| From bippy-5f407fcff5a0 Mon Sep 17 00:00:00 2001 |
| From: Greg Kroah-Hartman <gregkh@linuxfoundation.org> |
| To: <linux-cve-announce@vger.kernel.org> |
| Reply-to: <cve@kernel.org>, <linux-kernel@vger.kernel.org> |
| Subject: CVE-2025-21879: btrfs: fix use-after-free on inode when scanning root during em shrinking |
| |
| Description |
| =========== |
| |
| In the Linux kernel, the following vulnerability has been resolved: |
| |
| btrfs: fix use-after-free on inode when scanning root during em shrinking |
| |
| At btrfs_scan_root() we are accessing the inode's root (and fs_info) in a |
| call to btrfs_fs_closing() after we have scheduled the inode for a delayed |
| iput, and that can result in a use-after-free on the inode in case the |
| cleaner kthread does the iput before we dereference the inode in the call |
| to btrfs_fs_closing(). |
| |
| Fix this by using the fs_info stored already in a local variable instead |
| of doing inode->root->fs_info. |
| |
| The Linux kernel CVE team has assigned CVE-2025-21879 to this issue. |
| |
| |
| Affected and fixed versions |
| =========================== |
| |
| Issue introduced in 6.13 with commit 1020443840569535f6025a855958f07ea3eebf71 and fixed in 6.13.6 with commit 5e79d26014f9386387575b9ed60d342057cee49b |
| Issue introduced in 6.13 with commit 1020443840569535f6025a855958f07ea3eebf71 and fixed in 6.14 with commit 59f37036bb7ab3d554c24abc856aabca01126414 |
| |
| Please see https://www.kernel.org for a full list of currently supported |
| kernel versions by the kernel community. |
| |
| Unaffected versions might change over time as fixes are backported to |
| older supported kernel versions. The official CVE entry at |
| https://cve.org/CVERecord/?id=CVE-2025-21879 |
| will be updated if fixes are backported, please check that for the most |
| up to date information about this issue. |
| |
| |
| Affected files |
| ============== |
| |
| The file(s) affected by this issue are: |
| fs/btrfs/extent_map.c |
| |
| |
| Mitigation |
| ========== |
| |
| The Linux kernel CVE team recommends that you update to the latest |
| stable kernel version for this, and many other bugfixes. Individual |
| changes are never tested alone, but rather are part of a larger kernel |
| release. Cherry-picking individual commits is not recommended or |
| supported by the Linux kernel community at all. If however, updating to |
| the latest release is impossible, the individual changes to resolve this |
| issue can be found at these commits: |
| https://git.kernel.org/stable/c/5e79d26014f9386387575b9ed60d342057cee49b |
| https://git.kernel.org/stable/c/59f37036bb7ab3d554c24abc856aabca01126414 |
