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.
Product status
1da177e4c3f41524e886b7f1b8a0c1fc7321cac2 (git) before 95ae5ee6069d9a5945772625f289422ef659221a
1da177e4c3f41524e886b7f1b8a0c1fc7321cac2 (git) before a4259e72363e1ea204a97292001a9fc36c7e52fd
1da177e4c3f41524e886b7f1b8a0c1fc7321cac2 (git) before c3705c82b7406a15ef38a610d03bf6baa43d6e0c
1da177e4c3f41524e886b7f1b8a0c1fc7321cac2 (git) before 9242ff6245527a3ebb693ddd175493b38ddca72f
1da177e4c3f41524e886b7f1b8a0c1fc7321cac2 (git) before 0c40fa81f850556e9aa0185fede9ef1112db7b39
1da177e4c3f41524e886b7f1b8a0c1fc7321cac2 (git) before 8b69608c6b6779a7ab07ce4467a56df90152cfb9
1da177e4c3f41524e886b7f1b8a0c1fc7321cac2 (git) before b62a1e59d8716bbd2e73660743fe06acc97ed7d1
1da177e4c3f41524e886b7f1b8a0c1fc7321cac2 (git) before 37bfb464ddca87f203071b5bd562cd91ddc0b40a
2.6.12
Any version before 2.6.12
5.4.296 (semver)
5.10.240 (semver)
5.15.187 (semver)
6.1.143 (semver)
6.6.96 (semver)
6.12.36 (semver)
6.15.4 (semver)
6.16 (original_commit_for_fix)
References
lists.debian.org/debian-lts-announce/2025/10/msg00008.html
lists.debian.org/debian-lts-announce/2025/10/msg00007.html
git.kernel.org/...c/95ae5ee6069d9a5945772625f289422ef659221a
git.kernel.org/...c/a4259e72363e1ea204a97292001a9fc36c7e52fd
git.kernel.org/...c/c3705c82b7406a15ef38a610d03bf6baa43d6e0c
git.kernel.org/...c/9242ff6245527a3ebb693ddd175493b38ddca72f
git.kernel.org/...c/0c40fa81f850556e9aa0185fede9ef1112db7b39
git.kernel.org/...c/8b69608c6b6779a7ab07ce4467a56df90152cfb9
git.kernel.org/...c/b62a1e59d8716bbd2e73660743fe06acc97ed7d1
git.kernel.org/...c/37bfb464ddca87f203071b5bd562cd91ddc0b40a