| 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-2024-35979: raid1: fix use-after-free for original bio in raid1_write_request() |
| |
| Description |
| =========== |
| |
| In the Linux kernel, the following vulnerability has been resolved: |
| |
| raid1: fix use-after-free for original bio in raid1_write_request() |
| |
| r1_bio->bios[] is used to record new bios that will be issued to |
| underlying disks, however, in raid1_write_request(), r1_bio->bios[] |
| will set to the original bio temporarily. Meanwhile, if blocked rdev |
| is set, free_r1bio() will be called causing that all r1_bio->bios[] |
| to be freed: |
| |
| raid1_write_request() |
| r1_bio = alloc_r1bio(mddev, bio); -> r1_bio->bios[] is NULL |
| for (i = 0; i < disks; i++) -> for each rdev in conf |
| // first rdev is normal |
| r1_bio->bios[0] = bio; -> set to original bio |
| // second rdev is blocked |
| if (test_bit(Blocked, &rdev->flags)) |
| break |
| |
| if (blocked_rdev) |
| free_r1bio() |
| put_all_bios() |
| bio_put(r1_bio->bios[0]) -> original bio is freed |
| |
| Test scripts: |
| |
| mdadm -CR /dev/md0 -l1 -n4 /dev/sd[abcd] --assume-clean |
| fio -filename=/dev/md0 -ioengine=libaio -rw=write -bs=4k -numjobs=1 \ |
| -iodepth=128 -name=test -direct=1 |
| echo blocked > /sys/block/md0/md/rd2/state |
| |
| Test result: |
| |
| BUG bio-264 (Not tainted): Object already free |
| ----------------------------------------------------------------------------- |
| |
| Allocated in mempool_alloc_slab+0x24/0x50 age=1 cpu=1 pid=869 |
| kmem_cache_alloc+0x324/0x480 |
| mempool_alloc_slab+0x24/0x50 |
| mempool_alloc+0x6e/0x220 |
| bio_alloc_bioset+0x1af/0x4d0 |
| blkdev_direct_IO+0x164/0x8a0 |
| blkdev_write_iter+0x309/0x440 |
| aio_write+0x139/0x2f0 |
| io_submit_one+0x5ca/0xb70 |
| __do_sys_io_submit+0x86/0x270 |
| __x64_sys_io_submit+0x22/0x30 |
| do_syscall_64+0xb1/0x210 |
| entry_SYSCALL_64_after_hwframe+0x6c/0x74 |
| Freed in mempool_free_slab+0x1f/0x30 age=1 cpu=1 pid=869 |
| kmem_cache_free+0x28c/0x550 |
| mempool_free_slab+0x1f/0x30 |
| mempool_free+0x40/0x100 |
| bio_free+0x59/0x80 |
| bio_put+0xf0/0x220 |
| free_r1bio+0x74/0xb0 |
| raid1_make_request+0xadf/0x1150 |
| md_handle_request+0xc7/0x3b0 |
| md_submit_bio+0x76/0x130 |
| __submit_bio+0xd8/0x1d0 |
| submit_bio_noacct_nocheck+0x1eb/0x5c0 |
| submit_bio_noacct+0x169/0xd40 |
| submit_bio+0xee/0x1d0 |
| blkdev_direct_IO+0x322/0x8a0 |
| blkdev_write_iter+0x309/0x440 |
| aio_write+0x139/0x2f0 |
| |
| Since that bios for underlying disks are not allocated yet, fix this |
| problem by using mempool_free() directly to free the r1_bio. |
| |
| The Linux kernel CVE team has assigned CVE-2024-35979 to this issue. |
| |
| |
| Affected and fixed versions |
| =========================== |
| |
| Issue introduced in 6.6 with commit 992db13a4aee766c8bfbf046ad15c2db5fa7cab8 and fixed in 6.6.28 with commit 3f28d49a328fe20926995d5fbdc92da665596268 |
| Issue introduced in 6.6 with commit 992db13a4aee766c8bfbf046ad15c2db5fa7cab8 and fixed in 6.8.7 with commit f423f41b7679c09abb26d2bd54be5cbef23c9446 |
| Issue introduced in 6.6 with commit 992db13a4aee766c8bfbf046ad15c2db5fa7cab8 and fixed in 6.9 with commit fcf3f7e2fc8a53a6140beee46ec782a4c88e4744 |
| |
| 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-2024-35979 |
| 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/raid1.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/3f28d49a328fe20926995d5fbdc92da665596268 |
| https://git.kernel.org/stable/c/f423f41b7679c09abb26d2bd54be5cbef23c9446 |
| https://git.kernel.org/stable/c/fcf3f7e2fc8a53a6140beee46ec782a4c88e4744 |
