CVE-2022-49474

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

Bluetooth: fix dangling sco_conn and use-after-free in sco_sock_timeout

Connecting the same socket twice consecutively in sco_sock_connect() could lead to a race condition where two sco_conn objects are created but only one is associated with the socket. If the socket is closed before the SCO connection is established, the timer associated with the dangling sco_conn object wont be canceled. As the sock object is being freed, the use-after-free problem happens when the timer callback function sco_sock_timeout() accesses the socket. Heres the call trace:

dump_stack+0x107/0x163 ? refcount_inc+0x1c/ print_address_description.constprop.0+0x1c/0x47e ? refcount_inc+0x1c/0x7b kasan_report+0x13a/0x173 ? refcount_inc+0x1c/0x7b check_memory_region+0x132/0x139 refcount_inc+0x1c/0x7b sco_sock_timeout+0xb2/0x1ba process_one_work+0x739/0xbd1 ? cancel_delayed_work+0x13f/0x13f ? __raw_spin_lock_init+0xf0/0xf0 ? to_kthread+0x59/0x85 worker_thread+0x593/0x70e kthread+0x346/0x35a ? drain_workqueue+0x31a/0x31a ? kthread_bind+0x4b/0x4b ret_from_fork+0x1f/0x30

Weakness

The product reuses or references memory after it has been freed. At some point afterward, the memory may be allocated again and saved in another pointer, while the original pointer references a location somewhere within the new allocation. Any operations using the original pointer are no longer valid because the memory “belongs” to the code that operates on the new pointer.

Affected Software

Potential Mitigations

References

• https://git.kernel.org/stable/c/36c644c63bfcaee2d3a426f45e89a9cd09799318
• https://git.kernel.org/stable/c/390d82733a953c1fabf3de9c9618091a7a9c90a6
• https://git.kernel.org/stable/c/537f619dea4e3fa8ed1f8f938abffe3615794bcc
• https://git.kernel.org/stable/c/65d347cb39e2e6bd0c2a745ad7c928998ebb0162
• https://git.kernel.org/stable/c/6f55fac0af3531cf60d11369454c41f5fc81ab3f
• https://git.kernel.org/stable/c/7aa1e7d15f8a5b65f67bacb100d8fc033b21efa2
• https://git.kernel.org/stable/c/7d61dbd7311ab978d8ddac1749a758de4de00374
• https://git.kernel.org/stable/c/99df16007f4bbf9abfc3478cb17d10f0d7f8906e
• https://git.kernel.org/stable/c/9de3dc09e56f8deacd2bdbf4cecb71e11a312405