input_id: check event mask

Check the capabilities/ev for the particular event class before testing bits in
that event class. This avoids testing potentially bogus data if the device does
not support that class of events at all.

Thanks to Dmitry Torokhov for pointing out!

1 files changed, 18 insertions, 7 deletions

diff --git a/extras/input_id/input_id.c b/extras/input_id/input_id.c
index 48097aa977..05bb085a03 100644
--- a/extras/input_id/input_id.c
+++ b/extras/input_id/input_id.c
@@ -64,12 +64,16 @@ static void get_cap_mask (struct udev_device *dev, const char* attr,
 }
 
 /* pointer devices */
-static void test_pointers (const unsigned long* bitmask_abs, const unsigned long* bitmask_key, const unsigned long* bitmask_rel)
+static void test_pointers (const unsigned long* bitmask_ev,
+                           const unsigned long* bitmask_abs, 
+                           const unsigned long* bitmask_key, 
+                           const unsigned long* bitmask_rel)
 {
 	int is_mouse = 0;
 	int is_touchpad = 0;
 
-	if (test_bit (ABS_X, bitmask_abs) && test_bit (ABS_Y, bitmask_abs)) {
+	if (test_bit (EV_ABS, bitmask_ev) && test_bit (EV_KEY, bitmask_ev) &&
+            test_bit (ABS_X, bitmask_abs) && test_bit (ABS_Y, bitmask_abs)) {
 		if (test_bit (BTN_STYLUS, bitmask_key) || test_bit (BTN_TOOL_PEN, bitmask_key))
 			puts("ID_INPUT_TABLET=1");
 		else if (test_bit (BTN_TOOL_FINGER, bitmask_key) && !test_bit (BTN_TOOL_PEN, bitmask_key))
@@ -84,7 +88,8 @@ static void test_pointers (const unsigned long* bitmask_abs, const unsigned long
 			is_mouse = 1;
 	}
 
-	if (test_bit (REL_X, bitmask_rel) && test_bit (REL_Y, bitmask_rel))
+	if (test_bit (EV_REL, bitmask_ev) && 
+            test_bit (REL_X, bitmask_rel) && test_bit (REL_Y, bitmask_rel))
 		is_mouse = 1;
 
 	if (is_mouse)
@@ -94,13 +99,17 @@ static void test_pointers (const unsigned long* bitmask_abs, const unsigned long
 }
 
 /* key like devices */
-static void test_key (const unsigned long* bitmask_key)
+static void test_key (const unsigned long* bitmask_ev, 
+                      const unsigned long* bitmask_key)
 {
 	unsigned i;
 	unsigned long acc;
 	unsigned long mask;
 
 	/* do we have any KEY_* capability? */
+        if (!test_bit (EV_KEY, bitmask_ev))
+                return;
+
 	acc = 0;
 	for (i = 0; i < BTN_MISC/BITS_PER_LONG; ++i)
 	    acc |= bitmask_key[i];
@@ -120,6 +129,7 @@ int main (int argc, char** argv)
 	struct udev_device *dev;
 
 	char devpath[PATH_MAX];
+	unsigned long bitmask_ev[NBITS(EV_MAX)];
 	unsigned long bitmask_abs[NBITS(ABS_MAX)];
 	unsigned long bitmask_key[NBITS(KEY_MAX)];
         unsigned long bitmask_rel[NBITS(REL_MAX)];
@@ -143,7 +153,7 @@ int main (int argc, char** argv)
 
 	/* walk up the parental chain until we find the real input device; the
 	 * argument is very likely a subdevice of this, like eventN */
-	while (dev != NULL && udev_device_get_sysattr_value(dev, "capabilities/key") == NULL)
+	while (dev != NULL && udev_device_get_sysattr_value(dev, "capabilities/ev") == NULL)
 		dev = udev_device_get_parent_with_subsystem_devtype(dev, "input", NULL);
 
 	/* not an "input" class device */
@@ -154,13 +164,14 @@ int main (int argc, char** argv)
 	 * program doesn't need to be called more than once per device */
 	puts("ID_INPUT=1");
 
+	get_cap_mask (dev, "capabilities/ev", bitmask_ev, sizeof (bitmask_ev));
 	get_cap_mask (dev, "capabilities/abs", bitmask_abs, sizeof (bitmask_abs));
 	get_cap_mask (dev, "capabilities/rel", bitmask_rel, sizeof (bitmask_rel));
 	get_cap_mask (dev, "capabilities/key", bitmask_key, sizeof (bitmask_key));
 
-	test_pointers(bitmask_abs, bitmask_key, bitmask_rel);
+	test_pointers(bitmask_ev, bitmask_abs, bitmask_key, bitmask_rel);
 
-	test_key(bitmask_key);
+	test_key(bitmask_ev, bitmask_key);
 
 	return 0;
 }