Affected: Alpaquita:23: linux-lts, Alpaquita:25: linux-lts, Alpaquita:stream: linux-lts

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

Bluetooth: L2CAP: fix out-of-bounds write in l2cap_ecred_connect

l2cap_chan_connect() tries to ensure there are no more than L2CAP_ECRED_CONN_SCID_MAX pending ECRED channels, so they fit in the same L2CAP_ECRED_CONN_REQ that l2cap_ecred_connect() constructs.

However, the check only counts deferred channels. If 6 L2CAP sockets are connected at the same time in order DDDDND (D=deferred, N=non-deferred), the last can bump the total to max+1. It results to one __le16 written out of bounds of the scid array, and an invalid ECRED_CONN_REQ being sent.

Fix by leaving room for the non-deferred pending ECRED channels in the counting in l2cap_chan_connect(), so the limit can't be exceeded.

Move counting under same critical section where the channel is added. Although race conditions involving this appear unreachable, it's easier to see.

Also add WARN_ON_ONCE check in l2cap_ecred_defer_connect() to make this less brittle.

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

Bluetooth: L2CAP: fix out-of-bounds write in l2cap_ecred_connect

l2cap_chan_connect() tries to ensure there are no more than L2CAP_ECRED_CONN_SCID_MAX pending ECRED channels, so they fit in the same L2CAP_ECRED_CONN_REQ that l2cap_ecred_connect() constructs.

However, the check only counts deferred channels. If 6 L2CAP sockets are connected at the same time in order DDDDND (D=deferred, N=non-deferred), the last can bump the total to max+1. It results to one __le16 written out of bounds of the scid array, and an invalid ECRED_CONN_REQ being sent.

Fix by leaving room for the non-deferred pending ECRED channels in the counting in l2cap_chan_connect(), so the limit can't be exceeded.

Move counting under same critical section where the channel is added. Although race conditions involving this appear unreachable, it's easier to see.

Also add WARN_ON_ONCE check in l2cap_ecred_defer_connect() to make this less brittle.

Affected: Ubuntu:16.04:LTS: linux-hwe-edge, Ubuntu:18.04:LTS: linux-aws-5.0, Ubuntu:18.04:LTS: linux-aws-5.3, Ubuntu:18.04:LTS: linux-azure, Ubuntu:18.04:LTS: linux-azure-5.3, Ubuntu:18.04:LTS: linux-azure-edge, Ubuntu:18.04:LTS: linux-gcp, Ubuntu:18.04:LTS: linux-gcp-5.3, Ubuntu:18.04:LTS: linux-gke-4.15, Ubuntu:18.04:LTS: linux-gke-5.4 and 193 more

In the Linux kernel, the following vulnerability has been resolved: Bluetooth: L2CAP: fix out-of-bounds write in l2cap_ecred_connect l2cap_chan_connect() tries to ensure there are no more than L2CAP_ECRED_CONN_SCID_MAX pending ECRED channels, so they fit in the same L2CAP_ECRED_CONN_REQ that l2cap_ecred_connect() constructs. However, the check only counts deferred channels. If 6 L2CAP sockets are connected at the same time in order DDDDND (D=deferred, N=non-deferred), the last can bump the total to max+1. It results to one __le16 written out of bounds of the scid array, and an invalid ECRED_CONN_REQ being sent. Fix by leaving room for the non-deferred pending ECRED channels in the counting in l2cap_chan_connect(), so the limit can't be exceeded. Move counting under same critical section where the channel is added. Although race conditions involving this appear unreachable, it's easier to see. Also add WARN_ON_ONCE check in l2cap_ecred_defer_connect() to make this less brittle.

Ein lokaler Angreifer kann mehrere Schwachstellen im Linux Kernel ausnutzen, um einen Denial of Service Zustand herbeizuführen oder nicht näher spezifizierten Angriff durchzuführen.