CVE-2022-50478

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.

PUBLISHED Reserved 2025-10-04 | Published 2025-10-04 | Updated 2025-10-04 | Assigner Linux

Product status

References

git.kernel.org/...c/6b0ea3df56cccd53398d0289f399f19d43136b2e

git.kernel.org/...c/a6f89b10042baca218c8598d6db5a44c7e32625f

git.kernel.org/...c/9b3ba54025357440d6c4414c670984f628c6f6bf

git.kernel.org/...c/d706485dffbbbf848e681edda29c7a46ac55698c

git.kernel.org/...c/d464b035c0613856d012cf1704879d3ff3f057fb

git.kernel.org/...c/b47f5c579c8186f7f5ab5e4254e0734ea5b7bf7a

git.kernel.org/...c/1012ff77284e3bec0ec0a35a820b03ec43dec2cc

git.kernel.org/...c/62d11ec205ef14d8acf172cfc9904fdbf200025a

git.kernel.org/...c/610a2a3d7d8be3537458a378ec69396a76c385b6

cve.org (CVE-2022-50478)

nvd.nist.gov (CVE-2022-50478)

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