CVE-2026-98259 in Linux
Tóm tắt
Bởi VulDB • 07/10/2026
Trong kernel Linux, lỗ hổng sau đây đã được khắc phục:
fs/dax: kiểm tra entry bằng không hoặc rỗng trước khi chuyển đổi xarray entry
Việc gọi dax_to_folio() với một entry rỗng gây ra lỗi kernel panic như bên dưới khi khởi động VM có lưu trữ DAX (Direct Access) được bật.
Patch này kiểm tra entry rỗng trước khi gọi dax_to_folio() trên các hàm dax_associate_entry(), dax_disassociate_entry(), và dax_busy_page().
Commit 98c183a4fccf ("fs/dax: don't disassociate zero page entries") đã thêm các guard trong đường dẫn associate và disassociate, nhưng các guard này vẫn nằm sau khi gọi dax_to_folio(), và hàm dax_busy_page() vẫn gặp phải cùng vấn đề.
[ 0.737679] EXT4-fs (pmem0p1): mounted filesystem 79676804-7c8b-491a-b2a6-9bae3c72af70 ro with ordered data mode. Quota mode: disabled.
[ 0.737891] VFS: Mounted root (ext4 filesystem) readonly on device 259:1.
[ 0.739119] devtmpfs: mounted
[ 0.739476] Freeing unused kernel memory: 1920K
[ 0.740156] Run /sbin/init as init process
[ 0.740229] with arguments:
[ 0.740286] /sbin/init
[ 0.740321] with environment:
[ 0.740369] HOME=/
[ 0.740400] TERM=linux
[ 0.743162] Unable to handle kernel paging request at virtual address fffffdffbf000008
[ 0.743285] Mem abort info:
[ 0.743316] ESR = 0x0000000096000006
[ 0.743371] EC = 0x25: DABT (current EL), IL = 32 bits
[ 0.743444] SET = 0, FnV = 0
[ 0.743489] EA = 0, S1PTW = 0
[ 0.743545] FSC = 0x06: level 2 translation fault
[ 0.743610] Data abort info:
[ 0.743656] ISV = 0, ISS = 0x00000006, ISS2 = 0x00000000
[ 0.743720] CM = 0, WnR = 0, TnD = 0, TagAccess = 0
[ 0.743785] GCS = 0, Overlay = 0, DirtyBit = 0, Xs = 0
[ 0.743848] swapper pgtable: 4k pages, 48-bit VAs, pgdp=00000000b9d17000
[ 0.743931] [fffffdffbf000008] pgd=10000000bfa3d403, p4d=10000000bfa3d403, pud=1000000040bfe403, pmd=0000000000000000
[ 0.744070] Internal error: Oops: 0000000096000006 [#1] SMP
[ 0.748888] CPU: 0 UID: 0 PID: 1 Comm: init Not tainted 6.18.4 #1 NONE
[ 0.749421] pstate: 004000c5 (nzcv daIF +PAN -UAO -TCO -DIT -SSBS BTYPE=--)
[ 0.749969] pc : dax_disassociate_entry.constprop.0+0x20/0x50
[ 0.750444] lr : dax_insert_entry+0xcc/0x408
[ 0.750802] sp : ffff80008000b9e0
[ 0.751083] x29: ffff80008000b9e0 x28: 0000000000000000 x27: 0000000000000000
[ 0.751682] x26: 0000000001963d01 x25: ffff0000004f7d90 x24: 0000000000000000
[ 0.752264] x23: 0000000000000000 x22: ffff80008000bcc8 x21: 0000000000000011
[ 0.752836] x20: ffff80008000ba90 x19: 0000000001963d01 x18: 0000000000000000
[ 0.753407] x17: 0000000000000000 x16: 0000000000000000 x15: 0000000000000000
[ 0.753970] x14: ffffbf3154b9ae70 x13: 0000000000000000 x12: ffffbf3154b9ae70
[ 0.754548] x11: ffffffffffffffff x10: 0000000000000000 x9 : 0000000000000000
[ 0.755122] x8 : 000000000000000d x7 : 000000000000001f x6 : 0000000000000000
[ 0.755707] x5 : 0000000000000000 x4 : 0000000000000000 x3 : fffffdffc0000000
[ 0.756287] x2 : 0000000000000008 x1 : 0000000040000000 x0 : fffffdffbf000000
[ 0.756871] Call trace:
[ 0.757107] dax_disassociate_entry.constprop.0+0x20/0x50 (P)
[ 0.757592] dax_iomap_pte_fault+0x4fc/0x808
[ 0.757951] dax_iomap_fault+0x28/0x30
[ 0.758258] ext4_dax_huge_fault+0x80/0x2dc
[ 0.758594] ext4_dax_fault+0x10/0x3c
[ 0.758892] __do_fault+0x38/0x12c
[ 0.759175] __handle_mm_fault+0x530/0xcf0
[ 0.759518] handle_mm_fault+0xe4/0x230
[ 0.759833] do_page_fault+0x17c/0x4dc
[ 0.760144] do_translation_fault+0x30/0x38
[ 0.760483] do_mem_abort+0x40/0x8c
[ 0.760771] el0_ia+0x4c/0x170
[ 0.761032] el0t_64_sync_handler+0xd8/0xdc
[ 0.761371] el0t_64_sync+0x168/0x16c
[ 0.761677] Code: f9453021 f2dfbfe3 cb813080 8b001860 (f9400401)
[ 0.762168] ---[ end trace 0000000000000000 ]---
[ 0.762550] note: init[1] exited with irqs disabled
[ 0.762631] Kernel panic - not syncing: Attempted to kill init! exitcode=0x0000000b
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