Description

In the Linux kernel, the following vulnerability has been resolved: btrfs: fix use-after-free after failure to create a snapshot At ioctl.c:create_snapshot(), we allocate a pending snapshot structure and then attach it to the transaction's list of pending snapshots. After that we call btrfs_commit_transaction(), and if that returns an error we jump to 'fail' label, where we kfree() the pending snapshot structure. This can result in a later use-after-free of the pending snapshot: 1) We allocated the pending snapshot and added it to the transaction's list of pending snapshots; 2) We call btrfs_commit_transaction(), and it fails either at the first call to btrfs_run_delayed_refs() or btrfs_start_dirty_block_groups(). In both cases, we don't abort the transaction and we release our transaction handle. We jump to the 'fail' label and free the pending snapshot structure. We return with the pending snapshot still in the transaction's list; 3) Another task commits the transaction. This time there's no error at all, and then during the transaction commit it accesses a pointer to the pending snapshot structure that the snapshot creation task has already freed, resulting in a user-after-free. This issue could actually be detected by smatch, which produced the following warning: fs/btrfs/ioctl.c:843 create_snapshot() warn: '&pending_snapshot->list' not removed from list So fix this by not having the snapshot creation ioctl directly add the pending snapshot to the transaction's list. Instead add the pending snapshot to the transaction handle, and then at btrfs_commit_transaction() we add the snapshot to the list only when we can guarantee that any error returned after that point will result in a transaction abort, in which case the ioctl code can safely free the pending snapshot and no one can access it anymore.

Metrics

 

CVSS Version 4.0 CVSS Version 3.x CVSS Version 2.0

NVD enrichment efforts reference publicly available information to associate vector strings. CVSS information contributed by other sources is also displayed.

CVSS 4.0 Severity and Vector Strings:

NIST: NVD

N/A

NVD assessment not yet provided.

CVSS 3.x Severity and Vector Strings:

NIST: NVD

Base Score:  7.8 HIGH

Vector:  CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H

CVSS 2.0 Severity and Vector Strings:

NIST: NVD

Base Score: N/A

NVD assessment not yet provided.

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Hyperlink	Resource
https://git.kernel.org/stable/c/28b21c558a3753171097193b6f6602a94169093a	Patch
https://git.kernel.org/stable/c/7e4c72dbaf62f8978af8321a24dbd35566d3a78a
https://git.kernel.org/stable/c/9372fa1d73da5f1673921e365d0cd2c27ec7adc2	Patch
https://git.kernel.org/stable/c/a7b717fa15165d3d9245614680bebc48a52ac05d	Patch

Weakness Enumeration

CWE-ID	CWE Name	Source
CWE-416	Use After Free	NIST

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Change History

3 change records found show changes

CVE Modified by kernel.org 9/12/2024 8:15:46 AM

Action	Type	Old Value	New Value
Added	Reference		kernel.org https://git.kernel.org/stable/c/7e4c72dbaf62f8978af8321a24dbd35566d3a78a [No types assigned]

Initial Analysis by NIST 8/19/2024 1:39:17 PM

Action	Type	Old Value	New Value
Added	CPE Configuration		OR *cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:* versions up to (excluding) 5.15.22 *cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:* versions from (including) 5.16 up to (excluding) 5.16.8
Added	CVSS V3.1		NIST AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H
Added	CWE		NIST CWE-416
Changed	Reference Type	https://git.kernel.org/stable/c/28b21c558a3753171097193b6f6602a94169093a No Types Assigned	https://git.kernel.org/stable/c/28b21c558a3753171097193b6f6602a94169093a Patch
Changed	Reference Type	https://git.kernel.org/stable/c/9372fa1d73da5f1673921e365d0cd2c27ec7adc2 No Types Assigned	https://git.kernel.org/stable/c/9372fa1d73da5f1673921e365d0cd2c27ec7adc2 Patch
Changed	Reference Type	https://git.kernel.org/stable/c/a7b717fa15165d3d9245614680bebc48a52ac05d No Types Assigned	https://git.kernel.org/stable/c/a7b717fa15165d3d9245614680bebc48a52ac05d Patch

New CVE Received by NIST 6/20/2024 8:15:11 AM

Action	Type	Old Value	New Value
Added	Description		Record truncated, showing 500 of 1867 characters. View Entire Change Record In the Linux kernel, the following vulnerability has been resolved: btrfs: fix use-after-free after failure to create a snapshot At ioctl.c:create_snapshot(), we allocate a pending snapshot structure and then attach it to the transaction's list of pending snapshots. After that we call btrfs_commit_transaction(), and if that returns an error we jump to 'fail' label, where we kfree() the pending snapshot structure. This can result in a later use-after-free of the pending snapshot: 1) We allocat
Added	Reference		kernel.org https://git.kernel.org/stable/c/28b21c558a3753171097193b6f6602a94169093a [No types assigned]
Added	Reference		kernel.org https://git.kernel.org/stable/c/9372fa1d73da5f1673921e365d0cd2c27ec7adc2 [No types assigned]
Added	Reference		kernel.org https://git.kernel.org/stable/c/a7b717fa15165d3d9245614680bebc48a52ac05d [No types assigned]