Bug 2390351 (CVE-2025-38652)

Summary: CVE-2025-38652 kernel: f2fs: fix to avoid out-of-boundary access in devs.path
Product: [Other] Security Response Reporter: OSIDB Bzimport <bzimport>
Component: vulnerabilityAssignee: Product Security DevOps Team <prodsec-dev>
Status: NEW --- QA Contact:
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Version: unspecifiedKeywords: Security
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Hardware: All   
OS: Linux   
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Description OSIDB Bzimport 2025-08-22 17:01:58 UTC
In the Linux kernel, the following vulnerability has been resolved:

f2fs: fix to avoid out-of-boundary access in devs.path

- touch /mnt/f2fs/012345678901234567890123456789012345678901234567890123
- truncate -s $((1024*1024*1024)) \
  /mnt/f2fs/012345678901234567890123456789012345678901234567890123
- touch /mnt/f2fs/file
- truncate -s $((1024*1024*1024)) /mnt/f2fs/file
- mkfs.f2fs /mnt/f2fs/012345678901234567890123456789012345678901234567890123 \
  -c /mnt/f2fs/file
- mount /mnt/f2fs/012345678901234567890123456789012345678901234567890123 \
  /mnt/f2fs/loop

[16937.192225] F2FS-fs (loop0): Mount Device [ 0]: /mnt/f2fs/012345678901234567890123456789012345678901234567890123\xff\x01,      511,        0 -    3ffff
[16937.192268] F2FS-fs (loop0): Failed to find devices

If device path length equals to MAX_PATH_LEN, sbi->devs.path[] may
not end up w/ null character due to path array is fully filled, So
accidently, fields locate after path[] may be treated as part of
device path, result in parsing wrong device path.

struct f2fs_dev_info {
...
	char path[MAX_PATH_LEN];
...
};

Let's add one byte space for sbi->devs.path[] to store null
character of device path string.