CVE-2022-49075

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Source
https://nvd.nist.gov/vuln/detail/CVE-2022-49075
Import Source
https://storage.googleapis.com/cve-osv-conversion/osv-output/CVE-2022-49075.json
JSON Data
https://api.osv.dev/v1/vulns/CVE-2022-49075
Related
Published
2025-02-26T07:00:44Z
Modified
2025-02-26T19:00:56.069395Z
Downstream
Summary
[none]
Details

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

btrfs: fix qgroup reserve overflow the qgroup limit

We use extentchangeset->byteschanged in qgroupreservedata() to record how many bytes we set for EXTENTQGROUPRESERVED state. Currently the bytes_changed is set as "unsigned int", and it will overflow if we try to fallocate a range larger than 4GiB. The result is we reserve less bytes and eventually break the qgroup limit.

Unlike regular buffered/direct write, which we use one changeset for each ordered extent, which can never be larger than 256M. For fallocate, we use one changeset for the whole range, thus it no longer respects the 256M per extent limit, and caused the problem.

The following example test script reproduces the problem:

$ cat qgroup-overflow.sh #!/bin/bash

DEV=/dev/sdj MNT=/mnt/sdj

mkfs.btrfs -f $DEV mount $DEV $MNT

# Set qgroup limit to 2GiB. btrfs quota enable $MNT btrfs qgroup limit 2G $MNT

# Try to fallocate a 3GiB file. This should fail. echo echo "Try to fallocate a 3GiB file..." fallocate -l 3G $MNT/3G.file

# Try to fallocate a 5GiB file. echo echo "Try to fallocate a 5GiB file..." fallocate -l 5G $MNT/5G.file

# See we break the qgroup limit. echo sync btrfs qgroup show -r $MNT

umount $MNT

When running the test:

$ ./qgroup-overflow.sh (...)

Try to fallocate a 3GiB file... fallocate: fallocate failed: Disk quota exceeded

Try to fallocate a 5GiB file...

qgroupid         rfer         excl     max_rfer --------         ----         ----     -------- 0/5           5.00GiB      5.00GiB      2.00GiB

Since we have no control of how bytes_changed is used, it's better to set it to u64.

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
5.10.113-1

Affected versions

5.*

5.10.46-4
5.10.46-5
5.10.70-1~bpo10+1
5.10.70-1
5.10.84-1
5.10.92-1~bpo10+1
5.10.92-1
5.10.92-2
5.10.103-1~bpo10+1
5.10.103-1
5.10.106-1

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
5.17.3-1

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
5.17.3-1

Ecosystem specific 

{
    "urgency": "not yet assigned"
}