CVE - CVE-2022-48733

CVE-ID
CVE-2022-48733	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 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.
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/28b21c558a3753171097193b6f6602a94169093a URL:https://git.kernel.org/stable/c/28b21c558a3753171097193b6f6602a94169093a MISC:https://git.kernel.org/stable/c/7e4c72dbaf62f8978af8321a24dbd35566d3a78a URL:https://git.kernel.org/stable/c/7e4c72dbaf62f8978af8321a24dbd35566d3a78a MISC:https://git.kernel.org/stable/c/9372fa1d73da5f1673921e365d0cd2c27ec7adc2 URL:https://git.kernel.org/stable/c/9372fa1d73da5f1673921e365d0cd2c27ec7adc2 MISC:https://git.kernel.org/stable/c/a7b717fa15165d3d9245614680bebc48a52ac05d URL:https://git.kernel.org/stable/c/a7b717fa15165d3d9245614680bebc48a52ac05d
Assigning CNA
kernel.org
Date Record Created
20240620	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 (20240620)
Votes (Legacy)

Comments (Legacy)

Proposed (Legacy)
N/A
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