CVE-2023-52477

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

usb: hub: Guard against accesses to uninitialized BOS descriptors

Many functions in drivers/usb/core/hub.c and drivers/usb/core/hub.h access fields inside udev->bos without checking if it was allocated and initialized. If usb_get_bos_descriptor() fails for whatever reason, udev->bos will be NULL and those accesses will result in a crash:

BUG: kernel NULL pointer dereference, address: 0000000000000018 PGD 0 P4D 0 Oops: 0000 [#1] PREEMPT SMP NOPTI CPU: 5 PID: 17818 Comm: kworker/5:1 Tainted: G W 5.15.108-18910-gab0e1cb584e1 #1 <HASH:1f9e 1> Hardware name: Google Kindred/Kindred, BIOS Google_Kindred.12672.413.0 02/03/2021 Workqueue: usb_hub_wq hub_event RIP: 0010:hub_port_reset+0x193/0x788 Code: 89 f7 e8 20 f7 15 00 48 8b 43 08 80 b8 96 03 00 00 03 75 36 0f b7 88 92 03 00 00 81 f9 10 03 00 00 72 27 48 8b 80 a8 03 00 00 <48> 83 78 18 00 74 19 48 89 df 48 8b 75 b0 ba 02 00 00 00 4c 89 e9 RSP: 0018:ffffab740c53fcf8 EFLAGS: 00010246 RAX: 0000000000000000 RBX: ffffa1bc5f678000 RCX: 0000000000000310 RDX: fffffffffffffdff RSI: 0000000000000286 RDI: ffffa1be9655b840 RBP: ffffab740c53fd70 R08: 00001b7d5edaa20c R09: ffffffffb005e060 R10: 0000000000000001 R11: 0000000000000000 R12: 0000000000000000 R13: ffffab740c53fd3e R14: 0000000000000032 R15: 0000000000000000 FS: 0000000000000000(0000) GS:ffffa1be96540000(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 CR2: 0000000000000018 CR3: 000000022e80c005 CR4: 00000000003706e0 Call Trace: hub_event+0x73f/0x156e ? hub_activate+0x5b7/0x68f process_one_work+0x1a2/0x487 worker_thread+0x11a/0x288 kthread+0x13a/0x152 ? process_one_work+0x487/0x487 ? kthread_associate_blkcg+0x70/0x70 ret_from_fork+0x1f/0x30

Fall back to a default behavior if the BOS descriptor isnt accessible and skip all the functionalities that depend on it: LPM support checks, Super Speed capabilitiy checks, U1/U2 states setup.

Weakness

The product dereferences a pointer that it expects to be valid but is NULL.

Affected Software

Potential Mitigations

References

• https://git.kernel.org/stable/c/136f69a04e71ba3458d137aec3bb2ce1232c0289
• https://git.kernel.org/stable/c/241f230324337ed5eae3846a554fb6d15169872c
• https://git.kernel.org/stable/c/528f0ba9f7a4bc1b61c9b6eb591ff97ca37cac6b
• https://git.kernel.org/stable/c/6ad3e9fd3632106696692232bf7ff88b9f7e1bc3
• https://git.kernel.org/stable/c/8e7346bfea56453e31b7421c1c17ca2fb9ed613d
• https://git.kernel.org/stable/c/c64e4dca9aefd232b17ac4c779b608b286654e81
• https://git.kernel.org/stable/c/f74a7afc224acd5e922c7a2e52244d891bbe44ee
• https://git.kernel.org/stable/c/fb9895ab9533534335fa83d70344b397ac862c81
• https://git.kernel.org/stable/c/136f69a04e71ba3458d137aec3bb2ce1232c0289
• https://git.kernel.org/stable/c/241f230324337ed5eae3846a554fb6d15169872c
• https://git.kernel.org/stable/c/528f0ba9f7a4bc1b61c9b6eb591ff97ca37cac6b
• https://git.kernel.org/stable/c/6ad3e9fd3632106696692232bf7ff88b9f7e1bc3
• https://git.kernel.org/stable/c/8e7346bfea56453e31b7421c1c17ca2fb9ed613d
• https://git.kernel.org/stable/c/c64e4dca9aefd232b17ac4c779b608b286654e81
• https://git.kernel.org/stable/c/f74a7afc224acd5e922c7a2e52244d891bbe44ee
• https://git.kernel.org/stable/c/fb9895ab9533534335fa83d70344b397ac862c81