CVE-2022-50478
Unknown Unknown - Not Provided
BaseFortify

Publication date: 2025-10-04

Last updated on: 2025-10-06

Assigner: kernel.org

Description
In the Linux kernel, the following vulnerability has been resolved: nilfs2: fix shift-out-of-bounds/overflow in nilfs_sb2_bad_offset() Patch series "nilfs2: fix UBSAN shift-out-of-bounds warnings on mount time". The first patch fixes a bug reported by syzbot, and the second one fixes the remaining bug of the same kind. Although they are triggered by the same super block data anomaly, I divided it into the above two because the details of the issues and how to fix it are different. Both are required to eliminate the shift-out-of-bounds issues at mount time. This patch (of 2): If the block size exponent information written in an on-disk superblock is corrupted, nilfs_sb2_bad_offset helper function can trigger shift-out-of-bounds warning followed by a kernel panic (if panic_on_warn is set): shift exponent 38983 is too large for 64-bit type 'unsigned long long' Call Trace: <TASK> __dump_stack lib/dump_stack.c:88 [inline] dump_stack_lvl+0x1b1/0x28e lib/dump_stack.c:106 ubsan_epilogue lib/ubsan.c:151 [inline] __ubsan_handle_shift_out_of_bounds+0x33d/0x3b0 lib/ubsan.c:322 nilfs_sb2_bad_offset fs/nilfs2/the_nilfs.c:449 [inline] nilfs_load_super_block+0xdf5/0xe00 fs/nilfs2/the_nilfs.c:523 init_nilfs+0xb7/0x7d0 fs/nilfs2/the_nilfs.c:577 nilfs_fill_super+0xb1/0x5d0 fs/nilfs2/super.c:1047 nilfs_mount+0x613/0x9b0 fs/nilfs2/super.c:1317 ... In addition, since nilfs_sb2_bad_offset() performs multiplication without considering the upper bound, the computation may overflow if the disk layout parameters are not normal. This fixes these issues by inserting preliminary sanity checks for those parameters and by converting the comparison from one involving multiplication and left bit-shifting to one using division and right bit-shifting.
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Meta Information
Published
2025-10-04
Last Modified
2025-10-06
Generated
2026-05-07
AI Q&A
2025-10-04
EPSS Evaluated
2026-05-05
NVD
CVE-2022-50478
Affected Vendors & Products
Showing 1 associated CPE
Vendor Product Version / Range
linux linux_kernel From 5.15.160 (inc) to 5.16 (inc)
Helpful Resources
Exploitability
CWE
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KEV
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CWE ID Description
CWE-UNKNOWN
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AI Powered Q&A
Can you explain this vulnerability to me?

This vulnerability exists in the Linux kernel's nilfs2 filesystem code, specifically in the nilfs_sb2_bad_offset() function. If the block size exponent information in the on-disk superblock is corrupted, it can cause a shift-out-of-bounds operation leading to a kernel panic when mounting the filesystem. The issue arises because the function performs bit-shifting and multiplication without proper bounds checking, which can cause overflow or invalid operations. The patch fixes this by adding sanity checks and changing the calculations to prevent these out-of-bounds shifts and overflows.


How can this vulnerability impact me? :

This vulnerability can cause a kernel panic during the mounting of a nilfs2 filesystem if the superblock data is corrupted. This can lead to system instability or denial of service, as the kernel may crash or halt unexpectedly when accessing the affected filesystem.


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