cve/2023/CVE-2023-52622.md

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2024-05-28 08:49:17 +00:00
### [CVE-2023-52622](https://cve.mitre.org/cgi-bin/cvename.cgi?name=CVE-2023-52622)
![](https://img.shields.io/static/v1?label=Product&message=Linux&color=blue)
![](https://img.shields.io/static/v1?label=Version&message=1da177e4c3f4%3C%20cd1f93ca97a9%20&color=brighgreen)
![](https://img.shields.io/static/v1?label=Vulnerability&message=n%2Fa&color=brighgreen)
### Description
In the Linux kernel, the following vulnerability has been resolved:ext4: avoid online resizing failures due to oversized flex bgWhen we online resize an ext4 filesystem with a oversized flexbg_size, mkfs.ext4 -F -G 67108864 $dev -b 4096 100M mount $dev $dir resize2fs $dev 16Gthe following WARN_ON is triggered:==================================================================WARNING: CPU: 0 PID: 427 at mm/page_alloc.c:4402 __alloc_pages+0x411/0x550Modules linked in: sg(E)CPU: 0 PID: 427 Comm: resize2fs Tainted: G E 6.6.0-rc5+ #314RIP: 0010:__alloc_pages+0x411/0x550Call Trace: <TASK> __kmalloc_large_node+0xa2/0x200 __kmalloc+0x16e/0x290 ext4_resize_fs+0x481/0xd80 __ext4_ioctl+0x1616/0x1d90 ext4_ioctl+0x12/0x20 __x64_sys_ioctl+0xf0/0x150 do_syscall_64+0x3b/0x90==================================================================This is because flexbg_size is too large and the size of the new_group_dataarray to be allocated exceeds MAX_ORDER. Currently, the minimum value ofMAX_ORDER is 8, the minimum value of PAGE_SIZE is 4096, the correspondingmaximum number of groups that can be allocated is: (PAGE_SIZE << MAX_ORDER) / sizeof(struct ext4_new_group_data) 21845And the value that is down-aligned to the power of 2 is 16384. Therefore,this value is defined as MAX_RESIZE_BG, and the number of groups addedeach time does not exceed this value during resizing, and is added multipletimes to complete the online resizing. The difference is that the metadatain a flex_bg may be more dispersed.
### POC
#### Reference
No PoCs from references.
#### Github
- https://github.com/fkie-cad/nvd-json-data-feeds