linux-kernel - [PATCH v2] HID: hid-input: clear unmapped usages

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-next>] [day] [month] [year] [list]

Message-ID: <20191207210518.GA181006@dtor-ws>
Date:   Sat, 7 Dec 2019 13:05:18 -0800
From:   Dmitry Torokhov <dmitry.torokhov@...il.com>
To:     Jiri Kosina <jikos@...nel.org>,
        Benjamin Tissoires <benjamin.tissoires@...hat.com>
Cc:     Greg Kroah-Hartman <gregkh@...uxfoundation.org>,
        linux-input@...r.kernel.org, linux-kernel@...r.kernel.org
Subject: [PATCH v2] HID: hid-input: clear unmapped usages

We should not be leaving half-mapped usages with potentially invalid
keycodes, as that may confuse hidinput_find_key() when the key is located
by index, which may end up feeding way too large keycode into the VT
keyboard handler and cause OOB write there:

BUG: KASAN: global-out-of-bounds in clear_bit include/asm-generic/bitops-instrumented.h:56 [inline]
BUG: KASAN: global-out-of-bounds in kbd_keycode drivers/tty/vt/keyboard.c:1411 [inline]
BUG: KASAN: global-out-of-bounds in kbd_event+0xe6b/0x3790 drivers/tty/vt/keyboard.c:1495
Write of size 8 at addr ffffffff89a1b2d8 by task syz-executor108/1722
...
 kbd_keycode drivers/tty/vt/keyboard.c:1411 [inline]
 kbd_event+0xe6b/0x3790 drivers/tty/vt/keyboard.c:1495
 input_to_handler+0x3b6/0x4c0 drivers/input/input.c:118
 input_pass_values.part.0+0x2e3/0x720 drivers/input/input.c:145
 input_pass_values drivers/input/input.c:949 [inline]
 input_set_keycode+0x290/0x320 drivers/input/input.c:954
 evdev_handle_set_keycode_v2+0xc4/0x120 drivers/input/evdev.c:882
 evdev_do_ioctl drivers/input/evdev.c:1150 [inline]

Reported-by: syzbot+19340dff067c2d3835c0@...kaller.appspotmail.com
Signed-off-by: Dmitry Torokhov <dmitry.torokhov@...il.com>
---

v2: fixed up interaction with hid-multitouch according to Benjamin's
feedback

Please consider tagging for stable.

 drivers/hid/hid-input.c | 16 ++++++++++++----
 1 file changed, 12 insertions(+), 4 deletions(-)

diff --git a/drivers/hid/hid-input.c b/drivers/hid/hid-input.c
index 63855f275a38..9428f49fd218 100644
--- a/drivers/hid/hid-input.c
+++ b/drivers/hid/hid-input.c
@@ -1132,9 +1132,15 @@ static void hidinput_configure_usage(struct hid_input *hidinput, struct hid_fiel
 	}
 
 mapped:
-	if (device->driver->input_mapped && device->driver->input_mapped(device,
-				hidinput, field, usage, &bit, &max) < 0)
-		goto ignore;
+	if (device->driver->input_mapped &&
+	    device->driver->input_mapped(device, hidinput, field, usage,
+					 &bit, &max) < 0) {
+		/*
+		 * The driver indicated that no further generic handling
+		 * of the usage is desired.
+		 */
+		return;
+	}
 
 	set_bit(usage->type, input->evbit);
 
@@ -1215,9 +1221,11 @@ static void hidinput_configure_usage(struct hid_input *hidinput, struct hid_fiel
 		set_bit(MSC_SCAN, input->mscbit);
 	}
 
-ignore:
 	return;
 
+ignore:
+	usage->type = 0;
+	usage->code = 0;
 }
 
 static void hidinput_handle_scroll(struct hid_usage *usage,
-- 
2.24.0.393.g34dc348eaf-goog


-- 
Dmitry