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Subject[PATCH 23/24] Lock down perf
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Date
Disallow the use of certain perf facilities that might allow userspace to
access kernel data.

Signed-off-by: David Howells <dhowells@redhat.com>
---

kernel/events/core.c | 5 +++++
1 file changed, 5 insertions(+)

diff --git a/kernel/events/core.c b/kernel/events/core.c
index fc1c330c6bd6..1922f2e0980a 100644
--- a/kernel/events/core.c
+++ b/kernel/events/core.c
@@ -10407,6 +10407,11 @@ SYSCALL_DEFINE5(perf_event_open,
return -EINVAL;
}

+ if ((attr.sample_type & PERF_SAMPLE_REGS_INTR) &&
+ kernel_is_locked_down("PERF_SAMPLE_REGS_INTR"))
+ /* 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))
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