From bippy-851b3ed3d212 Mon Sep 17 00:00:00 2001 From: Greg Kroah-Hartman To: Reply-to: , Subject: CVE-2021-47088: mm/damon/dbgfs: protect targets destructions with kdamond_lock Description =========== In the Linux kernel, the following vulnerability has been resolved: mm/damon/dbgfs: protect targets destructions with kdamond_lock DAMON debugfs interface iterates current monitoring targets in 'dbgfs_target_ids_read()' while holding the corresponding 'kdamond_lock'. However, it also destructs the monitoring targets in 'dbgfs_before_terminate()' without holding the lock. This can result in a use_after_free bug. This commit avoids the race by protecting the destruction with the corresponding 'kdamond_lock'. The Linux kernel CVE team has assigned CVE-2021-47088 to this issue. Affected and fixed versions =========================== Issue introduced in 5.15 with commit 4bc05954d007 and fixed in 5.15.12 with commit 330c6117a82c Issue introduced in 5.15 with commit 4bc05954d007 and fixed in 5.16 with commit 34796417964b 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-2021-47088 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: mm/damon/dbgfs.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/330c6117a82c16a9a365a51cec5c9ab30b13245c https://git.kernel.org/stable/c/34796417964b8d0aef45a99cf6c2d20cebe33733