Re: [PATCH V3 0/6] namespaces: log namespaces per task

Eric Paris
2014-05-20T13:49:20Z

On Tue, 2014-05-20 at 09:12 -0400, Richard Guy Briggs wrote:
> The purpose is to track namespaces in use by logged processes from the
> perspective of init_*_ns.
>
> 1/6 defines a function to generate them and assigns them.
>
> Use a serial number per namespace (unique across one boot of one kernel)
> instead of the inode number (which is claimed to have had the right to change
> reserved and is not necessarily unique if there is more than one proc fs). It
> could be argued that the inode numbers have now become a defacto interface and
> can't change now, but I'm proposing this approach to see if this helps address
> some of the objections to the earlier patchset.
>
> 2/6 adds access functions to get to the serial numbers in a similar way to
> inode access for namespace proc operations.
>
> 3/6 implements, as suggested by Serge Hallyn, making these serial numbers
> available in /proc/self/ns/{ipc,mnt,net,pid,user,uts}_snum. I chose "snum"
> instead of "seq" for consistency with inum and there are a number of other uses
> of "seq" in the namespace code.
>
> 4/6 exposes proc's ns entries structure which lists a number of useful
> operations per namespace type for other subsystems to use.
>
> 5/6 provides an example of usage for audit_log_task_info() which is used by
> syscall audits, among others. audit_log_task() and audit_common_recv_message()
> would be other potential use cases.
>
> Proposed output format:
> This differs slightly from Aristeu's patch because of the label conflict with
> "pid=" due to including it in existing records rather than it being a seperate
> record. The serial numbers are printed in hex.
> type=SYSCALL msg=audit(1399651071.433:72): arch=c000003e syscall=272 success=yes exit=0 a0=40000000 a1=ffffffffffffffff a2=0 a3=22 items=0 ppid=1 pid=483 auid=4294967295 uid=0 gid=0 euid=0 suid=0 fsuid=0 egid=0 sgid=0 fsgid=0 tty=(none) ses=4294967295 comm="(t-daemon)" exe="/usr/lib/systemd/systemd" netns=97 utsns=2 ipcns=1 pidns=4 userns=3 mntns=5 subj=system_u:system_r:init_t:s0 key=(null)

I'm undecided if I'd rather see this as a separate NS_INFO record type.
It would mean we could filter them out of the logs...

Do we print out lots of pidns=0 for tasks not in a newly created NS? Do
we want to?

> 6/6 tracks the creation and deletion of of namespaces, listing the type of
> namespace instance, related namespace id if there is one and the newly minted
> serial number.
>
> Proposed output format:
> type=NS_INIT msg=audit(1400217435.706:94): pid=524 uid=0 auid=4294967295 ses=4294967295 subj=system_u:system_r:mount_t:s0 type=20000 old_snum=0 snum=a1 res=1

I'd love to be able to grep for netns=20 and find both the NS_INIT and
the SYSCALL/NS_INFO records, instead of having them named different
things. So basically I think you want to translate the type= into a
string for the old_X= and X=...