[PATCH V31 23/25] Lock down perf when in confidentiality mode
From: Matthew Garrett <hidden>
Date: 2019-03-26 18:28:58
Also in:
linux-api, lkml
Subsystem:
performance events subsystem, the rest · Maintainers:
Peter Zijlstra, Ingo Molnar, Arnaldo Carvalho de Melo, Namhyung Kim, Linus Torvalds
From: David Howells <dhowells@redhat.com> 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 <redacted> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Ingo Molnar <mingo@redhat.com> Cc: Arnaldo Carvalho de Melo <acme@kernel.org> --- 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