From: David Howells <dhowells@xxxxxxxxxx> Disallow the creation of perf and ftrace kprobes when the kernel is locked down in confidentiality mode by preventing their registration. This prevents kprobes from being used to access kernel memory to steal crypto data, but continues to allow the use of kprobes from signed modules. Reported-by: Alexei Starovoitov <alexei.starovoitov@xxxxxxxxx> Signed-off-by: David Howells <dhowells@xxxxxxxxxx> Signed-off-by: Matthew Garrett <mjg59@xxxxxxxxxx> Cc: Naveen N. Rao <naveen.n.rao@xxxxxxxxxxxxx> Cc: Anil S Keshavamurthy <anil.s.keshavamurthy@xxxxxxxxx> Cc: davem@xxxxxxxxxxxxx Cc: Masami Hiramatsu <mhiramat@xxxxxxxxxx> --- kernel/trace/trace_kprobe.c | 3 +++ 1 file changed, 3 insertions(+) diff --git a/kernel/trace/trace_kprobe.c b/kernel/trace/trace_kprobe.c index d5fb09ebba8b..5c70acd80344 100644 --- a/kernel/trace/trace_kprobe.c +++ b/kernel/trace/trace_kprobe.c @@ -420,6 +420,9 @@ static int __register_trace_kprobe(struct trace_kprobe *tk) { int i, ret; + if (kernel_is_locked_down("Use of kprobes", LOCKDOWN_CONFIDENTIALITY)) + return -EPERM; + if (trace_probe_is_registered(&tk->tp)) return -EINVAL; -- 2.21.0.392.gf8f6787159e-goog