From 45fd22da97c6125d8d0d35bd1791e7c0c4175279 Mon Sep 17 00:00:00 2001 From: Alexey Budankov Date: Wed, 5 Aug 2020 10:56:56 +0300 Subject: perf/core: Take over CAP_SYS_PTRACE creds to CAP_PERFMON capability 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-eb3a01201000@linux.intel.com/ Signed-off-by: Alexey Budankov Signed-off-by: Ingo Molnar Acked-by: Peter Zijlstra Link: https://lore.kernel.org/r/6e8392ff-4732-0012-2949-e1587709f0f6@linux.intel.com --- kernel/events/core.c | 4 ++-- 1 file changed, 2 insertions(+), 2 deletions(-) (limited to 'kernel') diff --git a/kernel/events/core.c b/kernel/events/core.c index 78e69e10482a..41e0cefb429b 100644 --- a/kernel/events/core.c +++ b/kernel/events/core.c @@ -11689,7 +11689,7 @@ 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 @@ -11697,7 +11697,7 @@ 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; } -- cgit v1.2.3