perf_counter: Fix buffer overflow in perf_copy_attr()
If we pass a big size data over perf_counter_open() syscall,
the kernel will copy this data to a small buffer, it will
cause kernel crash.
This bug makes the kernel unsafe and non-root local user can
trigger it.
Signed-off-by: Xiao Guangrong <xiaoguangrong@cn.fujitsu.com>
Acked-by: Peter Zijlstra <peterz@infradead.org>
Acked-by: Paul Mackerras <paulus@samba.org>
Cc: <stable@kernel.org>
LKML-Reference: <4AAF37D4.5010706@cn.fujitsu.com>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
diff --git a/kernel/perf_counter.c b/kernel/perf_counter.c
index d7cbc57..a67a1dc 100644
--- a/kernel/perf_counter.c
+++ b/kernel/perf_counter.c
@@ -4171,6 +4171,7 @@
if (val)
goto err_size;
}
+ size = sizeof(*attr);
}
ret = copy_from_user(attr, uattr, size);