| 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-2022-48817: net: dsa: ar9331: register the mdiobus under devres |
| |
| Description |
| =========== |
| |
| In the Linux kernel, the following vulnerability has been resolved: |
| |
| net: dsa: ar9331: register the mdiobus under devres |
| |
| As explained in commits: |
| 74b6d7d13307 ("net: dsa: realtek: register the MDIO bus under devres") |
| 5135e96a3dd2 ("net: dsa: don't allocate the slave_mii_bus using devres") |
| |
| mdiobus_free() will panic when called from devm_mdiobus_free() <- |
| devres_release_all() <- __device_release_driver(), and that mdiobus was |
| not previously unregistered. |
| |
| The ar9331 is an MDIO device, so the initial set of constraints that I |
| thought would cause this (I2C or SPI buses which call ->remove on |
| ->shutdown) do not apply. But there is one more which applies here. |
| |
| If the DSA master itself is on a bus that calls ->remove from ->shutdown |
| (like dpaa2-eth, which is on the fsl-mc bus), there is a device link |
| between the switch and the DSA master, and device_links_unbind_consumers() |
| will unbind the ar9331 switch driver on shutdown. |
| |
| So the same treatment must be applied to all DSA switch drivers, which |
| is: either use devres for both the mdiobus allocation and registration, |
| or don't use devres at all. |
| |
| The ar9331 driver doesn't have a complex code structure for mdiobus |
| removal, so just replace of_mdiobus_register with the devres variant in |
| order to be all-devres and ensure that we don't free a still-registered |
| bus. |
| |
| The Linux kernel CVE team has assigned CVE-2022-48817 to this issue. |
| |
| |
| Affected and fixed versions |
| =========================== |
| |
| Issue introduced in 5.9 with commit ac3a68d56651c3dad2c12c7afce065fe15267f44 and fixed in 5.10.101 with commit 475ce5dcf2d88fd4f3c213a0ac944e3e40702970 |
| Issue introduced in 5.9 with commit ac3a68d56651c3dad2c12c7afce065fe15267f44 and fixed in 5.15.24 with commit aae1c6a1d3d696fc33b609fb12fe744a556d1dc5 |
| Issue introduced in 5.9 with commit ac3a68d56651c3dad2c12c7afce065fe15267f44 and fixed in 5.16.10 with commit f1842a8cb71de4d7eb75a86f76e88c7ee739218c |
| Issue introduced in 5.9 with commit ac3a68d56651c3dad2c12c7afce065fe15267f44 and fixed in 5.17 with commit 50facd86e9fbc4b93fe02e5fe05776047f45dbfb |
| |
| 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-2022-48817 |
| 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/net/dsa/qca/ar9331.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/475ce5dcf2d88fd4f3c213a0ac944e3e40702970 |
| https://git.kernel.org/stable/c/aae1c6a1d3d696fc33b609fb12fe744a556d1dc5 |
| https://git.kernel.org/stable/c/f1842a8cb71de4d7eb75a86f76e88c7ee739218c |
| https://git.kernel.org/stable/c/50facd86e9fbc4b93fe02e5fe05776047f45dbfb |
