CVE-2024-35979 Affecting kernel-debug package, versions <0:5.14.0-503.11.1.el9_5
Threat Intelligence
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Test your applications- Snyk IDSNYK-ORACLE9-KERNELDEBUG-8399236
- published20 Nov 2024
- disclosed20 May 2024
Introduced: 20 May 2024
CVE-2024-35979 (opens in a new tab)How to fix?
Upgrade Oracle:9 kernel-debug to version 0:5.14.0-503.11.1.el9_5 or higher.
This issue was patched in ELSA-2024-9315.
NVD Description
Note: Versions mentioned in the description apply only to the upstream kernel-debug package and not the kernel-debug package as distributed by Oracle.
See How to fix? for Oracle:9 relevant fixed versions and status.
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.
References
- https://linux.oracle.com/cve/CVE-2024-35979.html
- https://linux.oracle.com/errata/ELSA-2024-9315.html
- https://git.kernel.org/stable/c/3f28d49a328fe20926995d5fbdc92da665596268
- https://git.kernel.org/stable/c/f423f41b7679c09abb26d2bd54be5cbef23c9446
- https://git.kernel.org/stable/c/fcf3f7e2fc8a53a6140beee46ec782a4c88e4744