Bluetooth: MGMT: validate Add Extended Advertising Data length

Overview

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

Bluetooth: MGMT: validate Add Extended Advertising Data length

MGMT_OP_ADD_EXT_ADV_DATA is registered as a variable-length command, with MGMT_ADD_EXT_ADV_DATA_SIZE as the fixed header size. The handler then uses cp->adv_data_len and cp->scan_rsp_len to validate and copy cp->data, but it never checks that those bytes are part of the mgmt command payload.

A short command can therefore make add_ext_adv_data() pass an out-of-bounds pointer into tlv_data_is_valid(). If the bytes beyond the command buffer are addressable, they can also be copied into the advertising instance as scan response data, where the caller can read them back via MGMT_OP_GET_ADV_INSTANCE. The trigger requires CAP_NET_ADMIN in the initial user namespace; KASAN reports an 8-byte slab-out-of-bounds read.

Reject commands whose length does not match the fixed header plus both advertising data lengths before parsing cp->data.

Affected

• Linux >= 12410572833a283ce92fcf9679ca8a2f372097ee < 0d5104390b445e7bd664ad583837e4c04d892c9d
• Linux >= 12410572833a283ce92fcf9679ca8a2f372097ee < 14b01b9cba04e6ce82825f68fc4c4322fa4ffa43
• Linux >= 12410572833a283ce92fcf9679ca8a2f372097ee < a143ce77a5292f2c9285137433d879ce71d190a7
• Linux >= 12410572833a283ce92fcf9679ca8a2f372097ee < a6c75a3fad226ccbd8ef9110dee87c92c299f2ab
• Linux >= 12410572833a283ce92fcf9679ca8a2f372097ee < f1febe93ef075314615f970a87681d9ab86691d1
• Linux >= 12410572833a283ce92fcf9679ca8a2f372097ee < 0bc1a5a69f541859293d79db72bd7854ac48df51
• Linux >= 12410572833a283ce92fcf9679ca8a2f372097ee < d3f7d17960ed50df3a6709c5158caff989c8c905
• Linux 5.11

Remediation

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