From 25a097f5204675550afb879ee18238ca917cba7a Mon Sep 17 00:00:00 2001
From: Peilin Ye <yepeilin.cs@gmail.com>
Date: Wed, 29 Jul 2020 07:37:12 -0400
Subject: [PATCH] HID: hiddev: Fix slab-out-of-bounds write in hiddev_ioctl_usage()
Git-commit: 25a097f5204675550afb879ee18238ca917cba7a
Patch-mainline: v5.9-rc3
References: git-fixes
`uref->usage_index` is not always being properly checked, causing
hiddev_ioctl_usage() to go out of bounds under some cases. Fix it.
Reported-by: syzbot+34ee1b45d88571c2fa8b@syzkaller.appspotmail.com
Link: https://syzkaller.appspot.com/bug?id=f2aebe90b8c56806b050a20b36f51ed6acabe802
Reviewed-by: Dan Carpenter <dan.carpenter@oracle.com>
Signed-off-by: Peilin Ye <yepeilin.cs@gmail.com>
Signed-off-by: Jiri Kosina <jkosina@suse.cz>
Acked-by: Takashi Iwai <tiwai@suse.de>
---
drivers/hid/usbhid/hiddev.c | 4 ++++
1 file changed, 4 insertions(+)
diff --git a/drivers/hid/usbhid/hiddev.c b/drivers/hid/usbhid/hiddev.c
index 4140dea693e9..4f97e6c12059 100644
--- a/drivers/hid/usbhid/hiddev.c
+++ b/drivers/hid/usbhid/hiddev.c
@@ -519,12 +519,16 @@ static noinline int hiddev_ioctl_usage(struct hiddev *hiddev, unsigned int cmd,
switch (cmd) {
case HIDIOCGUSAGE:
+ if (uref->usage_index >= field->report_count)
+ goto inval;
uref->value = field->value[uref->usage_index];
if (copy_to_user(user_arg, uref, sizeof(*uref)))
goto fault;
goto goodreturn;
case HIDIOCSUSAGE:
+ if (uref->usage_index >= field->report_count)
+ goto inval;
field->value[uref->usage_index] = uref->value;
goto goodreturn;
--
2.16.4