Hi Greg, FYI, I don't think this patch fixes a security issue. If attackers can corrupt a filesystem, then they should already be able to harm the whole system.
The commit description might be a bit confusing, but from an access control point of view, the filesystem on which we spotted this issue (bcachefs) does not allow to open weird files (but they are still visible, hence this patch) and I guess it would be the same for other filesystems, right? I'm not sure how a weird file could be used by user space. See https://lore.kernel.org/all/zpc46heaci%[email protected]/ The goal of this fix was mainly to not warn about a bcachefs issue (and avoid related syzkaller report for Landlock), and to harden Landlock in case other filesystems have this kind of bug. Anyway, always good to backport such fix. Regards, Mickaël On Thu, Mar 06, 2025 at 05:08:13PM +0100, Greg Kroah-Hartman wrote: > Description > =========== > > In the Linux kernel, the following vulnerability has been resolved: > > landlock: Handle weird files > > A corrupted filesystem (e.g. bcachefs) might return weird files. > Instead of throwing a warning and allowing access to such file, treat > them as regular files. > > The Linux kernel CVE team has assigned CVE-2025-21830 to this issue. > > > Affected and fixed versions > =========================== > > Issue introduced in 5.13 with commit > cb2c7d1a1776057c9a1f48ed1250d85e94d4850d and fixed in 6.1.129 with commit > 7d6121228959ddf44a4b9b6a177384ac7854e2f9 > Issue introduced in 5.13 with commit > cb2c7d1a1776057c9a1f48ed1250d85e94d4850d and fixed in 6.6.76 with commit > 39bb3d56f1c351e76bb18895d0e73796e653d5c1 > Issue introduced in 5.13 with commit > cb2c7d1a1776057c9a1f48ed1250d85e94d4850d and fixed in 6.12.13 with commit > 2569e65d2eb6ac1afe6cb6dfae476afee8b6771a > Issue introduced in 5.13 with commit > cb2c7d1a1776057c9a1f48ed1250d85e94d4850d and fixed in 6.13.2 with commit > 0fde195a373ab1267e60baa9e1a703a97e7464cd > Issue introduced in 5.13 with commit > cb2c7d1a1776057c9a1f48ed1250d85e94d4850d and fixed in 6.14-rc1 with commit > 49440290a0935f428a1e43a5ac8dc275a647ff80 > > 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-2025-21830 > 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: > security/landlock/fs.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/7d6121228959ddf44a4b9b6a177384ac7854e2f9 > https://git.kernel.org/stable/c/39bb3d56f1c351e76bb18895d0e73796e653d5c1 > https://git.kernel.org/stable/c/2569e65d2eb6ac1afe6cb6dfae476afee8b6771a > https://git.kernel.org/stable/c/0fde195a373ab1267e60baa9e1a703a97e7464cd > https://git.kernel.org/stable/c/49440290a0935f428a1e43a5ac8dc275a647ff80
