lockdown: Lock down perf when in confidentiality mode
Disallow the use of certain perf facilities that might allow userspace to
access kernel data.
Signed-off-by: David Howells <dhowells@redhat.com>
Signed-off-by: Matthew Garrett <mjg59@google.com>
Reviewed-by: Kees Cook <keescook@chromium.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Ingo Molnar <mingo@redhat.com>
Cc: Arnaldo Carvalho de Melo <acme@kernel.org>
Signed-off-by: James Morris <jmorris@namei.org>
diff --git a/kernel/events/core.c b/kernel/events/core.c
index f85929c..8732f98 100644
--- a/kernel/events/core.c
+++ b/kernel/events/core.c
@@ -10798,6 +10798,13 @@ SYSCALL_DEFINE5(perf_event_open,
perf_paranoid_kernel() && !capable(CAP_SYS_ADMIN))
return -EACCES;
+ err = security_locked_down(LOCKDOWN_PERF);
+ if (err && (attr.sample_type & PERF_SAMPLE_REGS_INTR))
+ /* REGS_INTR can leak data, lockdown must prevent this */
+ return err;
+
+ err = 0;
+
/*
* In cgroup mode, the pid argument is used to pass the fd
* opened to the cgroup directory in cgroupfs. The cpu argument