ASoC: SOF: ipc3-control: Fix heap overflow in bytes_ext put/get

Overview

In the Linux kernel, the following vulnerability has been resolved:

ASoC: SOF: ipc3-control: Fix heap overflow in bytes_ext put/get

The ipc_control_data buffer is allocated as kzalloc(max_size), where max_size covers the entire struct sof_ipc_ctrl_data including its flexible array payload. However, the bounds checks in bytes_ext_put and _bytes_ext_get compared user data lengths against max_size directly, ignoring that cdata->data sits at an offset of sizeof(struct sof_ipc_ctrl_data) bytes into the allocation.

This allowed writing up to sizeof(struct sof_ipc_ctrl_data) bytes past the end of the heap buffer from unprivileged userspace via the ALSA TLV kcontrol interface, and similarly allowed over-reading adjacent heap data on the get path.

Fix all bounds checks to subtract sizeof(*cdata) from max_size so they reflect the actual space available at the cdata->data offset. Also fix the error-path restore in bytes_ext_put which wrote to cdata->data instead of cdata, causing the same overflow.

Affected

• Linux >= 67ec2a091630c28ea8d05db2bd7178a05b04b7e6 < af4b437a463ac0482ba705434a44da06783778e6
• Linux >= 67ec2a091630c28ea8d05db2bd7178a05b04b7e6 < 1adde1941bba7b0d7104b86ed819d48d81cb0ad9
• Linux >= 67ec2a091630c28ea8d05db2bd7178a05b04b7e6 < eaa67e139c9217099e2a7b717aeeb46c65de3494
• Linux >= 67ec2a091630c28ea8d05db2bd7178a05b04b7e6 < 121577383b5cf221e86581e0f2bcca4c66f17469
• Linux >= 67ec2a091630c28ea8d05db2bd7178a05b04b7e6 < f4933e1d11b97b6a0951648b7c3e53850e1b33a9
• Linux >= 67ec2a091630c28ea8d05db2bd7178a05b04b7e6 < fd46668d538993218eea19c6925c868ac0f2630c
• Linux 5.18

Remediation

Refer to the linked advisories for vendor-supplied fixes and affected version ranges.