CVE - CVE-2022-49075

CVE-ID
CVE-2022-49075	Learn more at National Vulnerability Database (NVD) • CVSS Severity Rating • Fix Information • Vulnerable Software Versions • SCAP Mappings • CPE Information
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.
References
Note: References are provided for the convenience of the reader to help distinguish between vulnerabilities. The list is not intended to be complete.
MISC:https://git.kernel.org/stable/c/0355387ea5b02d353c9415613fab908fac5c52a6 URL:https://git.kernel.org/stable/c/0355387ea5b02d353c9415613fab908fac5c52a6 MISC:https://git.kernel.org/stable/c/44277c50fdba5019ca25bfad1b71e2561b0de11b URL:https://git.kernel.org/stable/c/44277c50fdba5019ca25bfad1b71e2561b0de11b MISC:https://git.kernel.org/stable/c/4b98799e181b4326a613108cf37acc1f55d21b45 URL:https://git.kernel.org/stable/c/4b98799e181b4326a613108cf37acc1f55d21b45 MISC:https://git.kernel.org/stable/c/6bfff81286d4491f02dad7814bae5c77c9ad2320 URL:https://git.kernel.org/stable/c/6bfff81286d4491f02dad7814bae5c77c9ad2320 MISC:https://git.kernel.org/stable/c/7941b74ed49b6db25efbef2256ebef843c11a010 URL:https://git.kernel.org/stable/c/7941b74ed49b6db25efbef2256ebef843c11a010 MISC:https://git.kernel.org/stable/c/82ae73ac963cee877ce34f7c31b2b456b516e96c URL:https://git.kernel.org/stable/c/82ae73ac963cee877ce34f7c31b2b456b516e96c MISC:https://git.kernel.org/stable/c/b642b52d0b50f4d398cb4293f64992d0eed2e2ce URL:https://git.kernel.org/stable/c/b642b52d0b50f4d398cb4293f64992d0eed2e2ce MISC:https://git.kernel.org/stable/c/f3d97b22a708bf9e3f3ac2ba232bcefd0b0c136b URL:https://git.kernel.org/stable/c/f3d97b22a708bf9e3f3ac2ba232bcefd0b0c136b
Assigning CNA
kernel.org
Date Record Created
20250226	Disclaimer: The record creation date may reflect when the CVE ID was allocated or reserved, and does not necessarily indicate when this vulnerability was discovered, shared with the affected vendor, publicly disclosed, or updated in CVE.
Phase (Legacy)
Assigned (20250226)
Votes (Legacy)

Comments (Legacy)

Proposed (Legacy)
N/A
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