On Fri, 3 Mar 2017 19:19:47 -0500 Paul Moore <p...@paul-moore.com> wrote:
> On Tue, Feb 28, 2017 at 10:37 PM, Richard Guy Briggs <r...@redhat.com> wrote: > > Sorry, I forgot to include Cc: in this cover letter for context to the 4 > > alt patches. > > > > On 2017-02-28 22:15, Richard Guy Briggs wrote: > >> The background to this is: > >> https://github.com/linux-audit/audit-kernel/issues/8 > >> > >> In short, audit SYSCALL records for *init_module were occasionally > >> accompanied by hundreds to thousands of null PATH records. > >> > >> I chatted with Al Viro and Eric Paris about this Friday afternoon and > >> they seemed to vaguely recall this issue and didn't have any solid > >> recommendations as to what was the right thing to do (other than the > >> same suggestion from both that I won't print here). > >> > >> It was reproducible on a number of vintages of distributions with > >> default kernels, but triggering on very few of the many modules loaded > >> at boot time. It was reproduced with fs-nfs4 and nfsv4 modules on > >> tracefs, but there are reports of it also happening with debugfs. It > >> was triggering only in __audit_inode_child with a parent that was not > >> found in the task context's audit names_list. > > I'm no expert on the tracing system, but my understanding is that it > used to use debugfs but now prefers tracefs so perhaps depending on > the vintage of the kernel/userspace you will see it on either debugfs > or tracefs. I'm also guessing that module load order may have an > effect, maybe not. Note, when you mount debugfs, it automounts tracefs in debugfs/tracing. Userspace can also mount tracefs without debugfs. But tracing does not use debugfs anymore, even though it appears in the debugfs directory. > > >> I have four potential solutions listed in my order of preference and I'd > >> like to get some feedback about which one would be the most acceptable. > > >From an audit perspective, I'm generally not a fan of throwing away > information, especially since solution #4 seems to provide some basic > PATH information. Although I guess the issue is do we care about > tracefs/debugfs PATH records? I don't have enough context here to really understand what the issue is. Is there a problem when modules have trace events and when they are loaded, these trace events create files and directories in the tracefs file system? -- Steve
