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| author | Marc Zyngier <maz@kernel.org> | 2020-09-01 12:52:33 +0300 |
|---|---|---|
| committer | Benjamin Tissoires <benjamin.tissoires@gmail.com> | 2020-09-01 13:06:41 +0300 |
| commit | 35556bed836f8dc07ac55f69c8d17dce3e7f0e25 (patch) | |
| tree | cb19655e11b5f8113b444b5685ffc5b9372d5046 /drivers/hid | |
| parent | bce1305c0ece3dc549663605e567655dd701752c (diff) | |
| download | linux-35556bed836f8dc07ac55f69c8d17dce3e7f0e25.tar.xz | |
HID: core: Sanitize event code and type when mapping input
When calling into hid_map_usage(), the passed event code is
blindly stored as is, even if it doesn't fit in the associated bitmap.
This event code can come from a variety of sources, including devices
masquerading as input devices, only a bit more "programmable".
Instead of taking the event code at face value, check that it actually
fits the corresponding bitmap, and if it doesn't:
- spit out a warning so that we know which device is acting up
- NULLify the bitmap pointer so that we catch unexpected uses
Code paths that can make use of untrusted inputs can now check
that the mapping was indeed correct and bail out if not.
Cc: stable@vger.kernel.org
Signed-off-by: Marc Zyngier <maz@kernel.org>
Signed-off-by: Benjamin Tissoires <benjamin.tissoires@gmail.com>
Diffstat (limited to 'drivers/hid')
| -rw-r--r-- | drivers/hid/hid-input.c | 4 | ||||
| -rw-r--r-- | drivers/hid/hid-multitouch.c | 2 |
2 files changed, 6 insertions, 0 deletions
diff --git a/drivers/hid/hid-input.c b/drivers/hid/hid-input.c index b8eabf206e74..88e19996427e 100644 --- a/drivers/hid/hid-input.c +++ b/drivers/hid/hid-input.c @@ -1132,6 +1132,10 @@ static void hidinput_configure_usage(struct hid_input *hidinput, struct hid_fiel } mapped: + /* Mapping failed, bail out */ + if (!bit) + return; + if (device->driver->input_mapped && device->driver->input_mapped(device, hidinput, field, usage, &bit, &max) < 0) { diff --git a/drivers/hid/hid-multitouch.c b/drivers/hid/hid-multitouch.c index 3f94b4954225..e3152155c4b8 100644 --- a/drivers/hid/hid-multitouch.c +++ b/drivers/hid/hid-multitouch.c @@ -856,6 +856,8 @@ static int mt_touch_input_mapping(struct hid_device *hdev, struct hid_input *hi, code = BTN_0 + ((usage->hid - 1) & HID_USAGE); hid_map_usage(hi, usage, bit, max, EV_KEY, code); + if (!*bit) + return -1; input_set_capability(hi->input, EV_KEY, code); return 1; |