CVE-2025-38230 Information

Jul 05, 2025 cve

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 - 2agheight) >= 0.
  • agwidth: 1 to min(LPERCTL/MAXAG 2^(L2LPERCTL - 2agheight)) 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 - 2agheight) 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: __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.

Reference

https://git.kernel.org/stable/c/37bfb464ddca87f203071b5bd562cd91ddc0b40a https://git.kernel.org/stable/c/b62a1e59d8716bbd2e73660743fe06acc97ed7d1

CNNVD-202507-490 (Published: 2025-07-04)

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