From: Anirudh Rayabharam <mail@anirudhrb.com>
To: Jiri Kosina <jikos@kernel.org>,
Benjamin Tissoires <benjamin.tissoires@redhat.com>
Cc: gregkh@linuxfoundation.org,
linux-kernel-mentees@lists.linuxfoundation.org,
Anirudh Rayabharam <mail@anirudhrb.com>,
syzbot+7c2bb71996f95a82524c@syzkaller.appspotmail.com,
linux-usb@vger.kernel.org, linux-input@vger.kernel.org,
linux-kernel@vger.kernel.org
Subject: [PATCH] usbhid: fix info leak in hid_submit_ctrl
Date: Sun, 25 Apr 2021 23:03:53 +0530 [thread overview]
Message-ID: <20210425173353.10231-1-mail@anirudhrb.com> (raw)
In hid_submit_ctrl(), the way of calculating the report length doesn't
take into account that report->size can be zero. When running the
syzkaller reproducer, a report of size 0 causes hid_submit_ctrl) to
calculate transfer_buffer_length as 16384. When this urb is passed to
the usb core layer, KMSAN reports an info leak of 16384 bytes.
To fix this, first modify hid_report_len() to account for the zero
report size case by using DIV_ROUND_UP for the division. Then, call it
from hid_submit_ctrl().
Reported-by: syzbot+7c2bb71996f95a82524c@syzkaller.appspotmail.com
Signed-off-by: Anirudh Rayabharam <mail@anirudhrb.com>
---
drivers/hid/usbhid/hid-core.c | 2 +-
include/linux/hid.h | 3 +--
2 files changed, 2 insertions(+), 3 deletions(-)
diff --git a/drivers/hid/usbhid/hid-core.c b/drivers/hid/usbhid/hid-core.c
index 86257ce6d619..4e9077363c96 100644
--- a/drivers/hid/usbhid/hid-core.c
+++ b/drivers/hid/usbhid/hid-core.c
@@ -374,7 +374,7 @@ static int hid_submit_ctrl(struct hid_device *hid)
raw_report = usbhid->ctrl[usbhid->ctrltail].raw_report;
dir = usbhid->ctrl[usbhid->ctrltail].dir;
- len = ((report->size - 1) >> 3) + 1 + (report->id > 0);
+ len = hid_report_len(report);
if (dir == USB_DIR_OUT) {
usbhid->urbctrl->pipe = usb_sndctrlpipe(hid_to_usb_dev(hid), 0);
usbhid->urbctrl->transfer_buffer_length = len;
diff --git a/include/linux/hid.h b/include/linux/hid.h
index 271021e20a3f..10e922cee4eb 100644
--- a/include/linux/hid.h
+++ b/include/linux/hid.h
@@ -1167,8 +1167,7 @@ static inline void hid_hw_wait(struct hid_device *hdev)
*/
static inline u32 hid_report_len(struct hid_report *report)
{
- /* equivalent to DIV_ROUND_UP(report->size, 8) + !!(report->id > 0) */
- return ((report->size - 1) >> 3) + 1 + (report->id > 0);
+ return DIV_ROUND_UP(report->size, 8) + (report->id > 0);
}
int hid_report_raw_event(struct hid_device *hid, int type, u8 *data, u32 size,
--
2.26.2
next reply other threads:[~2021-04-25 17:37 UTC|newest]
Thread overview: 6+ messages / expand[flat|nested] mbox.gz Atom feed top
2021-04-25 17:33 Anirudh Rayabharam [this message]
2021-05-05 12:42 ` [PATCH] usbhid: fix info leak in hid_submit_ctrl Jiri Kosina
2021-05-05 13:25 ` Benjamin Tissoires
2021-05-05 13:28 ` Jiri Kosina
2021-05-05 13:47 ` Benjamin Tissoires
2021-05-05 13:52 ` Jiri Kosina
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