Overview
About vulnerability
In the Linux kernel, the following vulnerability has been resolved:
Input: goodix - clamp the device-reported contact count
goodix_ts_read_input_report() copies the number of touch points reported by the device into an on-stack buffer
u8 point_data[2 + GOODIX_MAX_CONTACT_SIZE * GOODIX_MAX_CONTACTS];
which is sized for at most GOODIX_MAX_CONTACTS (10) contacts. The only runtime check bounds the per-interrupt count against ts->max_touch_num, but that value is taken verbatim from a 4-bit field of the device configuration block and is never clamped:
ts->max_touch_num = ts->config[MAX_CONTACTS_LOC] & 0x0f;
The nibble can be 0..15, so a malfunctioning, malicious or counterfeit controller (or an attacker tampering with the I2C bus) can advertise up to 15 contacts. goodix_ts_read_input_report() then accepts a touch_num of up to 15 and the second goodix_i2c_read() writes ts->contact_size * (touch_num - 1) bytes past the one-contact header into point_data - up to 30 bytes (45 with the 9-byte report format) beyond the 92-byte buffer: a stack out-of-bounds write.
Clamp max_touch_num to GOODIX_MAX_CONTACTS, the number of contacts point_data[] is sized for, when reading it from the configuration.
Details
- Affected product:
- AlmaLinux 9.2 ESU , Amazon Linux 2 ELS , CentOS 8.4 ELS , CentOS 8.5 ELS , CentOS Stream 8 ELS , Debian 10 ELS , Oracle Linux 7 ELS , TuxCare 9.6 ESU , Ubuntu 16.04 ELS , Ubuntu 18.04 ELS , Ubuntu 20.04 ELS
- Affected packages:
- linux @ 4.15.0 (+11 more)
Fixes
KernelCare state
Live-patch status from KernelCare for each operating system.
| Operating system | Status | Covered kernels |
|---|---|---|
| Debian 11 | Planned | — |
| Debian 11 cloud | Planned | — |
| Debian 12 | Planned | — |