linux-kernel - [PATCH 1/3] Input: mt - prevent balanced slot assignment to assign twice the slot

lists.openwall.net		lists / announce owl-users owl-dev john-users john-dev passwdqc-users yescrypt popa3d-users / oss-security kernel-hardening musl sabotage tlsify passwords / crypt-dev xvendor / Bugtraq Full-Disclosure linux-kernel linux-netdev linux-ext4 linux-hardening linux-cve-announce PHC
Open Source and information security mailing list archives

Hash Suite: Windows password security audit tool. GUI, reports in PDF.

[<prev] [next>] [<thread-prev] [thread-next>] [day] [month] [year] [list]

Date:	Mon, 30 Mar 2015 18:09:26 -0400
From:	Benjamin Tissoires <benjamin.tissoires@...hat.com>
To:	Dmitry Torokhov <dmitry.torokhov@...il.com>,
	Henrik Rydberg <rydberg@...math.org>,
	Hans de Goede <hdegoede@...hat.com>,
	Peter Hutterer <peter.hutterer@...hat.com>
Cc:	linux-input@...r.kernel.org, linux-kernel@...r.kernel.org
Subject: [PATCH 1/3] Input: mt - prevent balanced slot assignment to assign twice the slot

If two touches are under the dmax distance, it looks like they can now
be assigned to the same slot. Add a band aid to prevent such situation
and be able to use the balanced slot assignment.

Signed-off-by: Benjamin Tissoires <benjamin.tissoires@...hat.com>
---
 drivers/input/input-mt.c | 7 ++++++-
 1 file changed, 6 insertions(+), 1 deletion(-)

diff --git a/drivers/input/input-mt.c b/drivers/input/input-mt.c
index cb150a1..ad74f64 100644
--- a/drivers/input/input-mt.c
+++ b/drivers/input/input-mt.c
@@ -371,11 +371,16 @@ static void input_mt_set_slots(struct input_mt *mt,
 		*p = -1;
 
 	for (s = mt->slots; s != mt->slots + mt->num_slots; s++) {
+		bool found = false;
+
 		if (!input_mt_is_active(s))
 			continue;
 		for (p = slots; p != slots + num_pos; p++)
-			if (*w++ < 0)
+			if ((*w++ < 0) && !found) {
 				*p = s - mt->slots;
+				/* no break here: w won't be incremented */
+				found = true;
+			}
 	}
 
 	for (s = mt->slots; s != mt->slots + mt->num_slots; s++) {
-- 
2.3.4

--
To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to majordomo@...r.kernel.org
More majordomo info at  http://vger.kernel.org/majordomo-info.html
Please read the FAQ at  http://www.tux.org/lkml/