| 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-2021-47439: net: dsa: microchip: Added the condition for scheduling ksz_mib_read_work |
| |
| Description |
| =========== |
| |
| In the Linux kernel, the following vulnerability has been resolved: |
| |
| net: dsa: microchip: Added the condition for scheduling ksz_mib_read_work |
| |
| When the ksz module is installed and removed using rmmod, kernel crashes |
| with null pointer dereferrence error. During rmmod, ksz_switch_remove |
| function tries to cancel the mib_read_workqueue using |
| cancel_delayed_work_sync routine and unregister switch from dsa. |
| |
| During dsa_unregister_switch it calls ksz_mac_link_down, which in turn |
| reschedules the workqueue since mib_interval is non-zero. |
| Due to which queue executed after mib_interval and it tries to access |
| dp->slave. But the slave is unregistered in the ksz_switch_remove |
| function. Hence kernel crashes. |
| |
| To avoid this crash, before canceling the workqueue, resetted the |
| mib_interval to 0. |
| |
| v1 -> v2: |
| -Removed the if condition in ksz_mib_read_work |
| |
| The Linux kernel CVE team has assigned CVE-2021-47439 to this issue. |
| |
| |
| Affected and fixed versions |
| =========================== |
| |
| Issue introduced in 5.7 with commit 469b390e1ba330e888175e55d78573db2e9a8cb4 and fixed in 5.10.75 with commit f2e1de075018cf71bcd7d628e9f759cb8540b0c3 |
| Issue introduced in 5.7 with commit 469b390e1ba330e888175e55d78573db2e9a8cb4 and fixed in 5.14.14 with commit 383239a33cf29ebee9ce0d4e0e5c900b77a16148 |
| Issue introduced in 5.7 with commit 469b390e1ba330e888175e55d78573db2e9a8cb4 and fixed in 5.15 with commit ef1100ef20f29aec4e62abeccdb5bdbebba1e378 |
| |
| 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-2021-47439 |
| 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/microchip/ksz_common.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/f2e1de075018cf71bcd7d628e9f759cb8540b0c3 |
| https://git.kernel.org/stable/c/383239a33cf29ebee9ce0d4e0e5c900b77a16148 |
| https://git.kernel.org/stable/c/ef1100ef20f29aec4e62abeccdb5bdbebba1e378 |
