Em Wed, Aug 05, 2020 at 10:56:56AM +0300, Alexey Budankov escreveu: > > Open access to per-process monitoring for CAP_PERFMON only > privileged processes [1]. Extend ptrace_may_access() check > in perf_events subsystem with perfmon_capable() to simplify > user experience and make monitoring more secure by reducing > attack surface.
Acked-by: Arnaldo Carvalho de Melo <a...@redhat.com> Peter, can you pick up this one? You said it was ok last time we discussed this. - Arnaldo > [1] > https://lore.kernel.org/lkml/7776fa40-6c65-2aa6-1322-eb3a01201...@linux.intel.com/ > > Signed-off-by: Alexey Budankov <alexey.budan...@linux.intel.com> > --- > kernel/events/core.c | 4 ++-- > 1 file changed, 2 insertions(+), 2 deletions(-) > > diff --git a/kernel/events/core.c b/kernel/events/core.c > index 856d98c36f56..f50d528af444 100644 > --- a/kernel/events/core.c > +++ b/kernel/events/core.c > @@ -11587,7 +11587,7 @@ SYSCALL_DEFINE5(perf_event_open, > goto err_task; > > /* > - * Reuse ptrace permission checks for now. > + * Preserve ptrace permission check for backwards compatibility. > * > * We must hold exec_update_mutex across this and any potential > * perf_install_in_context() call for this new event to > @@ -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; > } > > -- > 2.24.1 > -- - Arnaldo
