| 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-2022-48812: net: dsa: lantiq_gswip: don't use devres for mdiobus |
| |
| Description |
| =========== |
| |
| In the Linux kernel, the following vulnerability has been resolved: |
| |
| net: dsa: lantiq_gswip: don't use devres for mdiobus |
| |
| 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 GSWIP switch is a platform 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 GSWIP 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 gswip driver has the code structure in place for orderly mdiobus |
| removal, so just replace devm_mdiobus_alloc() with the non-devres |
| variant, and add manual free where necessary, to ensure that we don't |
| let devres free a still-registered bus. |
| |
| The Linux kernel CVE team has assigned CVE-2022-48812 to this issue. |
| |
| |
| Affected and fixed versions |
| =========================== |
| |
| Issue introduced in 5.9 with commit ac3a68d56651c3dad2c12c7afce065fe15267f44 and fixed in 5.10.101 with commit e177d2e85ebcd3008c4b2abc293f4118e04eedef |
| Issue introduced in 5.9 with commit ac3a68d56651c3dad2c12c7afce065fe15267f44 and fixed in 5.15.24 with commit b5652bc50dde7b84e93dfb25479b64b817e377c1 |
| Issue introduced in 5.9 with commit ac3a68d56651c3dad2c12c7afce065fe15267f44 and fixed in 5.16.10 with commit 2443ba2fe396bdde187a2fdfa6a57375643ae93c |
| Issue introduced in 5.9 with commit ac3a68d56651c3dad2c12c7afce065fe15267f44 and fixed in 5.17 with commit 0d120dfb5d67edc5bcd1804e167dba2b30809afd |
| |
| 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-2022-48812 |
| 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/lantiq_gswip.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/e177d2e85ebcd3008c4b2abc293f4118e04eedef |
| https://git.kernel.org/stable/c/b5652bc50dde7b84e93dfb25479b64b817e377c1 |
| https://git.kernel.org/stable/c/2443ba2fe396bdde187a2fdfa6a57375643ae93c |
| https://git.kernel.org/stable/c/0d120dfb5d67edc5bcd1804e167dba2b30809afd |
