diff options
| author | Xin Zhao <xnzhao@google.com> | 2023-01-30 22:29:47 +0100 |
|---|---|---|
| committer | Benjamin Tissoires <benjamin.tissoires@redhat.com> | 2023-02-06 10:57:27 +0100 |
| commit | ea427a222d8bdf2bc1a8a6da3ebe247f7dced70c (patch) | |
| tree | dad4f7053cb7b774acad910be5bbe6e98efb2adc | |
| parent | HID: Ignore battery for Elan touchscreen on Asus TP420IA (diff) | |
| download | linux-ea427a222d8bdf2bc1a8a6da3ebe247f7dced70c.tar.xz linux-ea427a222d8bdf2bc1a8a6da3ebe247f7dced70c.zip | |
HID: core: Fix deadloop in hid_apply_multiplier.
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@google.com>
Link: https://lore.kernel.org/r/20230130212947.1315941-1-xnzhao@google.com
Signed-off-by: Benjamin Tissoires <benjamin.tissoires@redhat.com>
| -rw-r--r-- | drivers/hid/hid-core.c | 3 |
1 files changed, 3 insertions, 0 deletions
diff --git a/drivers/hid/hid-core.c b/drivers/hid/hid-core.c index 3e1803592bd4..5c72aef3d3dd 100644 --- a/drivers/hid/hid-core.c +++ b/drivers/hid/hid-core.c @@ -1202,6 +1202,7 @@ 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, @@ -1252,6 +1253,8 @@ 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) { |