linux-kernel - [PATCH v2 1/3] power: validate wakeup source before activating it.

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Date:	Tue,  5 May 2015 15:24:13 -0700
From:	Jin Qian <jinqian@...roid.com>
To:	"Rafael J. Wysocki" <rjw@...ysocki.net>,
	Pavel Machek <pavel@....cz>, Len Brown <len.brown@...el.com>,
	Greg Kroah-Hartman <gregkh@...uxfoundation.org>,
	linux-pm@...r.kernel.org, linux-kernel@...r.kernel.org
Cc:	Jin Qian <jinqian@...roid.com>
Subject: [PATCH v2 1/3] power: validate wakeup source before activating it.

A rogue wakeup source not registered in wakeup_sources list is not visible
from wakeup_sources_stats_show. Check if the wakeup source is registered
properly by looking at the timer function.

Signed-off-by: Jin Qian <jinqian@...roid.com>
---
 drivers/base/power/wakeup.c | 19 +++++++++++++++++++
 1 file changed, 19 insertions(+)

diff --git a/drivers/base/power/wakeup.c b/drivers/base/power/wakeup.c
index 7726200..5d866b9 100644
--- a/drivers/base/power/wakeup.c
+++ b/drivers/base/power/wakeup.c
@@ -14,6 +14,7 @@
 #include <linux/suspend.h>
 #include <linux/seq_file.h>
 #include <linux/debugfs.h>
+#include <linux/types.h>
 #include <trace/events/power.h>
 
 #include "power.h"
@@ -351,6 +352,19 @@ int device_set_wakeup_enable(struct device *dev, bool enable)
 }
 EXPORT_SYMBOL_GPL(device_set_wakeup_enable);
 
+/**
+ * validate_wakeup_source - validate the given wakeup source.
+ * @ws: Wakeup source to be validated.
+ */
+static bool validate_wakeup_source(struct wakeup_source *ws)
+{
+	/*
+	 * Use timer function to check if the given source is initialized
+	 * by wakeup_source_add.
+	 */
+	return ws->timer.function == pm_wakeup_timer_fn;
+}
+
 /*
  * The functions below use the observation that each wakeup event starts a
  * period in which the system should not be suspended.  The moment this period
@@ -391,6 +405,11 @@ static void wakeup_source_activate(struct wakeup_source *ws)
 {
 	unsigned int cec;
 
+	if (WARN_ON(!validate_wakeup_source(ws))) {
+		pr_err("unregistered wakeup source: %s\n", ws->name);
+		return;
+	}
+
 	/*
 	 * active wakeup source should bring the system
 	 * out of PM_SUSPEND_FREEZE state
-- 
2.2.0.rc0.207.ga3a616c

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