| 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-2024-26755: md: Don't suspend the array for interrupted reshape |
| |
| Description |
| =========== |
| |
| In the Linux kernel, the following vulnerability has been resolved: |
| |
| md: Don't suspend the array for interrupted reshape |
| |
| md_start_sync() will suspend the array if there are spares that can be |
| added or removed from conf, however, if reshape is still in progress, |
| this won't happen at all or data will be corrupted(remove_and_add_spares |
| won't be called from md_choose_sync_action for reshape), hence there is |
| no need to suspend the array if reshape is not done yet. |
| |
| Meanwhile, there is a potential deadlock for raid456: |
| |
| 1) reshape is interrupted; |
| |
| 2) set one of the disk WantReplacement, and add a new disk to the array, |
| however, recovery won't start until the reshape is finished; |
| |
| 3) then issue an IO across reshpae position, this IO will wait for |
| reshape to make progress; |
| |
| 4) continue to reshape, then md_start_sync() found there is a spare disk |
| that can be added to conf, mddev_suspend() is called; |
| |
| Step 4 and step 3 is waiting for each other, deadlock triggered. Noted |
| this problem is found by code review, and it's not reporduced yet. |
| |
| Fix this porblem by don't suspend the array for interrupted reshape, |
| this is safe because conf won't be changed until reshape is done. |
| |
| The Linux kernel CVE team has assigned CVE-2024-26755 to this issue. |
| |
| |
| Affected and fixed versions |
| =========================== |
| |
| Issue introduced in 6.7 with commit bc08041b32abe6c9824f78735bac22018eabfc06 and fixed in 6.7.7 with commit 60d6130d0ac1d883ed93c2a1e10aadb60967fd48 |
| Issue introduced in 6.7 with commit bc08041b32abe6c9824f78735bac22018eabfc06 and fixed in 6.8 with commit 9e46c70e829bddc24e04f963471e9983a11598b7 |
| |
| 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-2024-26755 |
| 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/md/md.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/60d6130d0ac1d883ed93c2a1e10aadb60967fd48 |
| https://git.kernel.org/stable/c/9e46c70e829bddc24e04f963471e9983a11598b7 |
