| 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-2024-36478: null_blk: fix null-ptr-dereference while configuring 'power' and 'submit_queues' |
| |
| Description |
| =========== |
| |
| In the Linux kernel, the following vulnerability has been resolved: |
| |
| null_blk: fix null-ptr-dereference while configuring 'power' and 'submit_queues' |
| |
| Writing 'power' and 'submit_queues' concurrently will trigger kernel |
| panic: |
| |
| Test script: |
| |
| modprobe null_blk nr_devices=0 |
| mkdir -p /sys/kernel/config/nullb/nullb0 |
| while true; do echo 1 > submit_queues; echo 4 > submit_queues; done & |
| while true; do echo 1 > power; echo 0 > power; done |
| |
| Test result: |
| |
| BUG: kernel NULL pointer dereference, address: 0000000000000148 |
| Oops: 0000 [#1] PREEMPT SMP |
| RIP: 0010:__lock_acquire+0x41d/0x28f0 |
| Call Trace: |
| <TASK> |
| lock_acquire+0x121/0x450 |
| down_write+0x5f/0x1d0 |
| simple_recursive_removal+0x12f/0x5c0 |
| blk_mq_debugfs_unregister_hctxs+0x7c/0x100 |
| blk_mq_update_nr_hw_queues+0x4a3/0x720 |
| nullb_update_nr_hw_queues+0x71/0xf0 [null_blk] |
| nullb_device_submit_queues_store+0x79/0xf0 [null_blk] |
| configfs_write_iter+0x119/0x1e0 |
| vfs_write+0x326/0x730 |
| ksys_write+0x74/0x150 |
| |
| This is because del_gendisk() can concurrent with |
| blk_mq_update_nr_hw_queues(): |
| |
| nullb_device_power_store nullb_apply_submit_queues |
| null_del_dev |
| del_gendisk |
| nullb_update_nr_hw_queues |
| if (!dev->nullb) |
| // still set while gendisk is deleted |
| return 0 |
| blk_mq_update_nr_hw_queues |
| dev->nullb = NULL |
| |
| Fix this problem by resuing the global mutex to protect |
| nullb_device_power_store() and nullb_update_nr_hw_queues() from configfs. |
| |
| The Linux kernel CVE team has assigned CVE-2024-36478 to this issue. |
| |
| |
| Affected and fixed versions |
| =========================== |
| |
| Issue introduced in 5.5 with commit 45919fbfe1c487c17ea1d198534339a5e8abeae3 and fixed in 6.1.119 with commit 1d4c8baef435c98e8d5aa7027dc5a9f70834ba16 |
| Issue introduced in 5.5 with commit 45919fbfe1c487c17ea1d198534339a5e8abeae3 and fixed in 6.6.55 with commit aaadb755f2d684f715a6eb85cb7243aa0c67dfa9 |
| Issue introduced in 5.5 with commit 45919fbfe1c487c17ea1d198534339a5e8abeae3 and fixed in 6.9.4 with commit 5d0495473ee4c1d041b5a917f10446a22c047f47 |
| Issue introduced in 5.5 with commit 45919fbfe1c487c17ea1d198534339a5e8abeae3 and fixed in 6.10 with commit a2db328b0839312c169eb42746ec46fc1ab53ed2 |
| |
| 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-2024-36478 |
| 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/block/null_blk/main.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/1d4c8baef435c98e8d5aa7027dc5a9f70834ba16 |
| https://git.kernel.org/stable/c/aaadb755f2d684f715a6eb85cb7243aa0c67dfa9 |
| https://git.kernel.org/stable/c/5d0495473ee4c1d041b5a917f10446a22c047f47 |
| https://git.kernel.org/stable/c/a2db328b0839312c169eb42746ec46fc1ab53ed2 |
