On 7/28/20 6:02 PM, Thiébaud Weksteen wrote: > On Tue, Jul 28, 2020 at 5:12 PM Paul Moore <paul@xxxxxxxxxxxxxx> wrote: >> Perhaps it would be helpful if you provided an example of how one >> would be expected to use this new tracepoint? That would help put >> things in the proper perspective. > The best example is the one I provided in the commit message, that is > using perf (or a perf equivalent), to hook onto that tracepoint. > >> Well, to be honest, the very nature of this tracepoint is duplicating >> the AVC audit record with a focus on using perf to establish a full >> backtrace at the expense of reduced information. At least that is how >> it appears to me. > I see both methods as complementary. By default, the kernel itself can > do some reporting (i.e avc message) on which process triggered the > denial, what was the context, etc. This is useful even in production > and doesn't require any extra tooling. > The case for adding this tracepoint can be seen as advanced debugging. > That is, once an avc denial has been confirmed, a developer can use > this tracepoint to surface the userland stacktrace. It requires more > userland tools and symbols on the userland binaries. I think from development view you would like to have a better way to trap this events in userspace. One idea that I have is is to have more outcomes from a rule. We have today allow, dontaudit, auditallow i think it would be good to have signal sent too. "signal-xxx-allow" for some set of signals. SIGBUS, SIGSEGV, SIGABRT maybe. That will be a good way to pickup the problem with a debugger or generate a a core file. I have also done some selinux trace functions. I think they collide with this set, but I think I can rebase them upon yours and see if they give some more functionality. I see this functionality very much needed in some form.
