accurately reflect > the kernel thread that received it. It could just be set to zero for > network events. Possibly. It just seems like too much hackery to start; that's the stuff you do once it has been in a kernel release for years and need to find a workaround that doesn't break everything. I think we should aim a bit higher right now. > > The idea of using something like "item=" is interesting. As you > > mention, the "item=" field does present some overlap problems with the > > PATH record, but perhaps we can do something similar. What if we > > added a "record=" (or similar, I'm not worried about names at this > > point) to each record, reset to 0/1 at the start of each event, and > > when we needed to link records somehow we could add a "related=1,..,N" > > field. This would potentially be useful beyond just the audit > > container ID work. > > Does it make any sense to use the same keyword in each type of record > such as record/records as in PATH/SYSCALL: item/items ? That was mentioned above, if you can assure yourself and the rest of us that it can be safely reused I think that might be okay, but I'm not convinced that is safe at the moment. Although I will admit those are fears are not based on an exhaustive search through the code (or a determined "think"). > (I prefer 0-indexed like item=...) I have no preference on where we start the index, but it makes sense to keep the same index starting point as the PATH records. -- paul moore www.paul-moore.com
