Bluetooth: mgmt: fix race in read_unconf_index_list()

Overview

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

Bluetooth: mgmt: fix race in read_unconf_index_list()

read_unconf_index_list() counts unconfigured controllers before allocating its response, then checks the device flags again while filling it.

hci_dev_list_lock stabilizes list membership, but it does not serialize the per-device flags. During asynchronous controller setup, the worker can set HCI_UNCONFIGURED and clear HCI_SETUP between the two passes. A controller omitted from the allocation count can then become eligible for the fill pass, causing an out-of-bounds write to rp->index[].

Allocate space for every device on hci_dev_list. Since list membership cannot change while hci_dev_list_lock is held, the response remains large enough regardless of flag transitions. The reported count and response length still include only eligible unconfigured controllers.

Affected

• Linux >= 73d1df2a7a1036a1f000e5f0ece6ade3e082b854 < 524e0450dd9a396f99a81b045219b0e2ea0dab57
• Linux >= 73d1df2a7a1036a1f000e5f0ece6ade3e082b854 < 8ddf962c76432a10a6cb80042875cbc48a9c056b
• Linux >= 73d1df2a7a1036a1f000e5f0ece6ade3e082b854 < 416546cd6a54e9b68f2b91bc680b1ee17dcd77a1
• Linux >= 73d1df2a7a1036a1f000e5f0ece6ade3e082b854 < 2e8bba0360d1379bfa8da47c8f5dadbb10a3fba1
• Linux >= 73d1df2a7a1036a1f000e5f0ece6ade3e082b854 < b5dbb41b212c50c095a4dbee3017a84fe94f033b
• Linux 3.17

Remediation

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