| 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-2021-47321: watchdog: Fix possible use-after-free by calling del_timer_sync() |
| |
| Description |
| =========== |
| |
| In the Linux kernel, the following vulnerability has been resolved: |
| |
| watchdog: Fix possible use-after-free by calling del_timer_sync() |
| |
| This driver's remove path calls del_timer(). However, that function |
| does not wait until the timer handler finishes. This means that the |
| timer handler may still be running after the driver's remove function |
| has finished, which would result in a use-after-free. |
| |
| Fix by calling del_timer_sync(), which makes sure the timer handler |
| has finished, and unable to re-schedule itself. |
| |
| The Linux kernel CVE team has assigned CVE-2021-47321 to this issue. |
| |
| |
| Affected and fixed versions |
| =========================== |
| |
| Fixed in 4.4.276 with commit 58606882ad8ec6c39e0f40344b922921ef94ab4d |
| Fixed in 4.9.276 with commit ca96b8ea5e74956071154bdb456778cc3027e79f |
| Fixed in 4.14.240 with commit 8bec568d7518b1504a602ed5376bb322e4dbb270 |
| Fixed in 4.19.198 with commit ecd620e0fb1ff7f78fdb593379b2e6938c99707a |
| Fixed in 5.4.134 with commit db222f1477ad5692cd454709b714949807e5d111 |
| Fixed in 5.10.52 with commit 66ba9cf929b1c4fabf545bd4c18f6f64e23e46e4 |
| Fixed in 5.12.19 with commit 4c05dac488a660fe2925c047ecb119e7afaaeb1e |
| Fixed in 5.13.4 with commit 1a053c4d716898a53c2e31c574a70ea0c37044a3 |
| Fixed in 5.14 with commit d0212f095ab56672f6f36aabc605bda205e1e0bf |
| |
| 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-2021-47321 |
| 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/watchdog/lpc18xx_wdt.c |
| drivers/watchdog/w83877f_wdt.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/58606882ad8ec6c39e0f40344b922921ef94ab4d |
| https://git.kernel.org/stable/c/ca96b8ea5e74956071154bdb456778cc3027e79f |
| https://git.kernel.org/stable/c/8bec568d7518b1504a602ed5376bb322e4dbb270 |
| https://git.kernel.org/stable/c/ecd620e0fb1ff7f78fdb593379b2e6938c99707a |
| https://git.kernel.org/stable/c/db222f1477ad5692cd454709b714949807e5d111 |
| https://git.kernel.org/stable/c/66ba9cf929b1c4fabf545bd4c18f6f64e23e46e4 |
| https://git.kernel.org/stable/c/4c05dac488a660fe2925c047ecb119e7afaaeb1e |
| https://git.kernel.org/stable/c/1a053c4d716898a53c2e31c574a70ea0c37044a3 |
| https://git.kernel.org/stable/c/d0212f095ab56672f6f36aabc605bda205e1e0bf |
