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:
req 0000000011dfd96e length 2049/16384 zsI ==> 0
[002] d..1 7828.557949: ncm_unwrap_ntb: K: ncm_unwrap_ntb nth: 1751999342
[002] d..1 7828.557950: ncm_unwrap_ntb: K: ncm_unwrap_ntb blk_len: 0x800
Lecroy shows one byte coming in extra confirming that the byte is coming
in from PC:
Transfer 2959 - Bytes Transferred(1025) Timestamp((18.524 843 590)
- Transaction 8391 - Data(1025 bytes) Timestamp(18.524 843 590)
--- Packet 4063861
Data(1024 bytes)
Duration(2.117us) Idle(14.700ns) Timestamp(18.524 843 590)
--- Packet 4063863
Data(1 byte)
Duration(66.160ns) Time(282.000ns) Timestamp(18.524 845 722)
According to Windows driver, no ZLP is needed if wBlockLength is non-zero,
because the non-zero wBlockLength has already told the function side the
size of transfer to be expected. However, there are in-market NCM devices
that rely on ZLP as long as the wBlockLength is multiple of wMaxPacketSize.
To deal with such devices, it pads an extra 0 at end so the transfer is no
longer multiple of wMaxPacketSize.
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:
req 0000000011dfd96e length 2049/16384 zsI ==> 0
[002] d..1 7828.557949: ncm_unwrap_ntb: K: ncm_unwrap_ntb nth: 1751999342
[002] d..1 7828.557950: ncm_unwrap_ntb: K: ncm_unwrap_ntb blk_len: 0x800
Lecroy shows one byte coming in extra confirming that the byte is coming
in from PC:
Transfer 2959 - Bytes Transferred(1025) Timestamp((18.524 843 590)
- Transaction 8391 - Data(1025 bytes) Timestamp(18.524 843 590)
--- Packet 4063861
Data(1024 bytes)
Duration(2.117us) Idle(14.700ns) Timestamp(18.524 843 590)
--- Packet 4063863
Data(1 byte)
Duration(66.160ns) Time(282.000ns) Timestamp(18.524 845 722)
According to Windows driver, no ZLP is needed if wBlockLength is non-zero,
because the non-zero wBlockLength has already told the function side the
size of transfer to be expected. However, there are in-market NCM devices
that rely on ZLP as long as the wBlockLength is multiple of wMaxPacketSize.
To deal with such devices, it pads an extra 0 at end so the transfer is no
longer multiple of wMaxPacketSize.
Default status is the baseline for the product, each version can override it (e.g. patched versions marked unaffected).
| Vendor | Product | Default status | Versions | |||||||||||||||||||||||||||||||||
|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|
| Linux | Linux | unaffected |
|
|||||||||||||||||||||||||||||||||
| Linux | Linux | affected |
|
Configuration 1 [-]
|
Configuration 2 [-]
|
No data.
No data.
Subscriptions
Tracking
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Advisories
| Source | ID | Title |
|---|---|---|
 Debian DLA |
DLA-3840-1 | linux security update |
| Debian DLA |
DLA-3842-1 | linux-5.10 security update |
 Ubuntu USN |
USN-6820-1 | Linux kernel vulnerabilities |
| Ubuntu USN |
USN-6820-2 | Linux kernel (NVIDIA) vulnerabilities |
| Ubuntu USN |
USN-6821-1 | Linux kernel vulnerabilities |
| Ubuntu USN |
USN-6821-2 | Linux kernel vulnerabilities |
| Ubuntu USN |
USN-6821-3 | Linux kernel (AWS) vulnerabilities |
| Ubuntu USN |
USN-6821-4 | Linux kernel (Azure) vulnerabilities |
| Ubuntu USN |
USN-6828-1 | Linux kernel (Intel IoTG) vulnerabilities |
| Ubuntu USN |
USN-6831-1 | Linux kernel vulnerabilities |
| Ubuntu USN |
USN-6871-1 | Linux kernel (HWE) vulnerabilities |
| Ubuntu USN |
USN-6892-1 | Linux kernel (IBM) vulnerabilities |
| Ubuntu USN |
USN-6919-1 | Linux kernel vulnerabilities |
Fixes
Solution
No solution given by the vendor.
Workaround
No workaround given by the vendor.
References
History
Tue, 08 Apr 2025 16:15:00 +0000
| Type | Values Removed | Values Added |
|---|---|---|
| First Time appeared |
Debian
Debian debian Linux |
|
| CPEs | cpe:2.3:o:debian:debian_linux:10.0:*:*:*:*:*:*:* cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:* cpe:2.3:o:linux:linux_kernel:6.8:rc1:*:*:*:*:*:* cpe:2.3:o:linux:linux_kernel:6.8:rc2:*:*:*:*:*:* cpe:2.3:o:linux:linux_kernel:6.8:rc3:*:*:*:*:*:* cpe:2.3:o:linux:linux_kernel:6.8:rc4:*:*:*:*:*:* cpe:2.3:o:linux:linux_kernel:6.8:rc5:*:*:*:*:*:* |
|
| Vendors & Products |
Debian
Debian debian Linux |
Tue, 28 Jan 2025 17:15:00 +0000
| Type | Values Removed | Values Added |
|---|---|---|
| Metrics |
ssvc
|
ssvc
|
Fri, 22 Nov 2024 12:00:00 +0000
| Type | Values Removed | Values Added |
|---|---|---|
| References |
|
Wed, 06 Nov 2024 08:15:00 +0000
| Type | Values Removed | Values Added |
|---|---|---|
| First Time appeared |
Linux
Linux linux Kernel |
|
| CPEs | cpe:2.3:a:linux:linux_kernel:-:*:*:*:*:*:*:* cpe:2.3:o:linux:linux_kernel:-:*:*:*:*:*:*:* |
|
| Vendors & Products |
Linux
Linux linux Kernel |
|
| References |
|
|
| Metrics |
ssvc
|
MITRE
Status: PUBLISHED
Assigner: Linux
Published:
Updated: 2025-05-04T09:04:24.877Z
Reserved: 2024-02-25T13:47:42.681Z
Link: CVE-2024-27405
Vulnrichment
Updated: 2024-08-02T00:34:52.278Z
NVD
Status : Analyzed
Published: 2024-05-17T12:15:10.500
Modified: 2025-04-08T15:53:55.357
Link: CVE-2024-27405
Redhat
OpenCVE Enrichment
No data.
Weaknesses