CVE-2021-47267

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Source
https://nvd.nist.gov/vuln/detail/CVE-2021-47267
Import Source
https://storage.googleapis.com/cve-osv-conversion/osv-output/CVE-2021-47267.json
JSON Data
https://api.osv.dev/v1/vulns/CVE-2021-47267
Related
Published
2024-05-21T15:15:15Z
Modified
2024-09-18T01:00:20Z
Summary
[none]
Details

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

usb: fix various gadget panics on 10gbps cabling

usbassigndescriptors() is called with 5 parameters, the last 4 of which are the usbdescriptorheader for: full-speed (USB1.1 - 12Mbps [including USB1.0 low-speed @ 1.5Mbps), high-speed (USB2.0 - 480Mbps), super-speed (USB3.0 - 5Gbps), super-speed-plus (USB3.1 - 10Gbps).

The differences between full/high/super-speed descriptors are usually substantial (due to changes in the maximum usb block size from 64 to 512 to 1024 bytes and other differences in the specs), while the difference between 5 and 10Gbps descriptors may be as little as nothing (in many cases the same tuning is simply good enough).

However if a gadget driver calls usbassigndescriptors() with a NULL descriptor for super-speed-plus and is then used on a max 10gbps configuration, the kernel will crash with a null pointer dereference, when a 10gbps capable device port + cable + host port combination shows up. (This wouldn't happen if the gadget max-speed was set to 5gbps, but it of course defaults to the maximum, and there's no real reason to artificially limit it)

The fix is to simply use the 5gbps descriptor as the 10gbps descriptor, if a 10gbps descriptor wasn't provided.

Obviously this won't fix the problem if the 5gbps descriptor is also NULL, but such cases can't be so trivially solved (and any such gadgets are unlikely to be used with USB3 ports any way).

References

Affected packages

Debian:11 / linux

Package

Name
linux
Purl
pkg:deb/debian/linux?arch=source

Affected ranges

Type
ECOSYSTEM
Events
Introduced
0Unknown introduced version / All previous versions are affected
Fixed
5.10.46-1

Ecosystem specific

{
    "urgency": "not yet assigned"
}

Debian:12 / linux

Package

Name
linux
Purl
pkg:deb/debian/linux?arch=source

Affected ranges

Type
ECOSYSTEM
Events
Introduced
0Unknown introduced version / All previous versions are affected
Fixed
5.10.46-1

Ecosystem specific

{
    "urgency": "not yet assigned"
}

Debian:13 / linux

Package

Name
linux
Purl
pkg:deb/debian/linux?arch=source

Affected ranges

Type
ECOSYSTEM
Events
Introduced
0Unknown introduced version / All previous versions are affected
Fixed
5.10.46-1

Ecosystem specific

{
    "urgency": "not yet assigned"
}