CVE-2022-49526 Detail
Awaiting Analysis
This CVE record has been marked for NVD enrichment efforts. DescriptionIn the Linux kernel, the following vulnerability has been resolved: md/bitmap: don't set sb values if can't pass sanity check If bitmap area contains invalid data, kernel will crash then mdadm triggers "Segmentation fault". This is cluster-md speical bug. In non-clustered env, mdadm will handle broken metadata case. In clustered array, only kernel space handles bitmap slot info. But even this bug only happened in clustered env, current sanity check is wrong, the code should be changed. How to trigger: (faulty injection) dd if=/dev/zero bs=1M count=1 oflag=direct of=/dev/sda dd if=/dev/zero bs=1M count=1 oflag=direct of=/dev/sdb mdadm -C /dev/md0 -b clustered -e 1.2 -n 2 -l mirror /dev/sda /dev/sdb mdadm -Ss echo aaa > magic.txt == below modifying slot 2 bitmap data == dd if=magic.txt of=/dev/sda seek=16384 bs=1 count=3 <== destroy magic dd if=/dev/zero of=/dev/sda seek=16436 bs=1 count=4 <== ZERO chunksize mdadm -A /dev/md0 /dev/sda /dev/sdb == kernel crashes. mdadm outputs "Segmentation fault" == Reason of kernel crash: In md_bitmap_read_sb (called by md_bitmap_create), bad bitmap magic didn't block chunksize assignment, and zero value made DIV_ROUND_UP_SECTOR_T() trigger "divide error". Crash log: kernel: md: md0 stopped. kernel: md/raid1:md0: not clean -- starting background reconstruction kernel: md/raid1:md0: active with 2 out of 2 mirrors kernel: dlm: ... ... kernel: md-cluster: Joined cluster 44810aba-38bb-e6b8-daca-bc97a0b254aa slot 1 kernel: md0: invalid bitmap file superblock: bad magic kernel: md_bitmap_copy_from_slot can't get bitmap from slot 2 kernel: md-cluster: Could not gather bitmaps from slot 2 kernel: divide error: 0000 [#1] SMP NOPTI kernel: CPU: 0 PID: 1603 Comm: mdadm Not tainted 5.14.6-1-default kernel: Hardware name: QEMU Standard PC (i440FX + PIIX, 1996) kernel: RIP: 0010:md_bitmap_create+0x1d1/0x850 [md_mod] kernel: RSP: 0018:ffffc22ac0843ba0 EFLAGS: 00010246 kernel: ... ... kernel: Call Trace: kernel: ? dlm_lock_sync+0xd0/0xd0 [md_cluster 77fe..7a0] kernel: md_bitmap_copy_from_slot+0x2c/0x290 [md_mod 24ea..d3a] kernel: load_bitmaps+0xec/0x210 [md_cluster 77fe..7a0] kernel: md_bitmap_load+0x81/0x1e0 [md_mod 24ea..d3a] kernel: do_md_run+0x30/0x100 [md_mod 24ea..d3a] kernel: md_ioctl+0x1290/0x15a0 [md_mod 24ea....d3a] kernel: ? mddev_unlock+0xaa/0x130 [md_mod 24ea..d3a] kernel: ? blkdev_ioctl+0xb1/0x2b0 kernel: block_ioctl+0x3b/0x40 kernel: __x64_sys_ioctl+0x7f/0xb0 kernel: do_syscall_64+0x59/0x80 kernel: ? exit_to_user_mode_prepare+0x1ab/0x230 kernel: ? syscall_exit_to_user_mode+0x18/0x40 kernel: ? do_syscall_64+0x69/0x80 kernel: entry_SYSCALL_64_after_hwframe+0x44/0xae kernel: RIP: 0033:0x7f4a15fa722b kernel: ... ... kernel: ---[ end trace 8afa7612f559c868 ]--- kernel: RIP: 0010:md_bitmap_create+0x1d1/0x850 [md_mod] Metrics
NVD enrichment efforts reference publicly available information to associate
vector strings. CVSS information contributed by other sources is also
displayed.
CVSS 4.0 Severity and Vector Strings:
References to Advisories, Solutions, and ToolsBy selecting these links, you will be leaving NIST webspace. We have provided these links to other web sites because they may have information that would be of interest to you. No inferences should be drawn on account of other sites being referenced, or not, from this page. There may be other web sites that are more appropriate for your purpose. NIST does not necessarily endorse the views expressed, or concur with the facts presented on these sites. Further, NIST does not endorse any commercial products that may be mentioned on these sites. Please address comments about this page to nvd@nist.gov. Weakness Enumeration
Quick InfoCVE Dictionary Entry:CVE-2022-49526 NVD Published Date: 02/26/2025 NVD Last Modified: 02/26/2025 Source: kernel.org |