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. Fixes: 73d1df2a7a10 ("Bluetooth: Add support for Read Unconfigured Index List command") Cc: stable@vger.kernel.org Signed-off-by: Aldo Ariel Panzardo --- net/bluetooth/mgmt.c | 8 ++------ 1 file changed, 2 insertions(+), 6 deletions(-) diff --git a/net/bluetooth/mgmt.c b/net/bluetooth/mgmt.c index 167d75e34..1f6691278 100644 --- a/net/bluetooth/mgmt.c +++ b/net/bluetooth/mgmt.c @@ -496,13 +496,9 @@ static int read_unconf_index_list(struct sock *sk, struct hci_dev *hdev, read_lock(&hci_dev_list_lock); - count = 0; - list_for_each_entry(d, &hci_dev_list, list) { - if (hci_dev_test_flag(d, HCI_UNCONFIGURED)) - count++; - } + count = list_count_nodes(&hci_dev_list); - rp_len = sizeof(*rp) + (2 * count); + rp_len = sizeof(*rp) + (sizeof(__le16) * count); rp = kmalloc(rp_len, GFP_ATOMIC); if (!rp) { read_unlock(&hci_dev_list_lock); -- 2.43.0