From: David Howells <dhowells@xxxxxxxxxx>
Disallow the use of certain perf facilities that might allow userspace to
access kernel data.
Signed-off-by: David Howells <dhowells@xxxxxxxxxx>
Signed-off-by: Matthew Garrett <mjg59@xxxxxxxxxx>
Cc: Peter Zijlstra <peterz@xxxxxxxxxxxxx>
Cc: Ingo Molnar <mingo@xxxxxxxxxx>
Cc: Arnaldo Carvalho de Melo <acme@xxxxxxxxxx>
---
kernel/events/core.c | 6 ++++++
1 file changed, 6 insertions(+)
diff --git a/kernel/events/core.c b/kernel/events/core.c
index 3cd13a30f732..6ad3d83c091c 100644
--- a/kernel/events/core.c
+++ b/kernel/events/core.c
@@ -10461,6 +10461,12 @@ SYSCALL_DEFINE5(perf_event_open,
return -EINVAL;
}
+ if ((attr.sample_type & PERF_SAMPLE_REGS_INTR) &&
+ kernel_is_locked_down("PERF_SAMPLE_REGS_INTR",
+ LOCKDOWN_CONFIDENTIALITY))
+ /* REGS_INTR can leak data, lockdown must prevent this */
+ return -EPERM;
+
/* Only privileged users can get physical addresses */
if ((attr.sample_type & PERF_SAMPLE_PHYS_ADDR) &&
perf_paranoid_kernel() && !capable(CAP_SYS_ADMIN))
--
2.21.0.392.gf8f6787159e-goog
