CVE-2026-98259 in Linux
Resumen
por VulDB • 2026-10-06
En el kernel de Linux, se ha resuelto la siguiente vulnerabilidad:
fs/dax: comprobar si hay una entrada nula o vacía antes de convertir la entrada xarray
Llamar a dax_to_folio() con una entrada vacía provoca un kernel panic (pánico del núcleo) al arrancar una máquina virtual (VM) con almacenamiento DAX habilitado.
Este parche comprueba si la entrada está vacía antes de llamar a dax_to_folio() en dax_associate_entry(), dax_disassociate_entry() y dax_busy_page().
El commit 98c183a4fccf ("fs/dax: no desasociar entradas de página cero") añadió protecciones (guards) en las rutas de asociación y desasociación, pero dichas protecciones aún se encuentran después de dax_to_folio(), y dax_busy_page() sigue teniendo el mismo problema.
[ 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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