| From bippy-1.2.0 Mon Sep 17 00:00:00 2001 |
| From: Greg Kroah-Hartman <gregkh@kernel.org> |
| To: <linux-cve-announce@vger.kernel.org> |
| Reply-to: <cve@kernel.org>, <linux-kernel@vger.kernel.org> |
| Subject: CVE-2025-22126: md: fix mddev uaf while iterating all_mddevs list |
| |
| Description |
| =========== |
| |
| In the Linux kernel, the following vulnerability has been resolved: |
| |
| md: fix mddev uaf while iterating all_mddevs list |
| |
| While iterating all_mddevs list from md_notify_reboot() and md_exit(), |
| list_for_each_entry_safe is used, and this can race with deletint the |
| next mddev, causing UAF: |
| |
| t1: |
| spin_lock |
| //list_for_each_entry_safe(mddev, n, ...) |
| mddev_get(mddev1) |
| // assume mddev2 is the next entry |
| spin_unlock |
| t2: |
| //remove mddev2 |
| ... |
| mddev_free |
| spin_lock |
| list_del |
| spin_unlock |
| kfree(mddev2) |
| mddev_put(mddev1) |
| spin_lock |
| //continue dereference mddev2->all_mddevs |
| |
| The old helper for_each_mddev() actually grab the reference of mddev2 |
| while holding the lock, to prevent from being freed. This problem can be |
| fixed the same way, however, the code will be complex. |
| |
| Hence switch to use list_for_each_entry, in this case mddev_put() can free |
| the mddev1 and it's not safe as well. Refer to md_seq_show(), also factor |
| out a helper mddev_put_locked() to fix this problem. |
| |
| The Linux kernel CVE team has assigned CVE-2025-22126 to this issue. |
| |
| |
| Affected and fixed versions |
| =========================== |
| |
| Issue introduced in 6.0 with commit f26514342255855f4ca3c0a92cb1cdea01c33004 and fixed in 6.1.135 with commit ca9f84de76723b358dfc0606668efdca54afc2e5 |
| Issue introduced in 6.0 with commit f26514342255855f4ca3c0a92cb1cdea01c33004 and fixed in 6.6.88 with commit d69a23d8e925f8052d657652a6875ec2712c7e33 |
| Issue introduced in 6.0 with commit f26514342255855f4ca3c0a92cb1cdea01c33004 and fixed in 6.12.25 with commit e2a9f73ee408a460f4c9dfe03b4741d6b11652b8 |
| Issue introduced in 6.0 with commit f26514342255855f4ca3c0a92cb1cdea01c33004 and fixed in 6.14.2 with commit 5462544ccbad3fc938a71b01fa5bd3a0dc2b750a |
| Issue introduced in 6.0 with commit f26514342255855f4ca3c0a92cb1cdea01c33004 and fixed in 6.15 with commit 8542870237c3a48ff049b6c5df5f50c8728284fa |
| |
| 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-2025-22126 |
| 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: |
| drivers/md/md.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/ca9f84de76723b358dfc0606668efdca54afc2e5 |
| https://git.kernel.org/stable/c/d69a23d8e925f8052d657652a6875ec2712c7e33 |
| https://git.kernel.org/stable/c/e2a9f73ee408a460f4c9dfe03b4741d6b11652b8 |
| https://git.kernel.org/stable/c/5462544ccbad3fc938a71b01fa5bd3a0dc2b750a |
| https://git.kernel.org/stable/c/8542870237c3a48ff049b6c5df5f50c8728284fa |
