On Mon, Jul 13, 2020 at 03:51:52PM -0300, Arnaldo Carvalho de Melo wrote: > > > diff --git a/kernel/events/core.c b/kernel/events/core.c > > > index 856d98c36f56..a2397f724c10 100644 > > > --- a/kernel/events/core.c > > > +++ b/kernel/events/core.c > > > @@ -11595,7 +11595,7 @@ SYSCALL_DEFINE5(perf_event_open, > > > * perf_event_exit_task() that could imply). > > > */ > > > err = -EACCES; > > > - if (!ptrace_may_access(task, PTRACE_MODE_READ_REALCREDS)) > > > + if (!perfmon_capable() && !ptrace_may_access(task, PTRACE_MODE_READ_REALCREDS)) > > > goto err_cred; > > > } > > > > > >> makes monitoring simpler and even more secure to use since Perf tool need > > >> not to start/stop/single-step and read/write registers and memory and so on > > >> like a debugger or strace-like tool. What do you think? > > > > > > I tend to agree, Peter? So this basically says that if CAP_PERFMON, we don't care about the ptrace() permissions? Just like how CAP_SYS_PTRACE would always allow the ptrace checks? I suppose that makes sense.
