CVE-2025-38230

jfs: validate AG parameters in dbMount() to prevent crashes

State: Published
Severity: 7.8 High
Published: Jul 4, 2025
Updated: Aug 5, 2026
Reserved: Apr 16, 2025

Description

In the Linux kernel, the following vulnerability has been resolved:

jfs: validate AG parameters in dbMount() to prevent crashes

Validate db_agheight, db_agwidth, and db_agstart in dbMount to catch corrupted metadata early and avoid undefined behavior in dbAllocAG. Limits are derived from L2LPERCTL, LPERCTL/MAXAG, and CTLTREESIZE:

- agheight: 0 to L2LPERCTL/2 (0 to 5) ensures shift (L2LPERCTL - 2*agheight) >= 0. - agwidth: 1 to min(LPERCTL/MAXAG, 2^(L2LPERCTL - 2*agheight)) ensures agperlev >= 1. - Ranges: 1-8 (agheight 0-3), 1-4 (agheight 4), 1 (agheight 5). - LPERCTL/MAXAG = 1024/128 = 8 limits leaves per AG; 2^(10 - 2*agheight) prevents division to 0. - agstart: 0 to CTLTREESIZE-1 - agwidth*(MAXAG-1) keeps ti within stree (size 1365). - Ranges: 0-1237 (agwidth 1), 0-348 (agwidth 8).

UBSAN: shift-out-of-bounds in fs/jfs/jfs_dmap.c:1400:9 shift exponent -335544310 is negative CPU: 0 UID: 0 PID: 5822 Comm: syz-executor130 Not tainted 6.14.0-rc5-syzkaller #0 Hardware name: Google Compute Engine/Google Compute Engine, BIOS Google 02/12/2025 Call Trace: <TASK> __dump_stack lib/dump_stack.c:94 [inline] dump_stack_lvl+0x241/0x360 lib/dump_stack.c:120 ubsan_epilogue lib/ubsan.c:231 [inline] __ubsan_handle_shift_out_of_bounds+0x3c8/0x420 lib/ubsan.c:468 dbAllocAG+0x1087/0x10b0 fs/jfs/jfs_dmap.c:1400 dbDiscardAG+0x352/0xa20 fs/jfs/jfs_dmap.c:1613 jfs_ioc_trim+0x45a/0x6b0 fs/jfs/jfs_discard.c:105 jfs_ioctl+0x2cd/0x3e0 fs/jfs/ioctl.c:131 vfs_ioctl fs/ioctl.c:51 [inline] __do_sys_ioctl fs/ioctl.c:906 [inline] __se_sys_ioctl+0xf5/0x170 fs/ioctl.c:892 do_syscall_x64 arch/x86/entry/common.c:52 [inline] do_syscall_64+0xf3/0x230 arch/x86/entry/common.c:83 entry_SYSCALL_64_after_hwframe+0x77/0x7f

Found by Linux Verification Center (linuxtesting.org) with Syzkaller.

Scores

CVSS	Score	Vector	Source
3.1	7.8 High	CVSS:3.1/AV:L/AC:L/PR:N/UI:R/S:U/C:H/I:H/A:H	Linux

Weaknesses

The record names no weakness.

Affected Products

Product	Versions
LinuxLinux	1da177e4c3f41524e886b7f1b8a0c1fc7321cac2 to before 95ae5ee6069d9a5945772625f289422ef659221aAffected 1da177e4c3f41524e886b7f1b8a0c1fc7321cac2 to before a4259e72363e1ea204a97292001a9fc36c7e52fdAffected 1da177e4c3f41524e886b7f1b8a0c1fc7321cac2 to before c3705c82b7406a15ef38a610d03bf6baa43d6e0cAffected 1da177e4c3f41524e886b7f1b8a0c1fc7321cac2 to before 9242ff6245527a3ebb693ddd175493b38ddca72fAffected 1da177e4c3f41524e886b7f1b8a0c1fc7321cac2 to before 0c40fa81f850556e9aa0185fede9ef1112db7b39Affected 1da177e4c3f41524e886b7f1b8a0c1fc7321cac2 to before 8b69608c6b6779a7ab07ce4467a56df90152cfb9Affected 1da177e4c3f41524e886b7f1b8a0c1fc7321cac2 to before b62a1e59d8716bbd2e73660743fe06acc97ed7d1Affected 1da177e4c3f41524e886b7f1b8a0c1fc7321cac2 to before 37bfb464ddca87f203071b5bd562cd91ddc0b40aAffected
LinuxLinux	2.6.12Affected before 2.6.12Not affected 5.4.296 through 5.4.Not affected 5.10.240 through 5.10.Not affected 5.15.187 through 5.15.Not affected 6.1.143 through 6.1.Not affected 6.6.96 through 6.6.Not affected 6.12.36 through 6.12.Not affected 6.15.4 through 6.15.*Not affected 6.16 and laterNot affected

Product

Versions

LinuxLinux

1da177e4c3f41524e886b7f1b8a0c1fc7321cac2 to before 95ae5ee6069d9a5945772625f289422ef659221aAffected
1da177e4c3f41524e886b7f1b8a0c1fc7321cac2 to before a4259e72363e1ea204a97292001a9fc36c7e52fdAffected
1da177e4c3f41524e886b7f1b8a0c1fc7321cac2 to before c3705c82b7406a15ef38a610d03bf6baa43d6e0cAffected
1da177e4c3f41524e886b7f1b8a0c1fc7321cac2 to before 9242ff6245527a3ebb693ddd175493b38ddca72fAffected
1da177e4c3f41524e886b7f1b8a0c1fc7321cac2 to before 0c40fa81f850556e9aa0185fede9ef1112db7b39Affected
1da177e4c3f41524e886b7f1b8a0c1fc7321cac2 to before 8b69608c6b6779a7ab07ce4467a56df90152cfb9Affected
1da177e4c3f41524e886b7f1b8a0c1fc7321cac2 to before b62a1e59d8716bbd2e73660743fe06acc97ed7d1Affected
1da177e4c3f41524e886b7f1b8a0c1fc7321cac2 to before 37bfb464ddca87f203071b5bd562cd91ddc0b40aAffected

LinuxLinux

2.6.12Affected
before 2.6.12Not affected
5.4.296 through 5.4.*Not affected
5.10.240 through 5.10.*Not affected
5.15.187 through 5.15.*Not affected
6.1.143 through 6.1.*Not affected
6.6.96 through 6.6.*Not affected
6.12.36 through 6.12.*Not affected
6.15.4 through 6.15.*Not affected
6.16 and laterNot affected

References

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