This is a note to let you know that I've just added the patch titled
HID: core: Fix deadloop in hid_apply_multiplier.
to the 5.10-stable tree which can be found at:
http://www.kernel.org/git/?p=linux/kernel/git/stable/stable-queue.git;a=summary
The filename of the patch is:
hid-core-fix-deadloop-in-hid_apply_multiplier.patch
and it can be found in the queue-5.10 subdirectory.
If you, or anyone else, feels it should not be added to the stable tree,
please let <stable@xxxxxxxxxxxxxxx> know about it.
commit 5a083de227679a8ab69234e09b888804e012d916
Author: Xin Zhao <xnzhao@xxxxxxxxxx>
Date: Mon Jan 30 21:29:47 2023 +0000
HID: core: Fix deadloop in hid_apply_multiplier.
[ Upstream commit ea427a222d8bdf2bc1a8a6da3ebe247f7dced70c ]
The initial value of hid->collection[].parent_idx if 0. When
Report descriptor doesn't contain "HID Collection", the value
remains as 0.
In the meanwhile, when the Report descriptor fullfill
all following conditions, it will trigger hid_apply_multiplier
function call.
1. Usage page is Generic Desktop Ctrls (0x01)
2. Usage is RESOLUTION_MULTIPLIER (0x48)
3. Contain any FEATURE items
The while loop in hid_apply_multiplier will search the top-most
collection by searching parent_idx == -1. Because all parent_idx
is 0. The loop will run forever.
There is a Report Descriptor triggerring the deadloop
0x05, 0x01, // Usage Page (Generic Desktop Ctrls)
0x09, 0x48, // Usage (0x48)
0x95, 0x01, // Report Count (1)
0x75, 0x08, // Report Size (8)
0xB1, 0x01, // Feature
Signed-off-by: Xin Zhao <xnzhao@xxxxxxxxxx>
Link: https://lore.kernel.org/r/20230130212947.1315941-1-xnzhao@xxxxxxxxxx
Signed-off-by: Benjamin Tissoires <benjamin.tissoires@xxxxxxxxxx>
Signed-off-by: Sasha Levin <sashal@xxxxxxxxxx>
diff --git a/drivers/hid/hid-core.c b/drivers/hid/hid-core.c
index baadead947c8b..5f9ec1d1464a2 100644
--- a/drivers/hid/hid-core.c
+++ b/drivers/hid/hid-core.c
@@ -1197,6 +1197,7 @@ int hid_open_report(struct hid_device *device)
__u8 *end;
__u8 *next;
int ret;
+ int i;
static int (*dispatch_type[])(struct hid_parser *parser,
struct hid_item *item) = {
hid_parser_main,
@@ -1247,6 +1248,8 @@ int hid_open_report(struct hid_device *device)
goto err;
}
device->collection_size = HID_DEFAULT_NUM_COLLECTIONS;
+ for (i = 0; i < HID_DEFAULT_NUM_COLLECTIONS; i++)
+ device->collection[i].parent_idx = -1;
ret = -EINVAL;
while ((next = fetch_item(start, end, &item)) != NULL) {
