Affected: Linux

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

Bluetooth: hci_event: fix LE list UAF on reset

hci_cc_reset() clears the LE accept and resolving lists without taking hdev->lock. Other command-complete handlers serialize updates to these lists with that lock, and the debugfs readers hold it while walking them.

This permits the reset completion and a debugfs read to interleave as follows:

hci_rx_work debugfs reader ----------- -------------- lock hdev->lock fetch current entry list_del(entry) kfree(entry) read entry fields

The reader then dereferences a freed list entry and may follow its stale next pointer.

KASAN reported:

BUG: KASAN: slab-use-after-free in white_list_show+0x15f/0x180 Read of size 1 at addr ffff8881015dab16 by task poc/95

Call Trace: white_list_show+0x15f/0x180 seq_read_iter+0x3ff/0x1190 seq_read+0x267/0x3d0 vfs_read+0x177/0xa20 ksys_read+0xf7/0x1c0

Allocated by task 91: hci_bdaddr_list_add+0x1a6/0x3a0 hci_cc_le_add_to_accept_list+0xab/0x140 hci_cmd_complete_evt+0x26c/0x9a0 hci_event_packet+0x454/0xb20 hci_rx_work+0x293/0x730

Freed by task 90: kfree+0x131/0x3c0 hci_bdaddr_list_clear+0xd8/0x160 hci_cc_reset+0x28a/0x370 hci_cmd_complete_evt+0x26c/0x9a0 hci_event_packet+0x454/0xb20 hci_rx_work+0x293/0x730

Take hdev->lock around both list clears. T…