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.
[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
