| 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-2022-49406: block: Fix potential deadlock in blk_ia_range_sysfs_show() |
| |
| Description |
| =========== |
| |
| In the Linux kernel, the following vulnerability has been resolved: |
| |
| block: Fix potential deadlock in blk_ia_range_sysfs_show() |
| |
| When being read, a sysfs attribute is already protected against removal |
| with the kobject node active reference counter. As a result, in |
| blk_ia_range_sysfs_show(), there is no need to take the queue sysfs |
| lock when reading the value of a range attribute. Using the queue sysfs |
| lock in this function creates a potential deadlock situation with the |
| disk removal, something that a lockdep signals with a splat when the |
| device is removed: |
| |
| [ 760.703551] Possible unsafe locking scenario: |
| [ 760.703551] |
| [ 760.703554] CPU0 CPU1 |
| [ 760.703556] ---- ---- |
| [ 760.703558] lock(&q->sysfs_lock); |
| [ 760.703565] lock(kn->active#385); |
| [ 760.703573] lock(&q->sysfs_lock); |
| [ 760.703579] lock(kn->active#385); |
| [ 760.703587] |
| [ 760.703587] *** DEADLOCK *** |
| |
| Solve this by removing the mutex_lock()/mutex_unlock() calls from |
| blk_ia_range_sysfs_show(). |
| |
| The Linux kernel CVE team has assigned CVE-2022-49406 to this issue. |
| |
| |
| Affected and fixed versions |
| =========================== |
| |
| Issue introduced in 5.16 with commit a2247f19ee1c5ad75ef095cdfb909a3244b88aa8 and fixed in 5.17.14 with commit dc107c805cde709866b59867ef72b9390199205e |
| Issue introduced in 5.16 with commit a2247f19ee1c5ad75ef095cdfb909a3244b88aa8 and fixed in 5.18.3 with commit 717b078bc745ba9a262abebed9806a17e8bbb77b |
| Issue introduced in 5.16 with commit a2247f19ee1c5ad75ef095cdfb909a3244b88aa8 and fixed in 5.19 with commit 41e46b3c2aa24f755b2ae9ec4ce931ba5f0d8532 |
| |
| 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-2022-49406 |
| 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: |
| block/blk-ia-ranges.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/dc107c805cde709866b59867ef72b9390199205e |
| https://git.kernel.org/stable/c/717b078bc745ba9a262abebed9806a17e8bbb77b |
| https://git.kernel.org/stable/c/41e46b3c2aa24f755b2ae9ec4ce931ba5f0d8532 |
