CVE-2022-49075
btrfs: fix qgroup reserve overflow the qgroup limit
- Published
- Updated
- Reserved
- Assigned by
- Linux
Description
In the Linux kernel, the following vulnerability has been resolved: btrfs: fix qgroup reserve overflow the qgroup limit We use extent_changeset->bytes_changed in qgroup_reserve_data() to record how many bytes we set for EXTENT_QGROUP_RESERVED 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.
Scores
| Scored by | CVSS | Score | Vector |
|---|---|---|---|
| LinuxCNA (assigner) | 3.1 | High8.1 | CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:N/I:H/A:H |
| NVDNVD · Modified | 3.1 | Medium5.5 | CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H |
- EPSS (exploitation in 30 days)
- 0.67% · top 48% of all CVEs (6 Nov 2026)
The list uses the assigner's score when there is one, then CISA's, then NVD's: High 8.1.
Weakness
Affected products
- affected 7bc329c1836866ffac8b2613f780a51b3ffe786d – < 0355387ea5b02d353c9415613fab908fac5c52a6
- affected 7bc329c1836866ffac8b2613f780a51b3ffe786d – < f3d97b22a708bf9e3f3ac2ba232bcefd0b0c136b
- affected 7bc329c1836866ffac8b2613f780a51b3ffe786d – < 44277c50fdba5019ca25bfad1b71e2561b0de11b
- affected 7bc329c1836866ffac8b2613f780a51b3ffe786d – < 82ae73ac963cee877ce34f7c31b2b456b516e96c
- affected 7bc329c1836866ffac8b2613f780a51b3ffe786d – < 4b98799e181b4326a613108cf37acc1f55d21b45
- affected 7bc329c1836866ffac8b2613f780a51b3ffe786d – < 6bfff81286d4491f02dad7814bae5c77c9ad2320
- affected 7bc329c1836866ffac8b2613f780a51b3ffe786d – < 7941b74ed49b6db25efbef2256ebef843c11a010
- affected 7bc329c1836866ffac8b2613f780a51b3ffe786d – < b642b52d0b50f4d398cb4293f64992d0eed2e2ce
- affected 4.13
- unaffected < 4.13
- unaffected 4.14.276 – ≤ 4.14.*
- unaffected 4.19.238 – ≤ 4.19.*
- unaffected 5.4.189 – ≤ 5.4.*
- unaffected 5.10.111 – ≤ 5.10.*
- unaffected 5.15.34 – ≤ 5.15.*
- unaffected 5.16.20 – ≤ 5.16.*
- unaffected 5.17.3 – ≤ 5.17.*
- unaffected 5.18 – ≤ *
References (8)
- https://git.kernel.org/stable/c/0355387ea5b02d353c9415613fab908fac5c52a6 (opens in a new tab)
- https://git.kernel.org/stable/c/f3d97b22a708bf9e3f3ac2ba232bcefd0b0c136b (opens in a new tab)
- https://git.kernel.org/stable/c/44277c50fdba5019ca25bfad1b71e2561b0de11b (opens in a new tab)
- https://git.kernel.org/stable/c/82ae73ac963cee877ce34f7c31b2b456b516e96c (opens in a new tab)
- https://git.kernel.org/stable/c/4b98799e181b4326a613108cf37acc1f55d21b45 (opens in a new tab)
- https://git.kernel.org/stable/c/6bfff81286d4491f02dad7814bae5c77c9ad2320 (opens in a new tab)
- https://git.kernel.org/stable/c/7941b74ed49b6db25efbef2256ebef843c11a010 (opens in a new tab)
- https://git.kernel.org/stable/c/b642b52d0b50f4d398cb4293f64992d0eed2e2ce (opens in a new tab)
Sources
The same CVE in the primary databases and aggregators, to check against.
- CVE.org record (opens in a new tab)
- CVE List JSON (GitHub) (opens in a new tab)
- NVD (opens in a new tab)
- FIRST EPSS (opens in a new tab)
- OSV.dev (opens in a new tab)
- GitHub Advisories (opens in a new tab)
- CIRCL Vulnerability-Lookup (opens in a new tab)
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[](https://trackcve.app/cve/CVE-2022-49075)Record last updated .