Description

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

usb: gadget: ncm: Avoid dropping datagrams of properly parsed NTBs

It is observed sometimes when tethering is used over NCM with Windows 11
as host, at some instances, the gadget_giveback has one byte appended at
the end of a proper NTB. When the NTB is parsed, unwrap call looks for
any leftover bytes in SKB provided by u_ether and if there are any pending
bytes, it treats them as a separate NTB and parses it. But in case the
second NTB (as per unwrap call) is faulty/corrupt, all the datagrams that
were parsed properly in the first NTB and saved in rx_list are dropped.

Adding a few custom traces showed the following:
[002] d..1 7828.532866: dwc3_gadget_giveback: ep1out:
req 000000003868811a length 1025/16384 zsI ==> 0
[002] d..1 7828.532867: ncm_unwrap_ntb: K: ncm_unwrap_ntb toprocess: 1025
[002] d..1 7828.532867: ncm_unwrap_ntb: K: ncm_unwrap_ntb nth: 1751999342
[002] d..1 7828.532868: ncm_unwrap_ntb: K: ncm_unwrap_ntb seq: 0xce67
[002] d..1 7828.532868: ncm_unwrap_ntb: K: ncm_unwrap_ntb blk_len: 0x400
[002] d..1 7828.532868: ncm_unwrap_ntb: K: ncm_unwrap_ntb ndp_len: 0x10
[002] d..1 7828.532869: ncm_unwrap_ntb: K: Parsed NTB with 1 frames

In this case, the giveback is of 1025 bytes and block length is 1024.
The rest 1 byte (which is 0x00) won't be parsed resulting in drop of
all datagrams in rx_list.

Same is case with packets of size 2048:
[002] d..1 7828.557948: dwc3_gadget_giveback: ep1out...

Classification

CVE ID: CVE-2024-27405

Affected Products

Vendor: Linux

Product: Linux

Exploit Prediction Scoring System (EPSS)

EPSS Score: 0.04% (probability of being exploited)

EPSS Percentile: 15.26% (scored less or equal to compared to others)

EPSS Date: 2025-02-04 (when was this score calculated)

References

https://git.kernel.org/stable/c/059285e04ebb273d32323fbad5431c5b94f77e48
https://git.kernel.org/stable/c/a31cf46d108dabce3df80b3e5c07661e24912151
https://git.kernel.org/stable/c/57ca0e16f393bb21d69734e536e383a3a4c665fd
https://git.kernel.org/stable/c/2cb66b62a5d64ccf09b0591ab86fb085fa491fc5
https://git.kernel.org/stable/c/35b604a37ec70d68b19dafd10bbacf1db505c9ca
https://git.kernel.org/stable/c/2b7ec68869d50ea998908af43b643bca7e54577e
https://git.kernel.org/stable/c/c7f43900bc723203d7554d299a2ce844054fab8e
https://git.kernel.org/stable/c/76c51146820c5dac629f21deafab0a7039bc3ccd

Timeline