]> git.proxmox.com Git - mirror_ubuntu-kernels.git/commit
HID: core: Fix deadloop in hid_apply_multiplier.
authorXin Zhao <xnzhao@google.com>
Mon, 30 Jan 2023 21:29:47 +0000 (21:29 +0000)
committerBenjamin Tissoires <benjamin.tissoires@redhat.com>
Mon, 6 Feb 2023 09:57:27 +0000 (10:57 +0100)
commitea427a222d8bdf2bc1a8a6da3ebe247f7dced70c
treedad4f7053cb7b774acad910be5bbe6e98efb2adc
parentcb963b2c011a62838852c902eccb3f72e5d3dbb6
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>
drivers/hid/hid-core.c