The following commit has been merged into the perf/urgent branch of tip: Commit-ID: 45fd22da97c6125d8d0d35bd1791e7c0c4175279 Gitweb: https://git.kernel.org/tip/45fd22da97c6125d8d0d35bd1791e7c0c4175279 Author: Alexey Budankov <alexey.budankov@xxxxxxxxxxxxxxx> AuthorDate: Wed, 05 Aug 2020 10:56:56 +03:00 Committer: Ingo Molnar <mingo@xxxxxxxxxx> CommitterDate: Thu, 06 Aug 2020 15:03:20 +02:00 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@xxxxxxxxxxxxxxx/ Signed-off-by: Alexey Budankov <alexey.budankov@xxxxxxxxxxxxxxx> Signed-off-by: Ingo Molnar <mingo@xxxxxxxxxx> Acked-by: Peter Zijlstra <peterz@xxxxxxxxxxxxx> Link: https://lore.kernel.org/r/6e8392ff-4732-0012-2949-e1587709f0f6@xxxxxxxxxxxxxxx --- 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 78e69e1..41e0cef 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; }
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