Overview
About vulnerability
In the Linux kernel, the following vulnerability has been resolved:
hwmon: (pmbus/adm1266) reject short block-read responses in the GPIO accessors
adm1266_gpio_get() and adm1266_gpio_get_multiple() both compose the pin-status word as
pins_status = read_buf[0] + (read_buf[1] << 8);
right after i2c_smbus_read_block_data(), guarding only against an error return. A well-behaved device returns 2 bytes for GPIO_STATUS/PDIO_STATUS, but the helper happily reports a 0- or 1-byte response too. If the device returns 0 bytes, both read_buf slots are uninitialized stack memory; if it returns 1 byte, read_buf[1] is.
The composed value then flows through set_bit() into the caller’s *bits in adm1266_gpio_get_multiple(), or into the return value of adm1266_gpio_get(), and ends up in userspace via gpiolib (sysfs and the char-dev ioctls). That leaks a few bits of kernel stack per request on any device whose firmware glitch, bus error, or hostile slave produces a short block-read response.
Add the missing length check to both call sites and surface a short response as -EIO.
Details
- Affected product:
- AlmaLinux 9.2 ESU , TuxCare 9.6 ESU , Ubuntu 20.04 ELS
- Affected packages:
- linux-meta @ 5.4.0 (+3 more)
Fixes
KernelCare state
Live-patch status from KernelCare for each operating system.
| Operating system | Status | Covered kernels |
|---|---|---|
| Ubuntu 22.04 | Planned | — |