perf/core: Fix the perf_cpu_time_max_percent check

commit 1572e45a924f254d9570093abde46430c3172e3d upstream.

Use "proc_dointvec_minmax" instead of "proc_dointvec" to check the input
value from user-space.

If not, we can set a big value and some vars will overflow like
"sysctl_perf_event_sample_rate" which will cause a lot of unexpected
problems.

Signed-off-by: Tan Xiaojun <tanxiaojun@huawei.com>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Cc: <acme@kernel.org>
Cc: <alexander.shishkin@linux.intel.com>
Cc: Alexander Shishkin <alexander.shishkin@linux.intel.com>
Cc: Arnaldo Carvalho de Melo <acme@redhat.com>
Cc: Jiri Olsa <jolsa@redhat.com>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Stephane Eranian <eranian@google.com>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Vince Weaver <vincent.weaver@maine.edu>
Link: http://lkml.kernel.org/r/1487829879-56237-1-git-send-email-tanxiaojun@huawei.com
Signed-off-by: Ingo Molnar <mingo@kernel.org>
Cc: Guenter Roeck <linux@roeck-us.net>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

diff --git a/kernel/events/core.c b/kernel/events/core.c
index b1d6b9888fbaa8487e805ee1fb51d7774f2aa2c1..cbc51826cb9424bfc98bf777a13f8d134fd2f73a 100644 (file)
--- a/kernel/events/core.c
+++ b/kernel/events/core.c
@@ -453,7 +453,7 @@ int perf_cpu_time_max_percent_handler(struct ctl_table *table, int write,
                                void __user *buffer, size_t *lenp,
                                loff_t *ppos)
 {
-       int ret = proc_dointvec(table, write, buffer, lenp, ppos);
+       int ret = proc_dointvec_minmax(table, write, buffer, lenp, ppos);
 
        if (ret || !write)
                return ret;