lkml.org 
[lkml]   [2020]   [Mar]   [10]   [last100]   RSS Feed
Views: [wrap][no wrap]   [headers]  [forward] 
 
Messages in this thread
Patch in this message
/
From
Subject[PATCH 4.14 040/126] HID: core: fix off-by-one memset in hid_report_raw_event()
Date
From: Johan Korsnes <jkorsnes@cisco.com>

commit 5ebdffd25098898aff1249ae2f7dbfddd76d8f8f upstream.

In case a report is greater than HID_MAX_BUFFER_SIZE, it is truncated,
but the report-number byte is not correctly handled. This results in a
off-by-one in the following memset, causing a kernel Oops and ensuing
system crash.

Note: With commit 8ec321e96e05 ("HID: Fix slab-out-of-bounds read in
hid_field_extract") I no longer hit the kernel Oops as we instead fail
"controlled" at probe if there is a report too long in the HID
report-descriptor. hid_report_raw_event() is an exported symbol, so
presumabely we cannot always rely on this being the case.

Fixes: 966922f26c7f ("HID: fix a crash in hid_report_raw_event()
function.")
Signed-off-by: Johan Korsnes <jkorsnes@cisco.com>
Cc: Armando Visconti <armando.visconti@st.com>
Cc: Jiri Kosina <jkosina@suse.cz>
Cc: Alan Stern <stern@rowland.harvard.edu>
Signed-off-by: Jiri Kosina <jkosina@suse.cz>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

---
drivers/hid/hid-core.c | 4 +++-
1 file changed, 3 insertions(+), 1 deletion(-)

--- a/drivers/hid/hid-core.c
+++ b/drivers/hid/hid-core.c
@@ -1567,7 +1567,9 @@ int hid_report_raw_event(struct hid_devi

rsize = ((report->size - 1) >> 3) + 1;

- if (rsize > HID_MAX_BUFFER_SIZE)
+ if (report_enum->numbered && rsize >= HID_MAX_BUFFER_SIZE)
+ rsize = HID_MAX_BUFFER_SIZE - 1;
+ else if (rsize > HID_MAX_BUFFER_SIZE)
rsize = HID_MAX_BUFFER_SIZE;

if (csize < rsize) {

\
 
 \ /
  Last update: 2020-03-10 14:20    [W:0.677 / U:0.580 seconds]
©2003-2020 Jasper Spaans|hosted at Digital Ocean and TransIP|Read the blog|Advertise on this site