CVE-2024-27405
Assigner: Linux
Published: 2024-05-17T11:40:25.069Z
State: PUBLISHED
descriptions: value: 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.
affected: product: Linux
vendor: Linux
defaultStatus: unaffected
repo: https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git
versions: version: 9f6ce4240a2b
lessThan: 059285e04ebb
status: affected
versionType: git
version: 9f6ce4240a2b
lessThan: a31cf46d108d
status: affected
versionType: git
version: 9f6ce4240a2b
lessThan: 57ca0e16f393
status: affected
versionType: git
version: 9f6ce4240a2b
lessThan: 2cb66b62a5d6
status: affected
versionType: git
version: 9f6ce4240a2b
lessThan: 35b604a37ec7
status: affected
versionType: git
version: 9f6ce4240a2b
lessThan: 2b7ec68869d5
status: affected
versionType: git
version: 9f6ce4240a2b
lessThan: c7f43900bc72
status: affected
versionType: git
version: 9f6ce4240a2b
lessThan: 76c51146820c
status: affected
versionType: git
product: Linux
vendor: Linux
defaultStatus: affected
repo: https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git
versions: version: 2.6.38
status: affected
version: 0
lessThan: 2.6.38
status: unaffected
versionType: custom
version: 4.19.308
lessThanOrEqual: 4.19.*
status: unaffected
versionType: custom
version: 5.4.270
lessThanOrEqual: 5.4.*
status: unaffected
versionType: custom
version: 5.10.211
lessThanOrEqual: 5.10.*
status: unaffected
versionType: custom
version: 5.15.150
lessThanOrEqual: 5.15.*
status: unaffected
versionType: custom
version: 6.1.80
lessThanOrEqual: 6.1.*
status: unaffected
versionType: custom
version: 6.6.19
lessThanOrEqual: 6.6.*
status: unaffected
versionType: custom
version: 6.7.7
lessThanOrEqual: 6.7.*
status: unaffected
versionType: custom
version: 6.8
lessThanOrEqual: *
status: unaffected
versionType: original_commit_for_fix
title: usb: gadget: ncm: Avoid dropping datagrams of properly parsed NTBs
x_generator: engine: bippy-d175d3acf727