CVE-2022-49470

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

Bluetooth: btmtksdio: fix use-after-free at btmtksdio_recv_event

We should not access skb buffer data anymore after hci_recv_frame was called.

[ 39.634809] BUG: KASAN: use-after-free in btmtksdio_recv_event+0x1b0 [ 39.634855] Read of size 1 at addr ffffff80cf28a60d by task kworker [ 39.634962] Call trace: [ 39.634974] dump_backtrace+0x0/0x3b8 [ 39.634999] show_stack+0x20/0x2c [ 39.635016] dump_stack_lvl+0x60/0x78 [ 39.635040] print_address_description+0x70/0x2f0 [ 39.635062] kasan_report+0x154/0x194 [ 39.635079] __asan_report_load1_noabort+0x44/0x50 [ 39.635099] btmtksdio_recv_event+0x1b0/0x1c4 [ 39.635129] btmtksdio_txrx_work+0x6cc/0xac4 [ 39.635157] process_one_work+0x560/0xc5c [ 39.635177] worker_thread+0x7ec/0xcc0 [ 39.635195] kthread+0x2d0/0x3d0 [ 39.635215] ret_from_fork+0x10/0x20 [ 39.635247] Allocated by task 0: [ 39.635260] (stack is not available) [ 39.635281] Freed by task 2392: [ 39.635295] kasan_save_stack+0x38/0x68 [ 39.635319] kasan_set_track+0x28/0x3c [ 39.635338] kasan_set_free_info+0x28/0x4c [ 39.635357] ____kasan_slab_free+0x104/0x150 [ 39.635374] __kasan_slab_free+0x18/0x28 [ 39.635391] slab_free_freelist_hook+0x114/0x248 [ 39.635410] kfree+0xf8/0x2b4 [ 39.635427] skb_free_head+0x58/0x98 [ 39.635447] skb_release_data+0x2f4/0x410 [ 39.635464] skb_release_all+0x50/0x60 [ 39.635481] kfree_skb+0xc8/0x25c [ 39.635498] hci_event_packet+0x894/0xca4 [bluetooth] [ 39.635721] hci_rx_work+0x1c8/0x68c [bluetooth] [ 39.635925] process_one_work+0x560/0xc5c [ 39.635951] worker_thread+0x7ec/0xcc0 [ 39.635970] kthread+0x2d0/0x3d0 [ 39.635990] ret_from_fork+0x10/0x20 [ 39.636021] The buggy address belongs to the object at ffffff80cf28a600 which belongs to the cache kmalloc-512 of size 512 [ 39.636039] The buggy address is located 13 bytes inside of 512-byte region [ffffff80cf28a600, ffffff80cf28a800)

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 Any operations using the original pointer are no longer valid because the memory “belongs” to the code that operates on the new pointer.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/01c6a899fa6be4f4cbf60c4f44f0f6691155415f
• https://git.kernel.org/stable/c/02ba31e09a26e8cd4582ac8e6163d80284997727
• https://git.kernel.org/stable/c/0fab6361c4ba17d1b43a991bef4238a3c1754d35
• https://git.kernel.org/stable/c/b3cec8a42fcd11d05313c724f27e01b1db77522c